BMW G20 and G21 3 Series engines: every engine, fitment and price

The seventh-generation 3 Series has been built since 2018 as the G20 saloon and G21 Touring. Engines include the B48 and B58 petrols and the B47 and B57 diesels, plus plug-in hybrid variants.

Used G20 engines usually come from accident-damaged cars. This guide explains which engine each model uses and what to check before buying.

In total, 10 model and engine combinations are listed for the BMW G20 and G21 3 Series in our data, using 4 engine families: B47, B38, B48 and B46 and B58. Production covered 2018–. We currently hold 182 engines that suit these cars.

Every BMW G20 and G21 3 Series engine at a glance

BMW G20 and G21 3 Series: petrol engines

B38 in the BMW G20 and G21 3 Series

G20 318i: B38B15, 1.5 L, 136 hp and 220 Nm (2014–2026). See every B38B15 in stock.

BMW launched the B38 in 2014 as part of its modular B-series.

On the B38, our workshop watches for coolant leaks, ignition coils and engine mounts. Front-drive (B38A) and rear-drive (B38B) versions are not interchangeable without changes.

Read our full B38 guide

B48 and B46 in the BMW G20 and G21 3 Series

G20 330i: B48B20, 2.0 L, 258 hp and 400 Nm (2014–2026). See every B48B20 in stock.

For the G20 330i, BMW fitted the B48B20TU — 2.0 L, turbocharged, 258 hp. See every B48B20TU in stock.

The G20 330i uses the B48B20B, a 2.0 L inline-4 rated at 258 hp and 400 Nm, built 2019–2026. See every B48B20B in stock.

BMW launched the B48 as the four-cylinder member of the B-series with a 500 cc-per-cylinder layout, twin-scroll turbo and integrated exhaust manifold.

On the B48 and B46, our workshop watches for coolant leaks, oil filter housing gasket and pcv and valve cover. Check front-drive (B48A) or rear-drive (B48B) before ordering.

Read our full B48 and B46 guide

We have 94 B48 and B46 engines that suit the BMW G20 and G21 3 Series, from 1.385,00 €.

B58 in the BMW G20 and G21 3 Series

G20 M340i: B58B30, 3.0 L, 340 hp and 500 Nm (2015–2026). See every B58B30 in stock.

For the G20 M340i, BMW fitted the B58B30TU — 3.0 L, turbocharged, 374 hp. See every B58B30TU in stock.

The G20 M340i uses the B58B30M1, a 3.0 L inline-6 rated at 374 hp and 500 Nm, built 2019–2026. See every B58B30M1 in stock.

BMW launched the B58 in 2015 with a closed-deck block, twin-scroll turbo and integrated manifold.

On the B58, our workshop watches for coolant leaks, oil filter housing and pcv valve. Check the version (B58B30M0, M1 or TU) before ordering.

Read our full B58 guide

We have 50 B58 engines that suit the BMW G20 and G21 3 Series, from 2.767,00 €.

BMW G20 and G21 3 Series: diesel engines

B47 in the BMW G20 and G21 3 Series

The G20 318d uses the B47D20A, a 2.0 L inline-4 rated at 150 hp and 320 Nm, built 2014–2020. See every B47D20A in stock.

G20 320d: B47D20, 2.0 L, 190 hp and 400 Nm (2014–2026). See every B47D20 in stock.

G20 320d: B47D20B, 2.0 L, 190 hp and 400 Nm (2014–2026). See every B47D20B in stock.

BMW launched the B47 in 2014 to replace the N47.

On the B47, our workshop watches for egr cooler, diesel particulate filter and injectors. Check front-drive (B47C) or rear-drive (B47D) before ordering.

Read our full B47 guide

We have 8 B47 engines that suit the BMW G20 and G21 3 Series, from 887,00 €.

Will it fit? BMW G20 and G21 3 Series engine questions

Will the B47D20A fit my BMW G20 318d?

Yes, the BMW G20 318d left the factory with the B47D20A, so a B47D20A from another car is the direct replacement. The seventh 3 Series was built 2018–, and the B47D20A was produced 2014–2020, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 318d?

We have 3 B47D20A engines from G20 donor cars, priced from 1.441,00 € to 4.623,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Will the B38B15 fit my BMW G20 318i?

The B38B15 is the original engine for the BMW G20 318i, which makes it the straightforward choice. The seventh 3 Series was built 2018–, and the B38B15 was produced 2014–2026, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 318i?

We do not have a B38B15 on the shelf for the G20 318i at the moment. Units arrive regularly; send us your VIN and we will tell you when the next one is ready and what it will cost, including delivery.

Will the B47D20B fit my BMW G20 320d?

For the BMW G20 320d, the B47D20B is the factory engine and the one to order. The seventh 3 Series was built 2018–, and the B47D20B was produced 2014–2026, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 320d?

We have 5 B47D20B engines from G20 donor cars, priced from 887,00 € to 4.242,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Will the B58B30 fit my BMW G20 M340i?

The B58B30 is the original engine for the BMW G20 M340i, which makes it the straightforward choice. The seventh 3 Series was built 2018–, and the B58B30 was produced 2015–2026, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 M340i?

We have 49 B58B30 engines from G20 donor cars, priced from 2.767,00 € to 8.132,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Will the B48B20TU fit my BMW G20 330i?

Yes, the BMW G20 330i left the factory with the B48B20TU, so a B48B20TU from another car is the direct replacement. The seventh 3 Series was built 2018–, and the B48B20TU was produced 2018–2026, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 330i?

We have 1 B48B20TU engine from G20 donor cars, priced from 4.795,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Will the B58B30TU fit my BMW G20 M340i?

The B58B30TU is the original engine for the BMW G20 M340i, which makes it the straightforward choice. The seventh 3 Series was built 2018–, and the B58B30TU was produced 2018–2026, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 M340i?

We have 1 B58B30TU engine from G20 donor cars, priced from 8.132,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Will the B48B20B fit my BMW G20 330i?

For the BMW G20 330i, the B48B20B is the factory engine and the one to order. The seventh 3 Series was built 2018–, and the B48B20B was produced 2019–2026, so check that your car's build date falls inside that window. Confirm the drive type (rear-drive or xDrive), the gearbox (manual or automatic) and the emissions standard, because these can change the sump, the flywheel and the software. Send us the VIN and we check all of it for you.

How much is a replacement engine for a BMW G20 330i?

We have 3 B48B20B engines from G20 donor cars, priced from 1.551,00 € to 2.276,00 €. Delivery to your door is included, and the engine carries a 12-month warranty when fitted by a qualified workshop. Add fitting labour and the parts you replace at the same time — seals, cooling parts and mounts — to estimate the total.

Engine swap questions for the BMW G20 and G21 3 Series

Owners often ask whether a more powerful engine from another BMW G20 and G21 3 Series model can be fitted. These answers show what each upgrade involves.

Can I fit the B48B20B from the G20 330i into a G20 318d?

It is a full conversion: the B48B20B runs on petrol and the B47D20A on diesel, so the fuel system, wiring, ECU, instrument coding and usually the gearbox change too. The gain is 108 hp and 80 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Can I fit the B58B30M1 from the G20 M340i into a G20 318d?

It is a full conversion: the B58B30M1 runs on petrol and the B47D20A on diesel, so the fuel system, wiring, ECU, instrument coding and usually the gearbox change too. The gain is 224 hp and 180 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Can I fit the B47D20B from the G20 320d into a G20 318i?

It is a full conversion: the B47D20B runs on diesel and the B38B15 on petrol, so the fuel system, wiring, ECU, instrument coding and usually the gearbox change too. The gain is 54 hp and 180 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Can I fit the B47D20A from the G20 318d into a G20 318i?

It is a full conversion: the B47D20A runs on diesel and the B38B15 on petrol, so the fuel system, wiring, ECU, instrument coding and usually the gearbox change too. The gain is 14 hp and 100 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Can I fit the B48B20B from the G20 330i into a G20 320d?

It is a full conversion: the B48B20B runs on petrol and the B47D20B on diesel, so the fuel system, wiring, ECU, instrument coding and usually the gearbox change too. The gain is 68 hp and 0 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Can I fit the B58B30M1 from the G20 M340i into a G20 320d?

It is a full conversion: the B58B30M1 runs on petrol and the B47D20B on diesel, so the fuel system, wiring, ECU, instrument coding and usually the gearbox change too. The gain is 184 hp and 100 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Can I fit the B58B30M1 from the G20 M340i into a G20 330i?

It is a conversion rather than a replacement. The B58B30M1 is an inline-6 and the B48B20B an inline-4, so mounts, sump, cooling, exhaust, wiring and ECU all change. The gain is 116 hp and 100 Nm. In Germany and most of Europe a swap must be inspected and registered; check with your testing station first.

Fitment and swap notes for the BMW G20 and G21 3 Series

• The M340i uses the B58; the M340d uses the B57 with mild-hybrid assistance.
• Mild-hybrid diesels from 2020 use a 48-volt starter-generator; check compatibility.
• Engine software must be coded to the car by a BMW dealer or specialist.

Engines from the same family usually share mounts and gearbox bolt patterns, but wiring, ECU, sump and cooling differ between versions. Moving to a different family is a conversion, not a replacement.

B47: Remaps add around 30 hp.

B38: Remaps add modest gains.

B48 and B46: Remaps add 40 to 60 hp easily.

B58: Remaps add 80 to 100 hp; it is the base for many swaps.

Known problems by engine in the BMW G20 and G21 3 Series

B47

• EGR cooler. Check the recall status for the donor car.
• Diesel particulate filter. Read the soot load.
• Injectors. Read injector correction values.

B38

• Coolant leaks. Check for coolant loss.
• Ignition coils. Read misfire counters.
• Engine mounts. Check mounts in the car.
• Carbon build-up. Borescope inspection.

B48 and B46

• Coolant leaks. Check for coolant loss.
• Oil filter housing gasket. Check the filter housing.
• PCV and valve cover. Look for oil on the head.
• Water pump. Check for coolant trails.

B58

• Coolant leaks. Check for coolant loss.
• Oil filter housing. Check below the housing.
• PCV valve. Look for oil in the intake.

How to identify the right engine for your BMW G20 and G21 3 Series

Start with the VIN. The last seven characters identify your car in BMW's systems, and from them we can confirm the engine code, the production date, the gearbox and whether the car has xDrive. That is the only reliable way to order.

Next, check the stamp on the block. On most BMW four- and six-cylinder engines it sits on the left side of the block below the intake; on V engines it is usually at the back near the gearbox. The stamp shows the engine code and serial number.

Finally, compare the ancillaries. Two engines with the same code can carry different turbos, injectors, manifolds or sensors depending on the model and market. Our listings show what is fitted to each unit.

BMW G20 and G21 3 Series engine prices

We currently hold 182 BMW G20 and G21 3 Series engine engines. The cheapest is 830,00 €, the most expensive 8.132,00 €, and half of them cost less than 3.678,00 €.

Prices depend on the exact version, the donor's mileage, how complete the engine is and the demand for that code. Higher-output versions, low mileage and dressed engines with turbo, injectors and ancillaries cost more; long blocks and higher mileage cost less.

BMW G20 and G21 3 Series engine prices by model year

Engines from 2015–2019 have a median of 3.641,00 €, while units from 2025–2029 sit at 5.761,00 €. Newer engines usually cost more because they come from younger donor cars with lower mileage and later updates.

BMW G20 and G21 3 Series engine prices by mileage

Mileage matters less than history on a well-maintained BMW engine, but it is a useful guide. A low-mileage unit from a younger car gives you more life for a modest premium.

BMW G20 and G21 3 Series engines in stock now

Here is a selection of BMW G20 and G21 3 Series engine engines currently on our shelves, photographed in the yard. Click any of them for the full photographs, mileage and specification.

BMW G20 M340i B58B30M1 Engine 2021, 194,400 km5.444,00 €BMW G20 330i B48B20 Engine 2024, 61,400 km3.466,00 €BMW G20 330i B48B20 Engine 2015, 19,200 km3.931,00 €BMW G20 330i B48B20 Engine 2024, 97,700 km2.771,00 €BMW G20 M340i B58B30M1 Engine 2020, 164,300 km7.368,00 €BMW G20 M340i B58B30M1 Engine 2023, 108,100 km7.144,00 €BMW G20 330i B48B20 Engine 2016, 113,900 km3.191,00 €BMW G20 330i B48B20 Engine 2024, 78,300 km3.055,00 €BMW G20 M340i B58B30M1 Engine 2021, 103,500 km6.295,00 €BMW G20 330i B48B20 Engine 2017, 162,200 km3.018,00 €BMW G20 330i B48B20 Engine 2021, 151,600 km3.624,00 €BMW G20 330i B48B20 Engine 2019, 48,300 km3.020,00 €

BMW G20 M340i B58B30M1 Engine 2021, 194,400 km — 5.444,00 €, reduced from 6.550,00 €. It comes from a 2021 donor car with 194,400 km, and 23 units are available. We can confirm fitment against your VIN the same day.

BMW G20 330i B48B20 Engine 2024, 61,400 km — 3.466,00 €, reduced from 4.350,00 €. It comes from a 2024 donor car with 61,400 km, and 28 units are available. We can confirm fitment against your VIN the same day.

BMW G20 330i B48B20 Engine 2015, 19,200 km — 3.931,00 €, reduced from 4.700,00 €. It comes from a 2015 donor car with 19,200 km, and 18 units are available. We can confirm fitment against your VIN the same day.

BMW G20 330i B48B20 Engine 2024, 97,700 km — 2.771,00 €, reduced from 3.950,00 €. It comes from a 2024 donor car with 97,700 km, and 7 units are available. The listing shows every side of the engine and the fitted parts.

BMW G20 M340i B58B30M1 Engine 2020, 164,300 km — 7.368,00 €, reduced from 8.350,00 €. It comes from a 2020 donor car with 164,300 km, and 25 units are available. The listing shows every side of the engine and the fitted parts.

BMW G20 M340i B58B30M1 Engine 2023, 108,100 km — 7.144,00 €, reduced from 7.750,00 €. It comes from a 2023 donor car with 108,100 km, and 28 units are available. We can confirm fitment against your VIN the same day.

BMW G20 330i B48B20 Engine 2016, 113,900 km — 3.191,00 €, reduced from 4.050,00 €. It comes from a 2016 donor car with 113,900 km, and 11 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW G20 330i B48B20 Engine 2024, 78,300 km — 3.055,00 €, reduced from 3.800,00 €. It comes from a 2024 donor car with 78,300 km, and 25 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW G20 M340i B58B30M1 Engine 2021, 103,500 km — 6.295,00 €, reduced from 7.150,00 €. It comes from a 2021 donor car with 103,500 km, and 26 units are available. We can confirm fitment against your VIN the same day.

BMW G20 330i B48B20 Engine 2017, 162,200 km — 3.018,00 €, reduced from 3.850,00 €. It comes from a 2017 donor car with 162,200 km, and 7 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW G20 330i B48B20 Engine 2021, 151,600 km — 3.624,00 €, reduced from 4.400,00 €. It comes from a 2021 donor car with 151,600 km, and 14 units are available. The listing shows every side of the engine and the fitted parts.

BMW G20 330i B48B20 Engine 2019, 48,300 km — 3.020,00 €, reduced from 3.900,00 €. It comes from a 2019 donor car with 48,300 km, and 23 units are available. We can confirm fitment against your VIN the same day.

Buying checklist for a BMW G20 and G21 3 Series engine

1. Confirm the exact engine code. Read the code stamped on the block and compare it with the code for your car. Send us the last seven characters of the VIN and we confirm the match before anything is paid.
2. Ask how the donor car was damaged. Most good used engines come from cars with body damage. A front-end impact can crack sensors, the timing cover or the sump; a rear or side impact usually leaves the engine untouched. The yard records the damage on each unit.
3. Compression or leak-down figures. Even compression across all cylinders tells you more than mileage. Ask for the figures, not just a pass or fail, and compare the highest and lowest readings: a spread above 10 to 15 percent deserves a question.
4. Look at the oil and coolant. Clean oil without metal particles and coolant without oil are good signs. Milky oil, oily coolant or a burnt smell mean the engine needs further checks before it is fitted.
5. Photographs from every side. Good suppliers photograph the actual engine you will receive. Look for the block stamp, the sump, the timing cover and any broken brackets or connectors in the pictures.
6. List of what is fitted. Engines are sold with different ancillaries: some have the turbo, injectors, manifolds, alternator and starter, others are long blocks. Agree the list in writing so you know which parts must come from your old engine.
7. Sump, oil pickup and drive variants. Rear-drive, xDrive and front-drive cars can use different sumps, oil pickups and engine mounts even with the same engine code. Check that the sump matches your subframe and front axle.
8. Gearbox and flywheel match. Manual and automatic engines differ at the flywheel or flexplate, and sometimes at the crankshaft spigot. Make sure the engine you buy matches your gearbox or that you transfer the right parts.
9. Warranty terms in writing. Read what the warranty covers, how long it runs and what fitting conditions apply. Most warranties require a qualified workshop, new fluids and filters, and replacement of the cooling parts that caused the original failure.
10. Why your old engine failed. Before fitting a replacement, find out why the original failed. An overheating radiator, a blocked intercooler or a failed turbo can destroy a second engine if they are not fixed.
11. Turbocharger shaft play and oil. Rotate the compressor wheel by hand. A small amount of side play is normal; in-and-out play or wheel contact with the housing is not. Oil pooled in the intake or intercooler pipes points to worn seals.
12. Injector correction values. On a diesel that can be run before removal, the injector correction values show whether one injector is delivering more or less fuel than the others. Large deviations mean an injector is on its way out.
13. Particulate filter and EGR history. Short-trip diesels clog their DPF and EGR systems. The engine may be fine, but ask whether the donor car had DPF warnings, and plan to clean or check your own filter before fitting.
14. Timing chain noise. Listen for a rattle at the front of the engine for the first seconds after a cold start. On an engine that cannot be run, look at the chain guides through the oil filler or with the valve cover off.
15. Gearbox-end timing chain. On this engine the timing chain sits at the gearbox end, so replacing it normally means removing the engine. If the chain has not been replaced, the time to do it is before the engine goes into your car.
16. VANOS operation. Rough idle, a rattle from the front of the head and a loss of torque at low revs point to VANOS seals or solenoids. These are serviceable parts and are easier to renew with the engine out.
17. Double VANOS units and solenoids. Ask for the adaptation values or fault history if the engine was running. Solenoids are inexpensive and are often replaced as a matter of course on a used engine.
18. Valvetronic motor and eccentric shaft sensor. The Valvetronic motor and its sensor cause limp-mode faults when they fail. Inspect the connector and the seal around the motor for oil.
19. Injectors and high-pressure fuel pump. Direct-injection engines rely on high-pressure pumps and precise injectors. Ask whether the injectors are original or updated and whether there were fuel pressure faults.

Fitting an engine to your BMW G20 and G21 3 Series

1. Compare the engines side by side. Put the replacement next to the old engine and compare sensors, brackets, connectors, the sump, the starter and the flywheel or flexplate. Note anything that must be transferred.
2. Transfer the parts that differ. Move the parts that are specific to your car, such as the engine harness on some models, the sump on xDrive cars or the air conditioning compressor bracket. Use new seals and gaskets for everything you move.
3. Replace the rear main seal and drive parts. With the engine out, the rear crankshaft seal is easy to reach. Fit a new one, inspect the flywheel and clutch on manual cars or the converter seal on automatics.
4. Renew the cooling system. Most engine failures start with cooling. Fit a new water pump, thermostat and hoses, check the radiator and fan, and use the correct coolant.
5. Fit new engine mounts. Old mounts transfer vibration and can let the engine move enough to damage hoses. They are cheap and easy to replace with the engine out.
6. Inspect or replace the timing chain parts. Look at the guides and tensioner. On high-mileage engines, replacing them now costs far less than doing it later.
7. Replace the rear timing chain if in doubt. On engines with the chain at the gearbox end, chain work needs the engine out. If the history is unknown, replace the chain, guides and tensioner before fitting.
8. Prepare the turbo. Fit new oil feed and return seals, clean the intercooler and pipes of any oil or debris from the old engine, and prime the turbo with oil before starting.
9. Code the injectors and bleed the fuel. Enter the injector correction codes into the ECU, check the glow plugs and bleed the fuel system so the engine does not crank dry.
10. Check the particulate filter. If the old engine failed with oil or coolant entering the exhaust, the DPF may be contaminated. Check its back-pressure before relying on it.
11. Clean the intake. If the old engine failed internally, debris can be in the intake or intercooler. Clean them so nothing reaches the new engine.
12. Fill with the right oil and prime it. Fill with new oil of the correct specification and a new filter. Crank with the fuel and ignition disabled until oil pressure builds.
13. Coding and adaptations. On modern BMWs, the engine ECU must be matched to the car's immobiliser (CAS, FEM or BDC). Reset adaptations, register the battery and clear faults with diagnostic software.
14. Reset VANOS adaptations. Clear the VANOS adaptations so the ECU learns the camshaft positions of the new engine.
15. Teach the Valvetronic limit stops. Run the Valvetronic learning routine so the ECU knows the eccentric shaft limits.
16. First start and leak check. Start the engine, let it idle and watch oil pressure, temperature and fault codes. Check for leaks and bleed the cooling system.
17. First 1,000 km. Drive gently for the first few hundred kilometres, vary the engine speed and avoid full load. Change the oil and filter after about 1,000 km to remove any assembly debris.

Diagnosing engine trouble in a BMW G20 and G21 3 Series

If your current engine is showing one of these symptoms, this table helps you judge whether it can be repaired or whether a replacement engine is the better route.

Knocking from the bottom of the engine. A deep knock that rises with engine speed usually means worn rod or main bearings. Stop driving: bearing failure ends with a broken connecting rod. A used engine is normally the most economical fix once the bottom end is damaged.

Overheating or losing coolant. Coolant loss without visible leaks points to a head gasket or a cracked head; visible leaks point to the water pump, hoses, thermostat housing or expansion tank. Overheating should be fixed before it warps the head.

White smoke that smells sweet. Coolant burning in the cylinders, from a head gasket, a cracked head or, on diesels, a leaking EGR cooler. Check the coolant level and look for oil in the coolant.

Blue smoke. Oil burning in the cylinders. A puff on start-up points to valve stem seals; constant smoke under load points to piston rings or, on turbo engines, turbo seals.

Rough idle or misfire. Ignition coils, spark plugs, injectors and vacuum leaks are the usual causes. A misfire on one cylinder that moves when you swap coils is a coil; one that stays is a plug, injector or compression problem.

Loss of power. Start with the simple things: air filter, boost leaks on turbo engines, fuel pressure and fault codes. A gradual loss with poor compression on a test points to internal wear.

Rattle for a few seconds after a cold start. The classic sign of a weak timing chain tensioner or stretched chain. It must be checked quickly: a chain that jumps a tooth can bend valves.

Rattle or whine from the gearbox end. On engines with the timing chain at the rear, a rattle or whine from the back of the engine is the warning sign of chain stretch or guide wear.

Whistle, loss of boost or limp mode. A split charge pipe, a sticking wastegate or worn turbo bearings. Check the pipes first, then the turbo shaft for play.

Black smoke under acceleration. Too much fuel for the air available: boost leaks, a sticking EGR valve, a dirty air mass meter or a leaking injector.

Hard starting when cold. Glow plugs or the glow plug control unit. On older diesels, also check the injection pump and fuel lines for air leaks.

Particulate filter warning. Short trips stop the DPF from regenerating. A long motorway run often clears it; a filter that keeps blocking may be covering an injector, EGR or turbo problem.

Poor low-down torque and uneven idle. VANOS seals or solenoids. The engine may run well at high revs but feel flat and lumpy at low speed.

Limp mode with a Valvetronic fault. The Valvetronic motor, its eccentric shaft sensor or the wiring. The engine runs on a reduced throttle until it is repaired.

Long cranking before the engine starts. On direct-injection engines, a weak high-pressure fuel pump or leaking injector lets pressure drop when the engine is off.

Repair or replace the engine in your BMW G20 and G21 3 Series?

As a rule, bolt-on faults are worth repairing and internal damage is not. Seals, sensors, coils, injectors, pumps and turbos can be replaced in the car. Once the bearings, crankshaft, bores or head of an engine are damaged, a used engine is usually cheaper and quicker than a rebuild.

Timing chain work on the engine needs the engine removed. When the chain has failed and damaged valves or pistons, a replacement engine with a sound chain is often the same price as the repair.

Ask your workshop for a written diagnosis before deciding. A compression test, an oil analysis and a borescope inspection take an hour or two and remove most of the guesswork.

Delivery, warranty and payment

Every BMW G20 and G21 3 Series engine we sell is drained, sealed at each opening, strapped to a heat-treated pallet and shrink-wrapped before it leaves Hamburg. You receive photographs of the packed engine and a tracking number.

Door-to-door delivery is included to the address you give at checkout. Typical delivery takes three to five working days within Germany and neighbouring countries and five to ten working days to the rest of Europe and the UK.

Every engine carries a 12-month warranty on eligible internal failure when a qualified workshop fits it with new fluids and filters. Payment is by card, bank transfer or crypto; your invoice is emailed as soon as you order.

We deliver BMW G20 and G21 3 Series engines from Hamburg to customers across Europe and beyond. Typical door-to-door times and customs status:

Times are typical for pallet delivery after dispatch and can vary with holidays and remote addresses. Business buyers in the EU with a valid VAT number can order without German VAT.

Questions about BMW G20 and G21 3 Series engines

Will the B47D20 engine fit my BMW G20 320d?

Yes, if your BMW G20 320d was built with the B47D20. BMW used this 2.0 liter (1,995 cc) diesel engine with 140 kW (190 HP) in the G20 320d from about 2014 to 2023.

In our records the B47D20 is the engine for the G20 320d, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your G20 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B47 Engines · Search B47D20 in the shop

How much is a replacement B47D20 engine for a BMW G20 320d?

A used B47D20 for the BMW G20 320d costs from about 2.150 € to 3.450 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B47D20 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B47 Engines · Search B47D20 in the shop

Will the B47D20 engine fit my BMW G21 320d?

Yes, if your BMW G21 320d was built with the B47D20. BMW used this 2.0 liter (1,995 cc) diesel engine with 140 kW (190 HP) in the G21 320d from about 2014 to 2023.

In our records the B47D20 is the engine for the G21 320d, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your G21 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B47 Engines · Search B47D20 in the shop

How much is a replacement B47D20 engine for a BMW G21 320d?

A used B47D20 for the BMW G21 320d costs from about 2.150 € to 3.450 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B47D20 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B47 Engines · Search B47D20 in the shop

Will the B48B20 engine fit my BMW G20 330i?

Yes, if your BMW G20 330i was built with the B48B20. BMW used this 2.0 liter (1,998 cc) petrol engine with 190 kW (258 HP) in the G20 330i from about 2015 to 2025.

In our records the B48B20 is the engine for the G20 330i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your G20 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines · Search B48B20 in the shop

How much is a replacement B48B20 engine for a BMW G20 330i?

A used B48B20 for the BMW G20 330i costs from about 2.650 € to 4.200 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B48B20 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines · Search B48B20 in the shop

Will the B48B20 engine fit my BMW G21 330i?

Yes, if your BMW G21 330i was built with the B48B20. BMW used this 2.0 liter (1,998 cc) petrol engine with 190 kW (258 HP) in the G21 330i from about 2015 to 2025.

In our records the B48B20 is the engine for the G21 330i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your G21 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines · Search B48B20 in the shop

How much is a replacement B48B20 engine for a BMW G21 330i?

A used B48B20 for the BMW G21 330i costs from about 2.650 € to 4.200 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B48B20 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines · Search B48B20 in the shop

Will the B58B30M1 engine fit my BMW G20 M340i?

Yes, if your BMW G20 M340i was built with the B58B30M1. BMW used this 3.0 liter (2,998 cc) petrol engine with 275 kW (374 HP) in the G20 M340i from about 2019 to 2026.

In our records the B58B30M1 is the engine for the G20 M340i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your G20 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B58 Engines · Search B58B30M1 in the shop

How much is a replacement B58B30M1 engine for a BMW G20 M340i?

A used B58B30M1 for the BMW G20 M340i costs from about 5.200 € to 7.950 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B58B30M1 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B58 Engines · Search B58B30M1 in the shop

Questions about the engines in the BMW G20 and G21 3 Series

Will the B38A15 engine fit my BMW F45 218i?

Yes, if your BMW F45 218i was built with the B38A15. BMW used this 1.5 liter (1,499 cc) petrol engine with 100 kW (136 HP) in the F45 218i from about 2014 to 2024.

In our records the B38A15 is the engine for the F45 218i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your F45 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B38 Engines · Search B38A15 in the shop

Will the B58B30 engine fit my BMW F30 340i?

Yes, if your BMW F30 340i was built with the B58B30. BMW used this 3.0 liter (2,998 cc) petrol engine with 250 kW (340 HP) in the F30 340i from about 2015 to 2020.

In our records the B58B30 is the engine for the F30 340i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your F30 has a manual or an automatic gearbox. The flywheel or the flex plate and some sensors depend on it.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B58 Engines · Search B58B30 in the shop

How much is a replacement B58B30 engine for a BMW G11 740i?

A used B58B30 for the BMW G11 740i costs from about 4.150 € to 6.450 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B58B30 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B58 Engines · Search B58B30 in the shop

How much is a replacement B38A15 engine for a BMW F48 X1 sDrive18i?

A used B38A15 for the BMW F48 X1 sDrive18i costs from about 1.250 € to 2.100 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B38A15 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B38 Engines · Search B38A15 in the shop

Can you check if a B58B30 fits my car with my VIN?

Yes, and it is free. Send the 17-character VIN of your car and, if you have it, the gearbox code. We check the engine family, the build year window and the parts your car needs.

For the B58B30, we confirm that your car was built with this code or with a version that can take it. BMW used it in the BMW F30 340i, BMW G30 540i, BMW G11 740i, BMW G05 X5 xDrive40i and BMW G01 X3 M40i.

We only reserve an engine once the match is confirmed, so you never pay for the wrong unit. You can reach the Hamburg desk by email at autowerkeengines@gmail.com, or by phone and WhatsApp on +49 15510 030835, Monday to Friday, 9:00 to 16:00 CET.

You can also use the VIN check on our site. It reads the year, the make, the model and the engine from the public vehicle register.

See all B58 Engines · Search B58B30 in the shop

How much is a replacement B48B20 engine for a BMW F40 128ti?

A used B48B20 for the BMW F40 128ti costs from about 2.650 € to 4.200 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B48B20 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines · Search B48B20 in the shop

Can I put a BMW M57 / N57 / B58 engine in my BMW E90?

Yes. We sell conversion kits that fit the BMW M57 / N57 / B58 into the BMW E90. The kit replaces the Getrag 5-speed and GM 5L40, and works with the ZF 8HP, ZF GS6-53 and DCT.

You can buy the full package with an engine, or only the parts you need: gearbox conversion, transfer case adapter, clutch and flywheel and propshaft.

A swap like this needs a skilled workshop. Mounts, the adapter, the wiring and the engine computer, the cooling and the exhaust all have to work together. Check your local road rules for engine swaps before you start.

Tell us your BMW E90's year and current set-up, and we suggest the right parts. You can reach the Hamburg desk by email at autowerkeengines@gmail.com, or by phone and WhatsApp on +49 15510 030835, Monday to Friday, 9:00 to 16:00 CET.

See all BMW Gearbox Conversion Kits · Conversion guide

What is in the B58 BMW cooling and exhaust kit?

The B58 BMW cooling and exhaust kit includes: Radiator hoses made for this swap; Intercooler pipe set; Downpipe and flex section; Expansion tank adapter; Temperature sender adapter.

It is made for the BMW E46, BMW E36 and BMW E90 (1998–2013), and replaces the M54, N52 and N55. Gearbox set-ups we support are the ZF 8HP and ZF GS6-53.

This kit costs about 450 € to 740 €, depending on the exact listing. The engine is not included, so you can use your own B58B30 or buy one from our yard.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. If you are not sure which kit you need, tell us your vehicle, its year and its current engine and gearbox. We help for free.

See all B58 BMW Conversion Kits · Conversion guide

What is the difference between the B58B30M1 and other B58 engines?

The B58B30M1 makes 275 kW (374 HP) and 500 Nm. The other B58 engines are: B58B30 with 250 kW (340 HP) and 500 Nm (2015 to 2020).

Engines in one family share a basic block, but the turbo, the injection, the sensors and the engine computer can differ. A higher power version often has different pistons, a bigger turbo or a different fuel system.

This is why we ask for the exact code. Fitting a different version can work, but the wiring, the software and sometimes the gearbox must be changed to match.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B58 Engines · Search B58B30M1 in the shop

What comes with a used B38A15 engine?

Each B38A15 is sold as described on its own listing. The yard writes down the parts that are fitted to that unit, such as the turbo, the injectors, the manifolds or the alternator, so you know what arrives.

Some units are long engines with few ancillaries, others are more complete. If you need a part that is not listed, ask the desk. We often have the matching items in the yard.

Every engine is drained, sealed at each opening, strapped to a heat-treated pallet and shrink-wrapped, then photographed before it leaves the yard.

On delivery, the carrier brings the pallet to the kerb or a loading bay. Please have a forklift, a pallet truck or an engine crane ready.

See all B38 Engines · Search B38A15 in the shop

Can I put a B58B30 engine in my BMW E46?

Yes. We sell conversion kits that fit the B58B30 into the BMW E46. The kit replaces the M54, N52 and N55, and works with the ZF 8HP and ZF GS6-53.

You can buy the full package with an engine, or only the parts you need: complete conversion with engine, complete conversion, adapter plate, engine mount, wiring and ecu and cooling and exhaust.

A swap like this needs a skilled workshop. Mounts, the adapter, the wiring and the engine computer, the cooling and the exhaust all have to work together. Check your local road rules for engine swaps before you start.

Tell us your BMW E46's year and current set-up, and we suggest the right parts. You can reach the Hamburg desk by email at autowerkeengines@gmail.com, or by phone and WhatsApp on +49 15510 030835, Monday to Friday, 9:00 to 16:00 CET.

See all B58 BMW Conversion Kits · Conversion guide

Which years were BMW B48 engines made?

BMW built the B48 engines we list from about 2015 to 2025. The B48B20 ran from 2015 to 2025.

They went into chassis G20, G21, G30, G01, F30, F40 and G22. The exact year of a car matters, because BMW sometimes changed the engine version or its parts in the middle of a model's life.

Each listing in our yard names the engine year, so you can match it to the build date of your car.

Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines

How much is a replacement B48B20 engine for a BMW G01 X3 xDrive30i?

A used B48B20 for the BMW G01 X3 xDrive30i costs from about 2.650 € to 4.200 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B48B20 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B48 Engines · Search B48B20 in the shop

How much is a replacement B58B30M1 engine for a BMW G22 M440i?

A used B58B30M1 for the BMW G22 M440i costs from about 5.200 € to 7.950 € in our yard. The price depends on the year, the mileage and the parts that come with the engine.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. Inside the EU there is no import duty. Outside the EU, the receiver pays local duty and VAT.

A replacement engine is often much cheaper than rebuilding a damaged one, and much faster. The B58B30M1 you buy is photographed and checked in Hamburg before it is listed.

Eligible engines come with a 12 months warranty from the delivery date. It covers internal mechanical failure under normal use and correct fitting by a qualified mechanic or workshop. Not sure? Send us your VIN and your gearbox code. We match the engine family, the year window and the parts on the engine before anything is reserved, and the check is free.

See all B58 Engines · Search B58B30M1 in the shop

What is in the B58 BMW wiring and ecu kit?

The B58 BMW wiring and ecu kit includes: B58B30 patch loom for the BMW E46; ECU bridge connector; Immobiliser bypass or coded ECU; Sensor pinout sheet; Fuse and relay map.

It is made for the BMW E46, BMW E36 and BMW E90 (1998–2013), and replaces the M54, N52 and N55. Gearbox set-ups we support are the ZF 8HP and ZF GS6-53.

This kit costs about 500 € to 820 €, depending on the exact listing. The engine is not included, so you can use your own B58B30 or buy one from our yard.

Shipping is a flat 249 € per order. It is added once at checkout and printed on the invoice, so there is no extra fee later. If you are not sure which kit you need, tell us your vehicle, its year and its current engine and gearbox. We help for free.

See all B58 BMW Conversion Kits · Conversion guide

Glossary

• VANOS — BMW's variable camshaft timing system. It adjusts the intake camshaft (single VANOS) or both camshafts (double VANOS) to improve torque and emissions.
• Valvetronic — BMW's variable valve lift system. It controls engine load with the intake valves instead of a throttle plate, improving economy.
• Direct injection — Fuel is injected directly into the cylinder instead of the intake port. It improves efficiency but can cause carbon build-up on the intake valves.
• Wastegate — A valve that lets exhaust gas bypass the turbine to control boost pressure. Worn wastegates rattle and can cause boost faults.
• DPF — Diesel particulate filter. It traps soot and burns it off during regeneration, which needs longer journeys.
• EGR — Exhaust gas recirculation. It feeds some exhaust back into the intake to reduce NOx emissions but builds up soot.
• Common rail — A diesel injection system with a high-pressure fuel rail feeding all injectors. It allows precise, multiple injections per cycle.
• Long block — An engine with the block, head and internals but without most ancillaries such as manifolds, turbo, alternator or starter.
• Dressed engine — An engine with most ancillaries fitted, ready to install with fewer parts transferred.
• Compression test — A measurement of the pressure each cylinder builds when cranked. Even readings show healthy rings and valves.
• Leak-down test — A test that pressurises each cylinder and measures how much air escapes, showing where any leak is.
• LCI — Life Cycle Impulse, BMW's name for a mid-life update. Engines often change at the LCI.
• xDrive — BMW's all-wheel-drive system. xDrive cars often use a different sump and oil pickup.
• DME — Digital Motor Electronics, BMW's name for the engine control unit.
• CAS, FEM and BDC — The immobiliser and body modules that must be matched to the engine control unit on modern BMWs.
• Timing chain tensioner — A hydraulic or spring device that keeps the timing chain tight. Worn tensioners cause cold-start rattle.
• Rear-mounted timing chain — A timing chain at the gearbox end of the engine. Replacing it normally requires removing the engine.
• TU — Technical Update, BMW's suffix for a revised version of an engine.

Our verdict

The BMW G20 and G21 3 Series offers a wide choice of engines, and the right replacement depends on your exact model, build date and gearbox. Confirm the code with your VIN, choose a unit with known history, replace the known weak parts while it is out, and the car will be back on the road for years.

See every BMW G20 and G21 3 Series engine in stock, or ask the Hamburg desk to check your VIN.

Model-by-model engine guides

• BMW 330i (G20) engine: which one, problems and replacement
• BMW M340i (G20) engine: which one, problems and replacement
• BMW 320d (G20) engine: which one, problems and replacement
• BMW 318d (G20) engine: which one, problems and replacement