BMW 320i (E36) engine: which one, problems and replacement

The BMW 320i in the third 3 Series generation (E36, built 1990–2000) was built with 3 different engines over its life: the M50B20 (150 hp, 1990–1996), the M50TUB20 (150 hp, 1992–1995) and the M52B20 (150 hp, 1994–2000).

This guide tells you which engine your 320i has, what goes wrong with it, what a replacement costs from our stock and what else to plan for when you fit one.

• Generation: third 3 Series, 1990–2000
• Body styles: E36 (saloon, Touring, coupé, convertible, Compact)
• Engines: M50B20, M50TUB20, M52B20
• Output: 150 hp
• Replacement engines in stock: 12 from 907,00 €

Which engine is in your 320i?

M50B20 in the 320i

The M50B20 was used in the E36 320i, built 1990–1996. It is a 2.0 L naturally aspirated petrol inline-6 with 150 hp and 190 Nm. It has the same output as the M50TUB20 and M52B20, so the build date decides which one your car has.

Reading the code: M marks an M-series code, the naming BMW used for its engine families up to the early 2000s; 50 is the family number; B stands for petrol (from the German Benzin); 20 is the capacity in decilitres, so 2.0 litres.

M50TUB20 in the 320i

The M50TUB20 was used in the E36 320i, built 1992–1995. It is a 2.0 L naturally aspirated petrol inline-6 with 150 hp and 190 Nm. It has the same output as the M50B20 and M52B20, so the build date decides which one your car has.

M52B20 in the 320i

The M52B20 was used in the E36 320i, built 1994–2000. It is a 2.0 L naturally aspirated petrol inline-6 with 150 hp and 190 Nm. It has the same output as the M50B20 and M50TUB20, so the build date decides which one your car has.

Reading the code: M marks an M-series code, the naming BMW used for its engine families up to the early 2000s; 52 is the family number; B stands for petrol (from the German Benzin); 20 is the capacity in decilitres, so 2.0 litres.

320i engines by model year

The engine changed 4 times during the E36 run, in 1992, 1994, 1996 and 1997. Changes usually come with BMW's mid-life update (LCI) or a new emissions standard, so a car registered early in a year can still have the older engine. The VIN settles it.

Other cars with the same engine as the 320i

A replacement engine does not have to come from another 320i. These models left the factory with the same engine code, so a unit from any of them is a candidate donor once the sump, mounts and ancillaries are matched to your car.

M50B20: BMW E34 520i.

M50TUB20: BMW E34 520i.

M52B20: BMW E39 520i, BMW Z3 2.0.

How to confirm your engine code

Because the 320i used more than one engine, the badge alone does not tell you which one your car has. The build date is the first clue; the VIN is the proof. Send us the last seven characters of the VIN and we read the engine code from BMW's records, or look for the code stamped on the block. How to find your BMW engine code.

Known 320i engine problems

M50B20 and M50TUB20 (M50 family)

The M50B20 and M50TUB20 in the 320i share the known weak points of the M50 family. Full M50 guide.

Cooling system. Plastic water pump impellers, thermostat housings and expansion tanks crack, and overheating can warp the head.

VANOS seals (M50TU). The VANOS piston seals harden and the engine loses low-down torque and idles roughly.

Crankcase ventilation valve. The CCV valve can freeze or clog, pressurising the crankcase and pushing oil past seals.

Oil filter housing gasket. The gasket hardens and leaks oil down the side of the block.

Valve cover gasket. A common leak that also lets oil into the spark plug wells.

M52B20 (M52 family)

The M52B20 in the 320i shares the known weak points of the M52 family. Full M52 guide.

Nikasil bore wear. Early Nikasil engines run poorly when high-sulphur fuel damages the bore coating. Low compression and hard hot starts are the symptoms.

Cooling system. Plastic water pump impellers, thermostat housings and radiator necks crack.

VANOS seals and solenoids. Hardened seals cause rough idle and a loss of torque; double VANOS units also rattle.

DISA valve (M52TU). The flap inside the DISA valve can break and be drawn into the engine.

Crankcase ventilation. A blocked CCV causes oil consumption and leaks.

Symptoms to watch for on the 320i

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.

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.

Hard starting when warm and low compression. On engines with Nikasil bores, the bore coating may be damaged. A leak-down test confirms it.

Looking after the 320i engine

M50 engines

• Oil: 5W-40 or 10W-40 synthetic, about 6.5 litres with filter.
• Service interval: Oil every 10,000 to 15,000 km; cooling system as a set every 100,000 km.
• Timing drive: Duplex lower chain and single upper chain at the front with hydraulic tensioner.
• Workshop notes: Hydraulic lifters, no valve adjustment. Refresh VANOS seals when fitting a used M50TU.

M52 engines

• Oil: 5W-30 or 5W-40 synthetic to BMW Longlife standard, about 6.5 litres with filter.
• Service interval: Oil every 10,000 to 15,000 km; VANOS seals and cooling every 100,000 km.
• Timing drive: Duplex lower and single upper chains at the front with hydraulic tensioner.
• Workshop notes: Ask whether the block is Nikasil or Alusil. Engines built from late 1998 use Alusil.

Buying a used engine for the 320i: checklist

1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. Bore coating. Early engines with Nikasil bores can be damaged by high-sulphur fuel. A compression or leak-down test is the only reliable check; units with Alusil or iron bores are not affected.
9. Plastic cooling parts. Expansion tanks, thermostat housings and water pump impellers made of plastic crack with age. Plan to replace them when the engine is fitted.

BMW 320i replacement engine cost

Our 320i engine stock runs to 12 units, priced from 907,00 € to 3.133,00 € with a median of 1.414,00 €.

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.

3 of these come from E36 donor cars, priced from 937,00 € to 3.133,00 €. An engine from the same body is the most direct swap because the sump, mounts and ancillaries already match.

On top of the engine, budget for the workshop's labour and the parts that are best replaced while the engine is out: engine mounts, the rear main seal, cooling parts, a clutch or converter seal, fluids and filters.

Replacement engines in stock for the 320i

Here is a selection of 320i engines currently on our shelves, photographed in the yard. Click any of them for the full photographs, mileage and specification.

BMW M50B20 Engine1.496,00 €BMW E36 320i M50TUB20 Complete Engine937,00 €BMW E34 520i M50B20 Complete Engine1.485,00 €BMW M50B20 Engine1.313,00 €BMW E39 520i M52B20 Complete Engine1.320,00 €BMW Z3 2.0 M52B20 Complete Engine1.311,00 €BMW M50TUB20 Engine907,00 €BMW E34 520i M50TUB20 Complete Engine928,00 €

BMW M50B20 Engine — 1.496,00 €, reduced from 2.000,00 €. It comes from a recorded donor car, and 28 units are available. We can confirm fitment against your VIN the same day.

BMW E36 320i M50TUB20 Complete Engine — 937,00 €, reduced from 1.500,00 €. It comes from a recorded donor car, and 21 units are available. The listing shows every side of the engine and the fitted parts.

BMW E34 520i M50B20 Complete Engine — 1.485,00 €, reduced from 2.000,00 €. It comes from a recorded donor car, and 27 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW M50B20 Engine — 1.313,00 €, reduced from 1.700,00 €. It comes from a recorded donor car, and 14 units are available. We can confirm fitment against your VIN the same day.

BMW E39 520i M52B20 Complete Engine — 1.320,00 €, reduced from 1.900,00 €. It comes from a recorded donor car, and 8 units are available. Ask the desk for compression figures or extra photographs before you order.

BMW Z3 2.0 M52B20 Complete Engine — 1.311,00 €, reduced from 1.900,00 €. It comes from a recorded donor car, and 27 units are available. We can confirm fitment against your VIN the same day.

BMW M50TUB20 Engine — 907,00 €, reduced from 1.500,00 €. It comes from a recorded donor car, and 8 units are available. The listing shows every side of the engine and the fitted parts.

BMW E34 520i M50TUB20 Complete Engine — 928,00 €, reduced from 1.500,00 €. It comes from a recorded donor car, and 17 units are available. Ask the desk for compression figures or extra photographs before you order.

Will it fit my 320i?

Will the M50TUB20 fit my BMW E36 320i?

Yes, the BMW E36 320i left the factory with the M50TUB20, so an M50TUB20 from another car is the direct replacement. The third 3 Series was built 1990–2000, and the M50TUB20 was produced 1992–1995, 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 E36 320i?

We have 1 M50TUB20 engine from E36 donor cars, priced from 937,00 €. 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 M52B20 fit my BMW E36 320i?

Yes, the BMW E36 320i left the factory with the M52B20, so an M52B20 from another car is the direct replacement. The third 3 Series was built 1990–2000, and the M52B20 was produced 1994–2000, 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 E36 320i?

We have 1 M52B20 engine from E36 donor cars, priced from 3.000,00 €. 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 swaps and upgrades for the 320i

These engines were fitted to other versions of the E36 at the factory, which makes them the most practical upgrades: the body was designed around them and many parts are shared.

Can I fit the M52B25 in my 320i?

Yes, it is one of the more common upgrades. Both are petrol inline-6 engines, so the mounting points are similar, but the M52B25 needs its own wiring and engine control unit, the matching gearbox or clutch, and often a different sump, cooling and exhaust. The gain is 20 hp and 55 Nm. In Germany and most of Europe an engine swap must be inspected and registered.

Can I fit the M50B25 in my 320i?

Yes, it is one of the more common upgrades. Both are petrol inline-6 engines, so the mounting points are similar, but the M50B25 needs its own wiring and engine control unit, the matching gearbox or clutch, and often a different sump, cooling and exhaust. The gain is 42 hp and 55 Nm. In Germany and most of Europe an engine swap must be inspected and registered.

Can I fit the M50TUB25 in my 320i?

Yes, it is one of the more common upgrades. Both are petrol inline-6 engines, so the mounting points are similar, but the M50TUB25 needs its own wiring and engine control unit, the matching gearbox or clutch, and often a different sump, cooling and exhaust. The gain is 42 hp and 55 Nm. In Germany and most of Europe an engine swap must be inspected and registered.

Fitting a replacement engine in the 320i

1. 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.
2. Reset VANOS adaptations. Clear the VANOS adaptations so the ECU learns the camshaft positions of the new engine.
3. 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.
4. 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.
5. 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.
6. 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.

The full fitting and first-start procedure.

Delivery, warranty and payment

Before a 320i engine leaves our Hamburg yard it is drained of oil and coolant, every opening is sealed, and it is strapped to a pallet and wrapped. We send photographs of the packed unit and the tracking details.

Delivery is door to door and included in the price. Most European addresses receive the engine within five to ten working days; Germany and its neighbours are usually faster.

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.

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