BMW built the M50B20 from 1990 to 1996. It is a 2.0 L naturally aspirated petrol inline-6 with 150 hp and 190 Nm, part of the M50 family. You will find it in the BMW E36 320i and BMW E34 520i.
This guide is about the M50B20 specifically: its specification, the cars that use it, how it differs from the other M50 versions, what to check, prices from our stock and fitment answers for each model. For the history of the whole family, read our M50 guide.
- Capacity and layout: 2.0 L, inline-6, naturally aspirated
- Output: 150 hp and 190 Nm
- Production: 1990–1996
- Fitted to: 2 models across 2 chassis generations
- In our stock: 4 units from 1.313,00 €
M50B20 specifications
| Item | Value |
|---|---|
| Engine code | M50B20 |
| Family | M50 |
| Capacity | 2.0 L |
| Layout | Inline-6 |
| Fuel | Petrol |
| Aspiration | Naturally aspirated |
| Power | 150 hp |
| Torque | 190 Nm |
| Specific output | 75 hp per litre |
| Production | 1990–1996 |
| Models | 2 |
Built from 1990 to 1996, the M50B20 displaces 2.0 L in an inline-6 layout and is naturally aspirated. It produces 150 hp and 190 Nm on petrol. That is about 75 hp and 95 Nm per litre, a strong figure for a road engine of its era. Within the M50 family, the M50B25 (192 hp) and M50TUB25 (192 hp) are more powerful, while the M502 (100 hp) and M503 (140 hp) are milder. It was fitted to the BMW E36 320i and BMW E34 520i.
What the code M50B20 means
- 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.
Which BMW models use the M50B20
| Model | Generation | Built |
|---|---|---|
| BMW E36 320i | third 3 Series | 1990–2000 |
| BMW E34 520i | third 5 Series | 1988–1996 |
In the E36 third 3 Series (1990–2000), the M50B20 powered the 320i. We have 1 M50B20 unit from E36 donor cars. All E36 engines
In the E34 third 5 Series (1988–1996), the M50B20 powered the 520i. We have 1 M50B20 unit from E34 donor cars. All E34 engines
M50B20 compared with other M50 versions
| Code | Capacity | Power | Torque | Years |
|---|---|---|---|---|
| M502 | 2.6 L | 100 hp | 180 Nm | 1954–1961 |
| M503 | 3.2 L | 140 hp | 240 Nm | 1956–1959 |
| M507 | 3.2 L | 150 hp | 240 Nm | 1956–1959 |
| M50B20 | 2.0 L | 150 hp | 190 Nm | 1990–1996 |
| M50B25 | 2.5 L | 192 hp | 245 Nm | 1990–1996 |
| M50TUB20 | 2.0 L | 150 hp | 190 Nm | 1992–1995 |
| M50TUB25 | 2.5 L | 192 hp | 245 Nm | 1992–1995 |
M50B20 or M50TUB20?
The M50TUB20 has the same 150 hp as the M50B20, from the same 2.0 L, and was built 1992–1995. Versions of the same size share the block and most mounting points, but the turbo or intake, injectors, software and sometimes the sump differ. Fitting one in place of the other usually means transferring parts and coding the engine control unit, so the simplest choice is the code your car left the factory with.
M50B20 or M507?
The M507 has the same 150 hp as the M50B20, from 3.2 L instead of 2.0 L, and was built 1956–1959. A different capacity means a different crankshaft, pistons or head, and different software. It can be fitted as an upgrade with the matching engine control unit and wiring, but it is a conversion rather than a straight replacement.
M50B20 or M503?
The M503 has 10 hp less than the M50B20 (140 against 150 hp), from 3.2 L instead of 2.0 L, and was built 1956–1959. A different capacity means a different crankshaft, pistons or head, and different software. It can be fitted as an upgrade with the matching engine control unit and wiring, but it is a conversion rather than a straight replacement.
Common M50B20 problems
The M50B20 shares its weak points with the rest of the M50 family. These are the faults to check on a used unit and on your own engine. The full explanation of each is in the M50 guide.
| Known fault | What to check |
|---|---|
| Cooling system | Check for a metal impeller water pump and a recent expansion tank. |
| VANOS seals (M50TU) | Listen for a rattle at the front of the head at idle and check for a flat spot below 3,000 rpm. |
| Crankcase ventilation valve | Check for oil in the intake boot and around the dipstick tube. |
| Oil filter housing gasket | Look for oil on the alternator side of the engine. |
| Valve cover gasket | Remove a coil and inspect the well. |
Cooling system. Plastic water pump impellers, thermostat housings and expansion tanks crack, and overheating can warp the head.
M50B20 maintenance
- 5W-40 or 10W-40 synthetic, about 6.5 litres with filter.
- Oil every 10,000 to 15,000 km; cooling system as a set every 100,000 km.
- Duplex lower chain and single upper chain at the front with hydraulic tensioner.
Will the M50B20 fit my car?
M50B20 prices
Across 4 M50B20 units in our stock today, prices start at 1.313,00 € and reach 3.133,00 €. The median — the price in the middle of the range — is 1.496,00 €.
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.
M50B20 engines in stock
Here is a selection of M50B20 engines currently on our shelves, photographed in the yard. Click any of them for the full photographs, mileage and specification.
BMW E34 520i M50B20 Complete Engine1.485,00 €
BMW E36 320i M50B20 Engine, Premium Grade3.133,00 €BMW M50B20 Engine1.313,00 €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 E36 320i M50B20 Engine, Premium Grade — 3.133,00 €, reduced from 3.600,00 €. 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.
Buying a used M50B20: checklist
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
Questions about the M50B20
How do I know a used M50B20 engine is in good shape?
The photos on each listing show the actual engine, not a stock picture. The yard checks the code, records what is bolted on, and seals the openings before the engine is offered. An inspection certificate for the unit can travel with the order when you ask for it.
When you look at a listing, check the recorded mileage, the year and the photos of the ports and the stamp. Ask for photos of anything you want to see closer. Ask the desk for more pictures of any listing. We are happy to show the stamp, the ports and the ancillaries before you decide.
On a petrol engine like the M50B20, a careful fitter will also look at the spark plugs, the coils and the timing side before the engine goes in.
If the engine fails inside under normal use, the warranty covers you. 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.
See all M50 Engines · Search M50B20 in the shop
Can you check if an M50B20 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 M50B20, we confirm that your car was built with this code or with a version that can take it. BMW used it in the BMW E36 320i and BMW E34 520i.
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 M50 Engines · Search M50B20 in the shop
Is the BMW M50B20 a diesel or petrol engine?
The M50B20 is a petrol engine. It is a 2.0 liter (1,991 cc) inline 6, DOHC, 24 valve unit with no turbo (naturally aspirated), and it was built to the Euro 1 emission standard.
The emission standard matters for registration and for low-emission zones in many cities. When you replace an engine with the same code, the car keeps the same paperwork and the same emission class.
Petrol versions need the correct catalytic converters and oxygen sensors on the car to stay legal and to keep the engine computer happy. Reuse the parts from your car if they are in good condition.
If you are not sure which version you need, send us your VIN. We tell you the right code for free.
See all M50 Engines · Search M50B20 in the shop
How much is a replacement M50B20 engine for a BMW E34 520i?
A used M50B20 for the BMW E34 520i costs from about 1.300 € to 2.200 € 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 M50B20 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 M50 Engines · Search M50B20 in the shop
What is the difference between the M50B20 and other M50 engines?
The M50B20 makes 110 kW (150 HP) and 190 Nm. The other M50 engines are: M50B25 with 141 kW (192 HP) and 245 Nm (1990 to 1995).
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 M50 Engines · Search M50B20 in the shop
What should I replace when I fit a used M50B20 engine?
A used engine lasts longest when it starts life in your car with fresh fluids and new seals. Fit a new oil filter and fresh oil of the grade BMW lists for this engine, and refill the coolant with the correct BMW antifreeze mix. Check the spark plugs and the ignition coils, and make sure the fuel lines are clean and tight before you crank the engine. Change the drive belt, the thermostat and the water pump seals if they look tired, because they are cheap while the engine is out.
Look at the engine mounts and the clutch or the torque converter while the engine is out. Old mounts can crack a new engine's brackets, and a worn clutch is much easier to change now.
Before the first start, turn the engine over without fuel until the oil pressure light goes out. Then let it idle, check for leaks, and drive gently for the first few hundred kilometres.
The warranty asks for fitting by a qualified mechanic and the correct oil, coolant and filters. Keep your receipts in case you ever need to make a claim.
See all M50 Engines · Search M50B20 in the shop
Will the M50B20 engine fit my BMW E34 520i?
Yes, if your BMW E34 520i was built with the M50B20. BMW used this 2.0 liter (1,991 cc) petrol engine with 110 kW (150 HP) in the E34 520i from about 1990 to 1995.
In our records the M50B20 is the engine for the E34 520i, which makes the match simple. Still, check the code on your old engine or send us your VIN.
Also tell us if your E34 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 M50 Engines · Search M50B20 in the shop
How much power and torque does the BMW M50B20 have?
From the factory the BMW M50B20 makes 110 kW (150 HP) and 190 Nm of torque. It is a 2.0 liter (1,991 cc) inline 6, DOHC, 24 valve petrol engine with no turbo (naturally aspirated).
Without a turbo, the power builds smoothly with the revs. A clean air intake, healthy ignition and the correct fuel are key to getting the full figure.
A used engine reaches its factory numbers when it is fitted with the matching engine computer and software, and serviced with the right oil and filters. If the engine computer from your car is a different version, a specialist may need to code it.
Every M50B20 on our site lists its year and mileage. If you want more photos or a short video of a unit, ask the desk and we send them before you pay.
See all M50 Engines · Search M50B20 in the shop
How much does a used BMW M50B20 engine cost?
A used BMW M50B20 engine in our yard usually costs between 1.300 € and 2.200 €. The exact price depends on the year, the mileage and the parts that come with the engine.
Our units show recorded mileage from about 22,000 km up to around 200,000 km. Lower mileage and more ancillaries mean a higher price. Each listing shows its own price, and the price you see is the price you pay. Prices include VAT for private buyers.
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 order a gearbox or a second engine on the same order, the fee is still charged once.
Inside the EU there is no import duty. For the UK and other non-EU countries, import duty and local VAT are paid by the receiver, and we supply a commercial invoice.
See all M50 Engines · Search M50B20 in the shop
What comes with a used M50B20 engine?
Each M50B20 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 M50 Engines · Search M50B20 in the shop
How much is a replacement M50B20 engine for a BMW E36 320i?
A used M50B20 for the BMW E36 320i costs from about 1.300 € to 2.200 € 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 M50B20 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 M50 Engines · Search M50B20 in the shop
Which cars use the BMW M50B20 engine?
BMW fitted the M50B20 to the BMW E36 320i and BMW E34 520i. These cars were built with this engine from about 1990 to 1995.
The badge on the boot is not enough to be sure. The same model name can hide two different engines, for example after a facelift or a change in emission rules. Always read the engine code stamped on the block, or look it up with your VIN.
Other engines in the same M50 family are the M50B25 (192 HP). They look alike but differ in power, parts and electronics, so they are not always a direct swap.
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 M50 Engines · Search M50B20 in the shop
How long does delivery of an M50B20 engine take?
Orders confirmed before 14:00 CET on a working day leave Hamburg the same day. Later and weekend orders leave the next working day. Delivery to the Netherlands, Belgium, Germany, France, Luxembourg and Denmark takes 1 to 3 working days.
Spain, Italy, Portugal, Poland, Czechia, Austria, Ireland, the Nordics and the Baltics take 2 to 5 working days. Greek and Spanish islands, Malta, Cyprus and remote areas take 4 to 8 working days. The UK and other countries outside the EU are quoted one by one.
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. Every engine is drained, sealed at each opening, strapped to a heat-treated pallet and shrink-wrapped, then photographed before it leaves the yard.
You get a tracking number when the pallet is collected. Check the wrapping before you sign, and note any damage on the paperwork.
See all M50 Engines · Search M50B20 in the shop
What is the BMW M50B20 engine?
The BMW M50B20 is a 2.0 liter (1,991 cc) petrol engine from the M50 family. It has an inline 6, DOHC, 24 valve layout with no turbo (naturally aspirated), and makes 110 kW (150 HP) with 190 Nm of torque. BMW built it from 1990 to 1995 and it meets the Euro 1 emission standard.
You find the M50B20 in the BMW E36 320i and BMW E34 520i. What we list: BMW M50 24-valve petrol engines for E36 320i and 325i.
At Autowerke Engines every M50B20 is a real used engine from our yard in Hamburg. Before a unit is listed, the yard checks the engine code against the listing, writes down the parts fitted to it, seals every opening and photographs the real engine you will receive. Each listing shows the year, the mileage and the price, so you can compare units side by side.
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 M50 Engines · Search M50B20 in the shop
Will the M50B20 engine fit my BMW E36 320i?
Yes, if your BMW E36 320i was built with the M50B20. BMW used this 2.0 liter (1,991 cc) petrol engine with 110 kW (150 HP) in the E36 320i from about 1990 to 1995.
In our records the M50B20 is the engine for the E36 320i, which makes the match simple. Still, check the code on your old engine or send us your VIN.
Also tell us if your E36 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 M50 Engines · Search M50B20 in the shop
Does a used M50B20 engine come with a warranty?
Yes. 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.
The warranty does not cover damage from wrong fitting, overheating, low oil, wrong fluids or fuel, engines that were opened or modified without our approval, or labour and towing costs.
To claim, send us your order number, a short description of the problem, photos or a video, and a mechanic's report if we ask for one. If the claim is approved, we repair, replace or refund the engine.
Keep the receipts for the fitting, the oil and the filters. They make any claim quick and simple.
See all M50 Engines · Search M50B20 in the shop
Delivery, warranty and payment
Every M50B20 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.
