BMW M70B50 engine: specs, problems and prices

The M70B50 is a 5.0 L petrol V12 from BMW's M70 family, built 1987–1994 and rated at 300 hp and 450 Nm. It powered the BMW E32 750i and BMW E31 850i.

This guide is about the M70B50 specifically: its specification, the cars that use it, how it differs from the other M70 versions, what to check, prices from our stock and fitment answers for each model. For the history of the whole family, read our M70 and M73 guide.

• Capacity and layout: 5.0 L, V12, naturally aspirated
• Output: 300 hp and 450 Nm
• Production: 1987–1994
• Fitted to: 2 models across 2 chassis generations
• In our stock: ask the desk for the next arrival

M70B50 specifications

The M70B50 is a 5.0 L V12 petrol engine, naturally aspirated, rated at 300 hp and 450 Nm. BMW built it from 1987 to 1994. That is about 60 hp and 90 Nm per litre, a relaxed tune aimed at torque, durability and economy. It was fitted to the BMW E32 750i and BMW E31 850i.

What the code M70B50 means

• M marks an M-series code, the naming BMW used for its engine families up to the early 2000s.
• 70 is the family number.
• B stands for petrol (from the German Benzin).
• 50 is the capacity in decilitres, so 5.0 litres.

Which BMW models use the M70B50

In the E32 second 7 Series (1986–1994), the M70B50 powered the 750i. Engines from other models fit the E32 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E32 engines

In the E31 8 Series (1989–1999), the M70B50 powered the 850i. Engines from other models fit the E31 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E31 engines

Common M70B50 problems

The M70B50 shares its weak points with the rest of the M70 family. These are the faults to check on a used unit and on your own engine. The full explanation of each is in the M70 and M73 guide.

Wiring harness. Harness insulation becomes brittle with heat and age.

M70B50 maintenance

• 5W-40 or 10W-40 synthetic, about 7.5 litres.
• Oil every 10,000 km or yearly.
• Single-row timing chains, one per bank.

Will the M70B50 fit my car?

M70B50 prices

We do not have an M70B50 on the shelf at the moment. Send us your VIN or the code you need and the desk will tell you when the next unit arrives and what it will cost.

Buying a used M70B50: checklist

1. 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.
2. 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.
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. 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.
5. 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.
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. Originality and numbers. For collectible cars, the engine number and correct ancillaries add value. Photograph the stamp and keep it with the car's documents.
8. Both cylinder banks and both ECUs. V12 engines often use separate management for each bank. Read faults from both and compare compression across all twelve cylinders.

Questions about the M70B50

Are there other versions of the BMW M70B50?

In our yard the M70B50 is the only listed version of the M70 family. It makes 220 kW (300 HP) and 450 Nm, and was built from 1987 to 1994.

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.

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Will the M70B50 engine fit my BMW E32 750i?

Yes, if your BMW E32 750i was built with the M70B50. BMW used this 5.0 liter (4,988 cc) petrol engine with 220 kW (300 HP) in the E32 750i from about 1987 to 1994.

In our records the M70B50 is the engine for the E32 750i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your E32 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.

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Is the BMW M70B50 a diesel or petrol engine?

The M70B50 is a petrol engine. It is a 5.0 liter (4,988 cc) V12, SOHC, 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.

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Which cars use the BMW M70B50 engine?

BMW fitted the M70B50 to the BMW E32 750i and BMW E31 850i. These cars were built with this engine from about 1987 to 1994.

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.

The M70B50 is the only M70 version we list, which makes it easy to pick, but the wiring and the engine computer still need to match 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.

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How much is a replacement M70B50 engine for a BMW E32 750i?

A used M70B50 for the BMW E32 750i costs from about 3.850 € to 5.950 € 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 M70B50 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.

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What comes with a used M70B50 engine?

Each M70B50 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.

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Does a used M70B50 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.

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How long does delivery of an M70B50 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.

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How much is a replacement M70B50 engine for a BMW E31 850i?

A used M70B50 for the BMW E31 850i costs from about 3.850 € to 5.950 € 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 M70B50 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 M70 Engines · Search M70B50 in the shop

Will the M70B50 engine fit my BMW E31 850i?

Yes, if your BMW E31 850i was built with the M70B50. BMW used this 5.0 liter (4,988 cc) petrol engine with 220 kW (300 HP) in the E31 850i from about 1987 to 1994.

In our records the M70B50 is the engine for the E31 850i, which makes the match simple. Still, check the code on your old engine or send us your VIN.

Also tell us if your E31 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 M70 Engines · Search M70B50 in the shop

What should I replace when I fit a used M70B50 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.

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Can you check if an M70B50 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 M70B50, we confirm that your car was built with this code or with a version that can take it. BMW used it in the BMW E32 750i and BMW E31 850i.

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.

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How much power and torque does the BMW M70B50 have?

From the factory the BMW M70B50 makes 220 kW (300 HP) and 450 Nm of torque. It is a 5.0 liter (4,988 cc) V12, SOHC, 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 M70B50 on our site lists its year and mileage. Ask the desk for more pictures of any listing. We are happy to show the stamp, the ports and the ancillaries before you decide.

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How do I know a used M70B50 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 M70B50, 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 M70 Engines · Search M70B50 in the shop

What is the BMW M70B50 engine?

The BMW M70B50 is a 5.0 liter (4,988 cc) petrol engine from the M70 family. It has a V12, SOHC, 24 valve layout with no turbo (naturally aspirated), and makes 220 kW (300 HP) with 450 Nm of torque. BMW built it from 1987 to 1994 and it meets the Euro 1 emission standard.

You find the M70B50 in the BMW E32 750i and BMW E31 850i. What we list: BMW M70 5.0 V12 engines for the E32 750i and E31 850i.

At Autowerke Engines every M70B50 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 M70 Engines · Search M70B50 in the shop

How much does a used BMW M70B50 engine cost?

A used BMW M70B50 engine in our yard usually costs between 3.850 € and 5.950 €. 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.

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Delivery, warranty and payment

Before an M70B50 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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