The M30B25 is a 2.5 L petrol inline-6 from BMW's M30 family, built 1968–1994 and rated at 150 hp and 215 Nm. It powered the BMW E12 525, BMW E28 525i and BMW E24 525i.
This guide is about the M30B25 specifically: its specification, the cars that use it, how it differs from the other M30 versions, what to check, prices from our stock and fitment answers for each model. For the history of the whole family, read our M30 guide.
- Capacity and layout: 2.5 L, inline-6, naturally aspirated
- Output: 150 hp and 215 Nm
- Production: 1968–1994
- Fitted to: 3 models across 3 chassis generations
- In our stock: ask the desk for the next arrival
M30B25 specifications
| Item | Value |
|---|---|
| Engine code | M30B25 |
| Family | M30 |
| Capacity | 2.5 L |
| Layout | Inline-6 |
| Fuel | Petrol |
| Aspiration | Naturally aspirated |
| Power | 150 hp |
| Torque | 215 Nm |
| Specific output | 60 hp per litre |
| Production | 1968–1994 |
| Models | 3 |
Built from 1968 to 1994, the M30B25 displaces 2.5 L in an inline-6 layout and is naturally aspirated. It produces 150 hp and 215 Nm on petrol. That is about 60 hp and 86 Nm per litre, a relaxed tune aimed at torque, durability and economy. Within the M30 family, the M30B28 (184 hp), M30B30 (188 hp) and M30B32 (197 hp) are more powerful. It was fitted to the BMW E12 525, BMW E28 525i and BMW E24 525i.
What the code M30B25 means
- M marks an M-series code, the naming BMW used for its engine families up to the early 2000s.
- 30 is the family number.
- B stands for petrol (from the German Benzin).
- 25 is the capacity in decilitres, so 2.5 litres.
Which BMW models use the M30B25
| Model | Generation | Built |
|---|---|---|
| BMW E12 525 | first 5 Series | 1972–1981 |
| BMW E28 525i | second 5 Series | 1981–1988 |
| BMW E24 525i | first 6 Series | 1976–1989 |
In the E12 first 5 Series (1972–1981), the M30B25 powered the 525. Engines from other models fit the E12 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E12 engines
In the E28 second 5 Series (1981–1988), the M30B25 powered the 525i. Engines from other models fit the E28 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E28 engines
In the E24 first 6 Series (1976–1989), the M30B25 powered the 525i. Engines from other models fit the E24 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E24 engines
M30B25 compared with other M30 versions
| Code | Capacity | Power | Torque | Years |
|---|---|---|---|---|
| M30B25 | 2.5 L | 150 hp | 215 Nm | 1968–1994 |
| M30B28 | 2.8 L | 184 hp | 240 Nm | 1968–1994 |
| M30B30 | 3.0 L | 188 hp | 260 Nm | 1968–1994 |
| M30B32 | 3.2 L | 197 hp | 285 Nm | 1976–1984 |
| M30B34 | 3.4 L | 218 hp | 310 Nm | 1982–1994 |
| M30B35 | 3.5 L | 211 hp | 305 Nm | 1988–1994 |
M30B25 or M30B28?
The M30B28 has 34 hp more than the M30B25 (184 against 150 hp), from 2.8 L instead of 2.5 L, and was built 1968–1994. 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.
M30B25 or M30B30?
The M30B30 has 38 hp more than the M30B25 (188 against 150 hp), from 3.0 L instead of 2.5 L, and was built 1968–1994. 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.
M30B25 or M30B32?
The M30B32 has 47 hp more than the M30B25 (197 against 150 hp), from 3.2 L instead of 2.5 L, and was built 1976–1984. 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 M30B25 problems
The M30B25 shares its weak points with the rest of the M30 family. These are the faults to check on a used unit and on your own engine. The full explanation of each is in the M30 guide.
| Known fault | What to check |
|---|---|
| Head gasket and cracked heads | Do a compression test and look for bubbles in the expansion tank with the engine running. |
| Cooling system age | Check the fan clutch resistance hot and the radiator for blocked cores. |
| Rocker arm wear | Inspect the cam surface with the valve cover off. |
| Timing chain tensioner | Listen for a cold-start rattle at the front of the engine. |
| Oil pressure sender and leaks | Check for oil around the filter housing and the bellhousing. |
Timing chain tensioner. The duplex chain lasts, but the tensioner piston and guide rails wear on high-mileage units.
M30B25 maintenance
- 10W-40 or 15W-40, about 5.75 litres with filter on most versions.
- Oil every 7,500 km; valve clearances every 15,000 to 20,000 km.
- Duplex timing chain at the front with a hydraulic tensioner; no service interval.
Will the M30B25 fit my car?
Will the M30B25 fit my BMW E12 525?
Yes, the BMW E12 525 left the factory with the M30B25, so an M30B25 from another car is the direct replacement. The first 5 Series was built 1972–1981, and the M30B25 was produced 1968–1994, 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 E12 525?
We do not have an M30B25 on the shelf for the E12 525 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 M30B25 fit my BMW E28 525i?
Yes, the BMW E28 525i left the factory with the M30B25, so an M30B25 from another car is the direct replacement. The second 5 Series was built 1981–1988, and the M30B25 was produced 1968–1994, 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 E28 525i?
We do not have an M30B25 on the shelf for the E28 525i 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 M30B25 fit my BMW E24 525i?
Yes, the BMW E24 525i left the factory with the M30B25, so an M30B25 from another car is the direct replacement. The first 6 Series was built 1976–1989, and the M30B25 was produced 1968–1994, 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 E24 525i?
We do not have an M30B25 on the shelf for the E24 525i 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.
M30B25 prices
We do not have an M30B25 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 M30B25: checklist
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
Questions about the M30B25
Which cars use the BMW M30B34 engine?
BMW fitted the M30B34 to the BMW E28 M5 and BMW E24 M635CSi. These cars were built with this engine from about 1985 to 1988.
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 M30 family are the M30B35 (211 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 M30 Engines · Search M30B34 in the shop
What comes with a used M30B35 engine?
Each M30B35 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 M30 Engines · Search M30B35 in the shop
Can you check if an M30B34 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 M30B34, we confirm that your car was built with this code or with a version that can take it. BMW used it in the BMW E28 M5 and BMW E24 M635CSi.
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 M30 Engines · Search M30B34 in the shop
How much is a replacement M30B35 engine for a BMW E34 535i?
A used M30B35 for the BMW E34 535i costs from about 1.800 € to 2.950 € 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 M30B35 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 M30 Engines · Search M30B35 in the shop
Will the M30B35 engine fit my BMW E24 635CSi?
Yes, if your BMW E24 635CSi was built with the M30B35. BMW used this 3.5 liter (3,430 cc) petrol engine with 155 kW (211 HP) in the E24 635CSi from about 1982 to 1993.
In our records the M30B35 is the engine for the E24 635CSi, which makes the match simple. Still, check the code on your old engine or send us your VIN.
Also tell us if your E24 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 M30 Engines · Search M30B35 in the shop
How much power and torque does the BMW M30B34 have?
From the factory the BMW M30B34 makes 160 kW (218 HP) and 310 Nm of torque. It is a 3.4 liter (3,430 cc) inline 6, SOHC, 12 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 M30B34 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.
See all M30 Engines · Search M30B34 in the shop
How long does delivery of an M30B34 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 M30 Engines · Search M30B34 in the shop
What is the BMW M30B35 engine?
The BMW M30B35 is a 3.5 liter (3,430 cc) petrol engine from the M30 family. It has an inline 6, SOHC, 12 valve layout with no turbo (naturally aspirated), and makes 155 kW (211 HP) with 305 Nm of torque. BMW built it from 1982 to 1993 and it meets the Euro 1 emission standard.
You find the M30B35 in the BMW E28 535i, BMW E34 535i, BMW E24 635CSi, BMW E23 735i and BMW E32 735i. What we list: BMW M30 big-six petrol engines for E28, E24, E23 and E34.
At Autowerke Engines every M30B35 is a real used engine from our yard in Hamburg. Each engine in the yard is inspected in Hamburg. The code is matched to the listing, the parts on the engine are recorded, the openings are sealed and the real unit is photographed. 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 M30 Engines · Search M30B35 in the shop
How much is a replacement M30B34 engine for a BMW E24 M635CSi?
A used M30B34 for the BMW E24 M635CSi 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 M30B34 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 M30 Engines · Search M30B34 in the shop
How much does a used BMW M30B35 engine cost?
A used BMW M30B35 engine in our yard usually costs between 1.800 € and 2.950 €. 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.
See all M30 Engines · Search M30B35 in the shop
How much is a replacement M30B35 engine for a BMW E24 635CSi?
A used M30B35 for the BMW E24 635CSi costs from about 1.800 € to 2.950 € 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 M30B35 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 M30 Engines · Search M30B35 in the shop
What should I replace when I fit a used M30B35 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 M30 Engines · Search M30B35 in the shop
Delivery, warranty and payment
Every M30B25 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.
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.
