BMW built the M52B25 from 1995 to 2000. It is a 2.5 L naturally aspirated petrol inline-6 with 170 hp and 245 Nm, part of the M52 family. You will find it in the BMW E36 323i, BMW E39 523i and BMW E46 323i.
This guide is about the M52B25 specifically: its specification, the cars that use it, how it differs from the other M52 versions, what to check, prices from our stock and fitment answers for each model. For the history of the whole family, read our M52 guide.
- Capacity and layout: 2.5 L, inline-6, naturally aspirated
- Output: 170 hp and 245 Nm
- Production: 1995–2000
- Fitted to: 3 models across 3 chassis generations
- In our stock: 6 units from 1.413,00 €
M52B25 specifications
| Item | Value |
|---|---|
| Engine code | M52B25 |
| Family | M52 |
| Capacity | 2.5 L |
| Layout | Inline-6 |
| Fuel | Petrol |
| Aspiration | Naturally aspirated |
| Power | 170 hp |
| Torque | 245 Nm |
| Specific output | 68 hp per litre |
| Production | 1995–2000 |
| Models | 3 |
Built from 1995 to 2000, the M52B25 displaces 2.5 L in an inline-6 layout and is naturally aspirated. It produces 170 hp and 245 Nm on petrol. That is about 68 hp and 98 Nm per litre, a relaxed tune aimed at torque, durability and economy. Within the M52 family, the M52B28 (193 hp) and M52TUB28 (193 hp) are more powerful, while the M52B20 (150 hp) is milder. It was fitted to the BMW E36 323i, BMW E39 523i and BMW E46 323i.
What the code M52B25 means
- 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).
- 25 is the capacity in decilitres, so 2.5 litres.
Which BMW models use the M52B25
| Model | Generation | Built |
|---|---|---|
| BMW E36 323i | third 3 Series | 1990–2000 |
| BMW E39 523i | fourth 5 Series | 1995–2004 |
| BMW E46 323i | fourth 3 Series | 1997–2006 |
In the E36 third 3 Series (1990–2000), the M52B25 powered the 323i. We have 2 M52B25 units from E36 donor cars. All E36 engines
In the E39 fourth 5 Series (1995–2004), the M52B25 powered the 523i. We have 1 M52B25 unit from E39 donor cars. All E39 engines
In the E46 fourth 3 Series (1997–2006), the M52B25 powered the 323i. We have 1 M52B25 unit from E46 donor cars. All E46 engines
M52B25 compared with other M52 versions
| Code | Capacity | Power | Torque | Years |
|---|---|---|---|---|
| M52B20 | 2.0 L | 150 hp | 190 Nm | 1994–2000 |
| M52B25 | 2.5 L | 170 hp | 245 Nm | 1995–2000 |
| M52B28 | 2.8 L | 193 hp | 280 Nm | 1995–2000 |
| M52TUB28 | 2.8 L | 193 hp | 280 Nm | 1998–2000 |
M52B25 or M52B20?
The M52B20 has 20 hp less than the M52B25 (150 against 170 hp), from 2.0 L instead of 2.5 L, and was built 1994–2000. 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.
M52B25 or M52B28?
The M52B28 has 23 hp more than the M52B25 (193 against 170 hp), from 2.8 L instead of 2.5 L, and was built 1995–2000. 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.
M52B25 or M52TUB28?
The M52TUB28 has 23 hp more than the M52B25 (193 against 170 hp), from 2.8 L instead of 2.5 L, and was built 1998–2000. 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 M52B25 problems
The M52B25 shares its weak points with the rest of the M52 family. These are the faults to check on a used unit and on your own engine. The full explanation of each is in the M52 guide.
| Known fault | What to check |
|---|---|
| Nikasil bore wear | A compression or leak-down test is the only reliable check; Alusil and iron-block units are not affected. |
| Cooling system | Look at the date of the last cooling refresh and check for a metal impeller. |
| VANOS seals and solenoids | Listen for a diesel-like rattle at idle and check for torque loss low down. |
| DISA valve (M52TU) | Remove the DISA valve and check the flap pin for play. |
| Crankcase ventilation | Look for oil in the intake and smoke on start. |
Crankcase ventilation. A blocked CCV causes oil consumption and leaks.
M52B25 maintenance
- 5W-30 or 5W-40 synthetic to BMW Longlife standard, about 6.5 litres with filter.
- Oil every 10,000 to 15,000 km; VANOS seals and cooling every 100,000 km.
- Duplex lower and single upper chains at the front with hydraulic tensioner.
Will the M52B25 fit my car?
M52B25 prices
Across 6 M52B25 units in our stock today, prices start at 1.413,00 € and reach 3.099,00 €. The median — the price in the middle of the range — is 1.565,00 €.
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.
M52B25 engines in stock
Here is a selection of M52B25 engines currently on our shelves, photographed in the yard. Click any of them for the full photographs, mileage and specification.
BMW E36 325i M52B25 Engine 19971.413,00 €
BMW M52B25 Engine1.640,00 €
BMW E46 323i M52B25 Complete Engine1.565,00 €
BMW E39 523i M52B25 Complete Engine1.502,00 €BMW E36 325i M52B25 Engine 1997 — 1.413,00 €, reduced from 2.000,00 €. It comes from a 1997 donor car, and 27 units are available. The listing shows every side of the engine and the fitted parts.
BMW M52B25 Engine — 1.640,00 €, reduced from 2.000,00 €. It comes from a recorded donor car, and 24 units are available. We can confirm fitment against your VIN the same day.
BMW E46 323i M52B25 Complete Engine — 1.565,00 €, reduced from 2.100,00 €. It comes from a recorded donor car, and 25 units are available. We can confirm fitment against your VIN the same day.
BMW E39 523i M52B25 Complete Engine — 1.502,00 €, reduced from 2.100,00 €. It comes from a recorded donor car, and 5 units are available. The listing shows every side of the engine and the fitted parts.
Buying a used M52B25: checklist
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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 M52B25
What is the difference between the M52B25 and other M52 engines?
The M52B25 makes 125 kW (170 HP) and 245 Nm. The other M52 engines are: M52B28 with 142 kW (193 HP) and 280 Nm (1995 to 2000).
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 M52 Engines · Search M52B25 in the shop
What should I replace when I fit a used M52B25 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 M52 Engines · Search M52B25 in the shop
How much is a replacement M52B25 engine for a BMW E39 523i?
A used M52B25 for the BMW E39 523i 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 M52B25 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 M52 Engines · Search M52B25 in the shop
What is the BMW M52B25 engine?
The BMW M52B25 is a 2.5 liter (2,494 cc) petrol engine from the M52 family. It has an inline 6, DOHC, 24 valve layout with no turbo (naturally aspirated), and makes 125 kW (170 HP) with 245 Nm of torque. BMW built it from 1995 to 2000 and it meets the Euro 2 emission standard.
You find the M52B25 in the BMW E36 323i, BMW E39 523i and BMW E46 323i. What we list: BMW M52 petrol engines for E36, E39, E46 and Z3.
At Autowerke Engines every M52B25 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 M52 Engines · Search M52B25 in the shop
How do I know a used M52B25 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. If you want more photos or a short video of a unit, ask the desk and we send them before you pay.
On a petrol engine like the M52B25, 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 M52 Engines · Search M52B25 in the shop
How much does a used BMW M52B25 engine cost?
A used BMW M52B25 engine in our yard usually costs between 1.250 € and 2.100 €. 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 M52 Engines · Search M52B25 in the shop
How much is a replacement M52B25 engine for a BMW E36 323i?
A used M52B25 for the BMW E36 323i 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 M52B25 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 M52 Engines · Search M52B25 in the shop
How long does delivery of an M52B25 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 M52 Engines · Search M52B25 in the shop
Will the M52B25 engine fit my BMW E39 523i?
Yes, if your BMW E39 523i was built with the M52B25. BMW used this 2.5 liter (2,494 cc) petrol engine with 125 kW (170 HP) in the E39 523i from about 1995 to 2000.
In our records the M52B25 is the engine for the E39 523i, which makes the match simple. Still, check the code on your old engine or send us your VIN.
Also tell us if your E39 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 M52 Engines · Search M52B25 in the shop
How much power and torque does the BMW M52B25 have?
From the factory the BMW M52B25 makes 125 kW (170 HP) and 245 Nm of torque. It is a 2.5 liter (2,494 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 M52B25 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 M52 Engines · Search M52B25 in the shop
How much is a replacement M52B25 engine for a BMW E46 323i?
A used M52B25 for the BMW E46 323i 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 M52B25 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 M52 Engines · Search M52B25 in the shop
Is the BMW M52B25 a diesel or petrol engine?
The M52B25 is a petrol engine. It is a 2.5 liter (2,494 cc) inline 6, DOHC, 24 valve unit with no turbo (naturally aspirated), and it was built to the Euro 2 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 M52 Engines · Search M52B25 in the shop
Does a used M52B25 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 M52 Engines · Search M52B25 in the shop
Will the M52B25 engine fit my BMW E46 323i?
Yes, if your BMW E46 323i was built with the M52B25. BMW used this 2.5 liter (2,494 cc) petrol engine with 125 kW (170 HP) in the E46 323i from about 1995 to 2000.
In our records the M52B25 is the engine for the E46 323i, which makes the match simple. Still, check the code on your old engine or send us your VIN.
Also tell us if your E46 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 M52 Engines · Search M52B25 in the shop
Will the M52B25 engine fit my BMW E36 323i?
Yes, if your BMW E36 323i was built with the M52B25. BMW used this 2.5 liter (2,494 cc) petrol engine with 125 kW (170 HP) in the E36 323i from about 1995 to 2000.
In our records the M52B25 is the engine for the E36 323i, 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 M52 Engines · Search M52B25 in the shop
What comes with a used M52B25 engine?
Each M52B25 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 M52 Engines · Search M52B25 in the shop
Which cars use the BMW M52B25 engine?
BMW fitted the M52B25 to the BMW E36 323i, BMW E39 523i and BMW E46 323i. These cars were built with this engine from about 1995 to 2000.
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 M52 family are the M52B28 (193 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 M52 Engines · Search M52B25 in the shop
Can you check if an M52B25 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 M52B25, 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 323i, BMW E39 523i and BMW E46 323i.
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 M52 Engines · Search M52B25 in the shop
Delivery, warranty and payment
Every M52B25 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.
A 12-month warranty covers eligible internal failure when the engine is fitted by a qualified workshop with new fluids and filters. You can pay by card, bank transfer or crypto and receive the invoice by email straight away.
