The BMW 318i in the second 3 Series generation (E30, built 1982–1994) was built with one engine, the M40B18: a 1.8 L petrol inline-4 with 113 hp.
Below you will find how to identify the engine in your 318i, the faults to look for, current prices for a replacement and the swap options that make sense.
- Generation: second 3 Series, 1982–1994
- Body styles: E30 (saloon, Touring, coupé, convertible)
- Engines: M40B18
- Output: 113 hp
- Replacement engines in stock: ask the desk for the next arrival
Which engine is in your 318i?
| Engine code | Built | Power | Torque | Type |
|---|---|---|---|---|
| M40B18 | 1987–1994 | 113 hp | 162 Nm | 1.8 L petrol inline-4, naturally aspirated |
M40B18 in the 318i
The M40B18 was used in the E30 318i, built 1987–1994. It is a 1.8 L naturally aspirated petrol inline-4 with 113 hp and 162 Nm.
Reading the code: M marks an M-series code, the naming BMW used for its engine families up to the early 2000s; 40 is the family number; B stands for petrol (from the German Benzin); 18 is the capacity in decilitres, so 1.8 litres.
318i engines by model year
| Model year | Engine |
|---|---|
| 1987 | M40B18 (113 hp) |
| 1988 | M40B18 (113 hp) |
| 1989 | M40B18 (113 hp) |
| 1990 | M40B18 (113 hp) |
| 1991 | M40B18 (113 hp) |
| 1992 | M40B18 (113 hp) |
| 1993 | M40B18 (113 hp) |
| 1994 | M40B18 (113 hp) |
The 318i kept the same engine for the whole E30 run, which makes ordering simple: any unit with the same code fits, subject to the gearbox, drive type and sump.
Other cars with the same engine as the 318i
A replacement engine does not have to come from another 318i. 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.
M40B18: BMW E36 318i, BMW E34 518i.
How to confirm your engine code
The 318i only used the M40B18, but the exact version can still change with the build date, gearbox and market. 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 318i engine problems
The M40B18 in the 318i shares the known weak points of the M40 family. Full M40 guide.
| Known fault | What to check |
|---|---|
| Timing belt | Look for a dated belt sticker or invoice. |
| Camshaft lobe wear | Remove the cam cover and inspect the lobes. |
| Rocker arms | Listen at idle with the oil hot. |
| Cooling and thermostat | Check the hoses for swelling and the radiator tanks for cracks. |
Timing belt. The M40 belt has a short life compared with later engines. If it breaks, valves meet pistons. Change it with the tensioner every 40,000 to 60,000 km.
Camshaft lobe wear. M40 cams are known for wearing their lobes, particularly where oil changes were stretched. The engine loses power and becomes noisy.
Rocker arms. Rocker arms wear with the cam; a ticking valve train is the clue.
Cooling and thermostat. Plastic and rubber cooling parts are now thirty years old and should be renewed as a set.
Symptoms to watch for on the 318i
Engine stops suddenly and will not restart. On belt-driven engines, a snapped timing belt. Do not keep cranking: on an interference engine the valves are probably already bent.
Looking after the 318i engine
- Oil: 10W-40 semi-synthetic, about 4.0 litres with filter.
- Service interval: Oil every 7,500 km; timing belt every 40,000 to 60,000 km or four years.
- Timing drive: Rubber timing belt with tensioner, changed on time.
- Workshop notes: Because cam wear is common, a new camshaft and rockers are a sensible addition when a used M40 is fitted.
Buying a used engine for the 318i: checklist
- 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.
- 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.
- 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.
- 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.
- Timing belt history. A timing belt must be changed on time and distance. With no dated record, treat the belt, tensioner and water pump as due and replace them before the first start.
- 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.
BMW 318i replacement engine cost
We do not have a 318i engine 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.
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.
Will it fit my 318i?
Engine swaps and upgrades for the 318i
These engines were fitted to other versions of the E30 at the factory, which makes them the most practical upgrades: the body was designed around them and many parts are shared.
| Engine | Factory model | Power | Gain |
|---|---|---|---|
| M21D24 | E30 324td | 115 hp | +2 hp |
| M20B27 | E30 325e | 125 hp | +12 hp |
| M20B20 | E30 320i | 129 hp | +16 hp |
| M20B23 | E30 323i | 139 hp | +26 hp |
| M42B18 | E30 318is | 140 hp | +27 hp |
Can I fit the M21D24 in my 318i?
It is a full conversion: the M21D24 runs on diesel and the M40B18 on petrol, so the fuel system, wiring, engine control unit, instrument coding and usually the gearbox change too. The gain is 2 hp and 58 Nm. In Germany and most of Europe an engine swap must be inspected and registered.
Can I fit the M20B27 in my 318i?
It is a conversion rather than a replacement: the M20B27 is an inline-6 and your M40B18 an inline-4, so mounts, sump, cooling, exhaust, wiring and the engine control unit all change. The gain is 12 hp and 78 Nm. In Germany and most of Europe an engine swap must be inspected and registered.
Can I fit the M20B20 in my 318i?
It is a conversion rather than a replacement: the M20B20 is an inline-6 and your M40B18 an inline-4, so mounts, sump, cooling, exhaust, wiring and the engine control unit all change. The gain is 16 hp and 2 Nm. In Germany and most of Europe an engine swap must be inspected and registered.
Fitting a replacement engine in the 318i
- Fit a new timing belt kit. Fit a new belt, tensioner and water pump and set the timing with the correct tools before the first start.
- 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.
- 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.
- 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.
- 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.
318i engine questions
Will the M40B18 engine fit my BMW E36 318i?
Yes, if your BMW E36 318i was built with the M40B18. BMW used this 1.8 liter (1,796 cc) petrol engine with 83 kW (113 HP) in the E36 318i from about 1987 to 1994.
Some E36 318i cars were built with a different engine: the M42B18 and M43B18. These look alike from the outside, so check the code on your 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 M40 Engines · Search M40B18 in the shop
How much is a replacement M40B18 engine for a BMW E36 318i?
A used M40B18 for the BMW E36 318i costs from about 700 € to 1.350 € 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 M40B18 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 M40 Engines · Search M40B18 in the shop
How much is a replacement M40B18 engine for a BMW E30 318i?
A used M40B18 for the BMW E30 318i costs from about 700 € to 1.350 € 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 M40B18 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 M40 Engines · Search M40B18 in the shop
How much is a replacement M40B18 engine for a BMW E36 318i?
A used M40B18 for the BMW E36 318i costs from about 700 € to 1.350 € 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 M40B18 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 M40 Engines · Search M40B18 in the shop
Does a used M40B18 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 M40 Engines · Search M40B18 in the shop
How much power and torque does the BMW M40B18 have?
From the factory the BMW M40B18 makes 83 kW (113 HP) and 162 Nm of torque. It is a 1.8 liter (1,796 cc) inline 4, SOHC, 8 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 M40B18 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 M40 Engines · Search M40B18 in the shop
What is the BMW M40B18 engine?
The BMW M40B18 is a 1.8 liter (1,796 cc) petrol engine from the M40 family. It has an inline 4, SOHC, 8 valve layout with no turbo (naturally aspirated), and makes 83 kW (113 HP) with 162 Nm of torque. BMW built it from 1987 to 1994 and it meets the Euro 1 emission standard.
You find the M40B18 in the BMW E30 318i and BMW E36 318i. What we list: BMW M40 1.6 and 1.8 petrol engines for E30 and E36.
At Autowerke Engines every M40B18 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 M40 Engines · Search M40B18 in the shop
How much is a replacement M40B18 engine for a BMW E30 318i?
A used M40B18 for the BMW E30 318i costs from about 700 € to 1.350 € 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 M40B18 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 M40 Engines · Search M40B18 in the shop
How do I know a used M40B18 engine is in good shape?
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. 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 M40B18, 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 M40 Engines · Search M40B18 in the shop
Will the M40B18 engine fit my BMW E36 318i?
Yes, if your BMW E36 318i was built with the M40B18. BMW used this 1.8 liter (1,796 cc) petrol engine with 83 kW (113 HP) in the E36 318i from about 1987 to 1994.
Some E36 318i cars were built with a different engine: the M42B18 and M43B18. These look alike from the outside, so check the code on your 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 M40 Engines · Search M40B18 in the shop
Delivery, warranty and payment
Before a 318i 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.
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.
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