BMW built the N46B18 from 2004 to 2007. It is a 1.8 L naturally aspirated petrol inline-4 with 115 hp and 175 Nm, part of the N46 family. You will find it in the BMW E87 316i and BMW E90 316i.
This guide is about the N46B18 specifically: its specification, the cars that use it, how it differs from the other N46 versions, what to check, prices from our stock and fitment answers for each model. For the history of the whole family, read our N42 and N46 guide.
- Capacity and layout: 1.8 L, inline-4, naturally aspirated
- Output: 115 hp and 175 Nm
- Production: 2004–2007
- Fitted to: 2 models across 2 chassis generations
- In our stock: ask the desk for the next arrival
N46B18 specifications
| Item | Value |
|---|---|
| Engine code | N46B18 |
| Family | N46 |
| Capacity | 1.8 L |
| Layout | Inline-4 |
| Fuel | Petrol |
| Aspiration | Naturally aspirated |
| Power | 115 hp |
| Torque | 175 Nm |
| Specific output | 64 hp per litre |
| Production | 2004–2007 |
| Models | 2 |
Built from 2004 to 2007, the N46B18 displaces 1.8 L in an inline-4 layout and is naturally aspirated. It produces 115 hp and 175 Nm on petrol. That is about 64 hp and 97 Nm per litre, a relaxed tune aimed at torque, durability and economy. Within the N46 family, the N46B20 (150 hp) is more powerful. It was fitted to the BMW E87 316i and BMW E90 316i.
What the code N46B18 means
- N marks an N-series code, the generation of BMW engines introduced from 2001.
- 46 is the family number.
- B stands for petrol (from the German Benzin).
- 18 is the capacity in decilitres, so 1.8 litres.
Which BMW models use the N46B18
| Model | Generation | Built |
|---|---|---|
| BMW E87 316i | first 1 Series five-door | 2004–2011 |
| BMW E90 316i | fifth 3 Series saloon | 2005–2012 |
In the E87 first 1 Series five-door (2004–2011), the N46B18 powered the 316i. Engines from other models fit the E87 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E87 engines
In the E90 fifth 3 Series saloon (2005–2012), the N46B18 powered the 316i. Engines from other models fit the E90 as long as the sump, mounts and ancillaries match, which we check against your VIN. All E90 engines
N46B18 compared with other N46 versions
| Code | Capacity | Power | Torque | Years |
|---|---|---|---|---|
| N46B18 | 1.8 L | 115 hp | 175 Nm | 2004–2007 |
| N46B20 | 2.0 L | 150 hp | 200 Nm | 2004–2012 |
N46B18 or N46B20?
The N46B20 has 35 hp more than the N46B18 (150 against 115 hp), from 2.0 L instead of 1.8 L, and was built 2004–2012. 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 N46B18 problems
The N46B18 shares its weak points with the rest of the N46 family. These are the faults to check on a used unit and on your own engine. The full explanation of each is in the N42 and N46 guide.
| Known fault | What to check |
|---|---|
| Oil consumption | Ask for consumption figures and check the spark plugs for oil fouling. |
| Timing chain stretch | Listen for a rattle on a cold start and check the camshaft timing values. |
| Valvetronic motor and eccentric shaft sensor | Check for Valvetronic fault codes. |
| Vacuum pump and oil leaks | Look at the back of the head. |
| Crankcase ventilation | Check for a whistle at idle. |
Vacuum pump and oil leaks. The vacuum pump seal and the valve cover gasket leak oil.
N46B18 maintenance
- 5W-30 BMW Longlife-01 or Longlife-04, about 4.25 litres.
- Oil every 15,000 km; shorten to 10,000 km to protect the chain.
- Timing chain at the front with balance shafts.
Will the N46B18 fit my car?
Will the N46B18 fit my BMW E87 316i?
For the BMW E87 316i, the N46B18 is the factory engine and the one to order. The first 1 Series five-door was built 2004–2011, and the N46B18 was produced 2004–2007, 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 E87 316i?
We do not have an N46B18 on the shelf for the E87 316i 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 N46B18 fit my BMW E90 316i?
For the BMW E90 316i, the N46B18 is the factory engine and the one to order. The fifth 3 Series saloon was built 2005–2012, and the N46B18 was produced 2004–2007, 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 E90 316i?
We do not have an N46B18 on the shelf for the E90 316i 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.
N46B18 prices
We do not have an N46B18 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 N46B18: checklist
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Double VANOS units and solenoids. Ask for the adaptation values or fault history if the engine was running. Solenoids are inexpensive and are often replaced as a matter of course on a used engine.
- Valvetronic motor and eccentric shaft sensor. The Valvetronic motor and its sensor cause limp-mode faults when they fail. Inspect the connector and the seal around the motor for oil.
Questions about the N46B18
What should I check on a used BMW N46 engine?
Start with the basics: the engine code on the block, the recorded mileage and the photos. Make sure the code matches your car and the parts you need are on the unit.
On an N46 petrol engine, a fitter usually checks the spark plugs, the coils, the timing side and the oil seals. These parts are easy to check before fitting and easy to change if needed.
You can ask for extra photos, a close-up of the code stamp or a short video before you order. An inspection certificate can travel with the order on request.
Once fitted, change the oil and filter early and drive gently at first. Report any problem right away so the warranty stays valid.
See all N46 Engines · Inspection certificate
What should I know about the BMW N46 engine?
BMW N46 1.6 and 2.0 petrol engines for 316i and 320i. We list one version: N46B20 (2.0 liter (1,995 cc), 110 kW (150 HP), 2004 to 2012).
Because there is only one version, the code is easy to match. You still need the engine computer and wiring that suit your car.
The N46 family was used in chassis E90, E87, E60 and E46. 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.
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.
Which years were BMW N46 engines made?
BMW built the N46 engines we list from about 2004 to 2012. The N46B20 ran from 2004 to 2012.
They went into chassis E90, E87, E60 and E46. The exact year of a car matters, because BMW sometimes changed the engine version or its parts in the middle of a model's life.
Each listing in our yard names the engine year, so you can match it to the build date of 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.
Will the N46B20 engine fit my BMW E87 120i?
Yes, if your BMW E87 120i was built with the N46B20. BMW used this 2.0 liter (1,995 cc) petrol engine with 110 kW (150 HP) in the E87 120i from about 2004 to 2012.
In our records the N46B20 is the engine for the E87 120i, which makes the match simple. Still, check the code on your old engine or send us your VIN.
Also tell us if your E87 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 N46 Engines · Search N46B20 in the shop
How much is a replacement N46B20 engine for a BMW E46 318i?
A used N46B20 for the BMW E46 318i costs from about 1.000 € to 1.700 € 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 N46B20 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 N46 Engines · Search N46B20 in the shop
How long does delivery of an N46B20 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 N46 Engines · Search N46B20 in the shop
How much is a replacement N46B20 engine for a BMW E87 120i?
A used N46B20 for the BMW E87 120i costs from about 1.000 € to 1.700 € 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 N46B20 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 N46 Engines · Search N46B20 in the shop
Can you check if an N46B20 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 N46B20, we confirm that your car was built with this code or with a version that can take it. BMW used it in the BMW E90 320i, BMW E87 120i, BMW E60 520i and BMW E46 318i.
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 N46 Engines · Search N46B20 in the shop
How much is a replacement N46B20 engine for a BMW E60 520i?
A used N46B20 for the BMW E60 520i costs from about 1.000 € to 1.700 € 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 N46B20 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 N46 Engines · Search N46B20 in the shop
What comes with a used N46B20 engine?
Each N46B20 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 N46 Engines · Search N46B20 in the shop
Is the BMW N46B20 a diesel or petrol engine?
The N46B20 is a petrol engine. It is a 2.0 liter (1,995 cc) inline 4, DOHC, 16 valve unit with no turbo (naturally aspirated), and it was built to the Euro 4 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 N46 Engines · Search N46B20 in the shop
How much is a replacement N46B20 engine for a BMW E90 320i?
A used N46B20 for the BMW E90 320i costs from about 1.000 € to 1.700 € 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 N46B20 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 N46 Engines · Search N46B20 in the shop
Delivery, warranty and payment
Before an N46B18 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.
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.
N42 and N46 engine guide · All N42 and N46 engines · Send us your VIN
