How much does a BMW 3 Series 320i engine replacement cost in the UK-

A BMW 3 Series 320i engine replacement typically costs between £1,800 and £6,000 supply-only, depending on the engine code and condition type. Used engines: £400-£1,500 (older codes) to £1,500-£2,800 (B48). Reconditioned engines: £1,000-£4,500. Rebuilt engines: £1,800-£6,000 with 12-month warranty. Supply and fit adds approximately £650-£1,000 in labour depending on the generation.

What are the signs of timing chain failure in a BMW 3 Series 320i-

On N43 and N20 320i engines, the key warning signs are: a rattling or clacking noise from the front of the engine on cold start, a whining noise that increases with engine RPM, rough idle or misfires, and engine management light with timing-related fault codes. If you hear any of these, get the car inspected immediately - catching it early can save your engine.

Is it worth replacing the engine in a BMW 3 Series 320i-

It depends on the age and value of your car. E46 320i (worth £1,500-£5,000): repair if possible; full rebuild only if the car is exceptional. E90 320i (worth £2,500-£8,000): timing chain repair or used engine often makes sense. F30 320i (worth £5,000-£14,000): rebuilt engine with warranty is usually a sound investment. G20 320i (worth £15,000+): replacement cost is small relative to vehicle value. Always compare the cost of replacement against your car's current market value before deciding.

What's the difference between the BMW 320i and 330i engines-

The 320i and 330i share the same B48 engine family but with different tuning. 320i (B48B20A): 181-184hp. 330i (B48B20B): 248hp. The 330i uses a higher-output version of the same modular 2.0-litre turbo engine, with different pistons, turbocharger, and engine management calibration. Both are four-cylinder, 2.0-litre units - the 320i is the more fuel-efficient choice, while the 330i offers significantly more performance.

How long does a BMW 3 Series 320i engine replacement take-

A typical BMW 3 Series 320i engine replacement takes 2-5 working days. E46/E90 (M54/N46/N43): 10-14 hours labour - around 2-3 days. F30/G20 (N20/B48): 8-12 hours labour - around 2-3 days. Supply-only engines can be delivered nationwide within 1-2 working days. Full supply & fit typically adds 1-2 days for booking and workshop scheduling.

Does a rebuilt BMW 3 Series 320i engine come with a warranty-

Yes. Every rebuilt BMW 3 Series 320i engine supplied through EnginesMarket comes with a minimum 12-month unlimited-mileage warranty as standard. The warranty covers manufacturing defects and parts failure. Upgraded components address the original failure points (e.g. improved timing chain tensioners on N43/N20). Always confirm exact warranty terms with your chosen supplier.

BMW 320i SPECIALISTS

BMW 3 Series 320i Engine Replacement Compare Prices & Get Quotes

Get quotes today from trusted UK BMW 3 Series 320i engine specialists. Compare prices on reconditioned, rebuilt and used engines for every 320i generation - from the E46 M54 to the G20 B48.

Supply & Fit Available

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BMW 3 Series 320i Engine

from£3,800 to £6,000

Usedfrom £1,500
Reconditionedfrom £2,800
Common codesM54B22, N46B20, N43B20A

BMW 3-seriesUsed Engine — M54B22

BMW 3-series 320i Reconditioned Engine — M54B22

BMW 3-seriesReconditioned Engine — M54B22

BMW 3-series 320i Rebuilt Engine — M54B22

BMW 3-seriesRebuilt Engine — M54B22

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How it works

3 Simple Steps to Finding the Right Replacement Engine

Clear information first, then the right engine and specialist for your exact vehicle.

Variant History

BMW 3 Series 320i Engine History & Specs at a Glance

The BMW 320i has been the heart of the 3 Series petrol range since the E21 generation launched in 1975. Over five decades, the 320i badge has moved from a carburettor-fed four-cylinder to a six-cylinder M54, then back to four-cylinder N-series engines, and finally to the modern modular B48 turbo - each generation bringing more power, efficiency and complexity.

1975
M10B20, 2.0-litre four-cylinder, fuel-injected (123hp) - E21 generation
1977
M20B20, 2.0-litre six-cylinder (120hp) - E21 generation, carburettor
1982
M20B20, 2.0-litre six-cylinder (125hp) - E30 generation
1991
M50B20, 2.0-litre straight-six (150hp) - E36 generation, DOHC
1998
M52TUB20, 2.0-litre straight-six (150hp) - E46 generation, double VANOS
2000
M54B22, 2.2-litre straight-six (170hp) - E46 facelift, increased displacement
2005
N46B20, 2.0-litre four-cylinder (150hp) - E90 generation, Valvetronic
2007
N43B20A, 2.0-litre four-cylinder (170hp) - E90/E92 generation, direct injection
2012
N20B20A/B, 2.0-litre four-cylinder turbo (184hp) - F30 generation, TwinPower Turbo
2015
B48B20A, 2.0-litre four-cylinder turbo (181hp) - F30 LCI / G20 generation, modular engine
2019
B48B20B, 2.0-litre four-cylinder turbo (184hp) - G20 generation, updated

Every engine fitted to the BMW 3 Series 320i is covered below, with UK rebuilt pricing and known failure points.

Engine Codes & Pricing

BMW 3 Series 320i Engine Codes Specifications & Replacement Cost

Find your exact engine code, specs and UK replacement cost guide.

M54B22 — 2.2L Petrol (2000-2005)

Power Output: 170hp
Years Fitted: 2000-2005

Can’t find your exact engine code?-> Get quotes for M54B22 BMW 3 Series 320i engine replacement

-> Get quotes for M54B22 BMW 3 Series 320i engine replacement

Common Problems

BMW 3 Series 320i Engine Problems Repair Cost vs Replacement

The BMW 3 Series 320i's petrol engines have evolved significantly over the years, but several recurring failure points drive replacement demand. The N43 and N20 timing chain issues are the most common reasons 320i owners seek engine replacement, while the B48's cooling system problems typically require less drastic intervention. Rebuilt engines through EnginesMarket include upgraded components addressing the original failure point, plus a minimum 12-month unlimited-mileage warranty.

Common failure points and repair options

Timing Chain Failure

Affected: BMW 3 Series 320i (N43B20A, 2007-2012; N20B20A/B, 2012-2015)
Typical failure mileage: 30,000-90,000 miles

Root cause

The timing chain tensioner was underspecified, allowing the chain to slacken and rub against - or break - the plastic guides. On interference engines, a skipped tooth means valve-to-piston contact and catastrophic failure.

Repair options

Repair tier	Dealer price	Specialist price
Timing chain replacement (preventative)	£1,500-£2,500	£800-£1,500
Full Replacement - rebuilt/reconditioned engine	£5,000-£8,000	£2,500-£4,500 (matches Section 4 rebuilt pricing)

Our recommendation

If you hear a rattling noise from the front of the engine on cold start, get it inspected immediately. Replacing the timing chain and tensioner before failure costs £800-£1,500 at a specialist and can save your engine. If the engine has already jumped timing, a full replacement is usually the most cost-effective route - a specialist rebuild with upgraded components costs less than a dealer replacement and carries a 12-month warranty.

-> Compare rebuilt N43/N20 BMW 3 Series 320i engine prices

Coolant System Failure

Affected: BMW 3 Series 320i (B48B20A/B, 2015-present)
Typical failure mileage: 40,000-80,000 miles

Root cause

The B48's cooling system uses plastic components - water pump, thermostat housing, oil filter housing, and coolant pipes - that become brittle with heat cycling. Seals fail, pipes crack, and coolant leaks develop.

Repair options

Repair tier	Dealer price	Specialist price
Coolant leak repair (component replacement)	£600-£1,200	£300-£800
Full Replacement - rebuilt engine	£5,000-£8,000	£3,800-£6,000 (matches Section 4 rebuilt pricing)

Our recommendation

For B48 320i owners, preventative cooling system maintenance is the smart play. Replacing the water pump and thermostat housing at 60,000 miles as a preventative measure costs far less than an engine replacement if a leak leads to overheating. If the engine has already overheated, a specialist rebuild with renewed cooling components is the reliable long-term solution.

-> Compare rebuilt B48 BMW 3 Series 320i engine prices

Oil Consumption

Affected: BMW 3 Series 320i (N46B20, 2005-2007)
Typical failure mileage: 50,000-100,000 miles

Root cause

Valve stem seals harden and lose their sealing ability, allowing oil to seep past the valves into the combustion chamber.Piston ring wear can also contribute.

Repair options

Repair tier	Dealer price	Specialist price
Valve stem seal replacement	£1,200-£2,000	£600-£1,200
Full Replacement - rebuilt engine	£4,000-£6,000	£1,800-£2,800 (matches Section 4 rebuilt pricing)

Our recommendation

For N46 320i owners, monitor oil consumption carefully. If you're adding more than 1 litre per 1,000 miles, valve stem seal replacement is the cost-effective fix. A full rebuilt engine is only justified if the car is otherwise in excellent condition and you plan to keep it.

-> Compare rebuilt N46 BMW 3 Series 320i engine prices

Don't Let Engine Failure Write Off Your BMW 3 Series 320i

Whether you own an E46 M54, an E90 N43, an F30 N20, or a G20 B48, engine failure doesn't have to mean the end of the road. Every rebuilt BMW 3 Series 320i engine through EnginesMarket comes with upgraded components addressing the original failure points, a minimum 12-month unlimited-mileage warranty, and nationwide delivery. Compare specialist prices today - and save thousands over main dealer rates.

Compare BMW 3 Series 320i Engine Replacement Prices Now ->

FAQ

BMW 3 Series 320i Engine ReplacementFrequently Asked Questions

Everything BMW 3 Series 320i owners usually ask before choosing a rebuilt, reconditioned or used replacement engine.

It depends on the age and value of your car:

E46 320i (worth £1,500-£5,000): repair if possible; full rebuild only if the car is exceptional
E90 320i (worth £2,500-£8,000): timing chain repair or used engine often makes sense
F30 320i (worth £5,000-£14,000): rebuilt engine with warranty is usually a sound investment
G20 320i (worth £15,000+): replacement cost is small relative to vehicle value

-> Get a BMW 3 Series 320i replacement cost assessment

Yes. Every rebuilt BMW 3 Series 320i engine supplied through EnginesMarket comes with a minimum 12-month unlimited-mileage warranty as standard.

The warranty covers manufacturing defects and parts failure
Upgraded components address the original failure points (e.g. improved timing chain tensioners on N43/N20)
Always confirm exact warranty terms with your chosen supplier

-> Get a warranted BMW 3 Series 320i engine quote

Why Choose Us

Compare BMW 3 Series 320i Engine Prices Today

Comparing quotes for your BMW 3 Series 320i is free, quick, and completely no-obligation. Whether you need a used M54B22 for an E46, a reconditioned N43B20A for an E90, or a rebuilt B48B20A for a G20, our network of UK specialists has the right engine for your exact 320i and engine code. Enter your registration above and start comparing today.

500+500+ BMW 3 Series 320i engines supplied through our network

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BMW 3 Series 320i Engine Replacement Compare Prices & Get Quotes

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3 Simple Steps to Finding the Right Replacement Engine

BMW 3 Series 320i Engine History & Specs at a Glance

BMW 3 Series 320i Engine Codes Specifications & Replacement Cost

M54B22 — 2.2L Petrol (2000-2005)

BMW 3 Series 320i Engine Problems Repair Cost vs Replacement

Timing Chain Failure

Coolant System Failure

Oil Consumption

Don't Let Engine Failure Write Off Your BMW 3 Series 320i

BMW 3 Series 320i Engine ReplacementFrequently Asked Questions

Compare BMW 3 Series 320i Engine Prices Today