BMW 3 Series 340i Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK BMW 3 Series 340i engine specialists. Compare prices on reconditioned, rebuilt and used B58 engines for the F30 and G20 340i - the 3.0-litre turbocharged straight-six that set a new benchmark for performance and refinement.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £4,000 to £6,500
Used from £2,500 · Reconditioned from £3,800 · Common codes: B58B30M0, B58B30M1, B58B30O1
From £2,500
Tested, bare/short engine
From £3,800
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
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3 Simple Steps3 Simple Stepsto Finding the Best BMW 3 Series 340i Replacement Engineto Finding the Best BMW 3 Series 340i Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryBMW 3 Series 340i - Engine History & Specs at a Glance
The BMW 340i arrived in 2015 as the flagship petrol model of the F30 3 Series, replacing the 335i and introducing the all-new B58 engine. The B58 - a 3.0-litre turbocharged straight-six - represented a significant leap forward from the N55, with a closed-deck aluminium block, a single twin-scroll turbocharger, and air-to-liquid intercooling. It has since won multiple Ward's 10 Best Engines awards and is widely regarded as one of BMW's finest modern powerplants.
Variant HistoryBMW 3 Series 340i - Engine History & Specs at a Glance
The BMW 340i arrived in 2015 as the flagship petrol model of the F30 3 Series, replacing the 335i and introducing the all-new B58 engine. The B58 - a 3.0-litre turbocharged straight-six - represented a significant leap forward from the N55, with a closed-deck aluminium block, a single twin-scroll turbocharger, and air-to-liquid intercooling. It has since won multiple Ward's 10 Best Engines awards and is widely regarded as one of BMW's finest modern powerplants.
BMW 3 Series 340i
Fuel TypePetrol
Engine Size3.0L (2,998 cc)
Power Output Range320-386 hp across the variant's historyEngine History Timeline
B58B30M0 3.0-litre straight-six turbo (326 bhp / 240 kW) - F30 generation launched, replaced the N55-powered 335i
B58B30O1 3.0-litre straight-six turbo (374 bhp / 275 kW) - Higher-output version for later applications
B58B30O1 3.0-litre straight-six turbo (382 bhp) - G20 M340i generation, updated with mild-hybrid technology
B58B30M2 3.0-litre straight-six turbo (386 bhp) - LCI update, increased power and torque
Key Specs Snapshot
Fuel TypePetrolEngine Size3.0L (2,998 cc)Power Output Range320-386 hp across the variant's historyYears Produced2015-presentEngine ArchitectureClosed-deck aluminium block, DOHC, Valvetronic, Double VANOSTurbochargerSingle twin-scroll with air-to-liquid intercoolerEvery engine fitted to the BMW 3 Series 340i is covered below, with UK rebuilt pricing and known failure points.
BMW 3 Series 340i Engine Codes - Specifications & Replacement CostBMW 3 Series 340i Engine Codes - Specifications & Replacement Cost
3.0L Petrol (2015-2018)
Power Output326 bhp / 240 kW at 5,500 rpmTorque450 NmYears Fitted2015-2018
Compatible Trim Levels
- 340i
- 340i SE
- 340i Sport
- 340i M Sport
- 340i xDrive
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£2,500-£4,000
Reconditioned
Addressed known issues, tested
£3,800-£5,500
Rebuilt
Full teardown, upgraded internals
£4,500-£6,500
Common Failure
Coolant leaks from the water-to-air intercooler seals and oil filter housing gasket leaks are the most frequently reported issues on early B58 engines.
The BMW 3 Series 340i's B58 engine is widely regarded as one of BMW's most reliable modern powerplants - but it's not immune to age-related issues. Coolant leaks, oil filter housing gasket failures, and valve cover gasket deterioration are the most common concerns. Rebuilt engines through EnginesMarket include upgraded components addressing the original failure points, plus a minimum 12-month unlimited-mileage warranty.
Why the BMW 3 Series 340i B58 Engine Loses Coolant
Affected Vehicles
BMW 3 Series 340i (B58B30, 2015-present)
Typical Failure Mileage
40,000-80,000 miles
Root Cause
The B58's water-to-air intercooler uses seals that can degrade over time, leading to coolant leaks. The water pump and thermostat housing are also known failure points.
Why It Happens
The B58's water-to-air intercooler uses seals that can degrade over time, leading to coolant leaks. The water pump and thermostat housing are also known failure points.
Dealer (parts + labour)
£800-£1,500
Specialist (parts + labour)
£400-£800
What it involves
Replace intercooler seals, pressure test system
Suitability
If caught early with no overheating
1 - 2 daysDealer (parts + labour)
£1,000-£1,800
Specialist (parts + labour)
£500-£1,000
What it involves
Replace water pump and thermostat housing
Suitability
Preventative maintenance at 60k miles
1 - 2 daysDealer (parts + labour)
£8,000-£12,000
Specialist (parts + labour)
£4,500-£7,500 (matches Section 4 rebuilt pricing)
What it involves
Supply & fit, fully rebuilt B58 unit, 12-month warranty
Suitability
If engine has overheated and sustained damage
1 - 2 daysAll prices are indicative UK market ranges based on current UK specialist supplier data.| Repair Tier | Dealer (Parts + Labour) | Specialist (Parts + Labour) | What It Involves | Suitability | Estimated Time |
|---|---|---|---|---|---|
 Coolant leak repair - intercooler seals Minor | £800-£1,500 | £400-£800 | Replace intercooler seals, pressure test system | If caught early with no overheating | 1 - 2 days |
 Coolant leak repair - water pump/thermostat Best Value | £1,000-£1,800 | £500-£1,000 | Replace water pump and thermostat housing | Preventative maintenance at 60k miles | 1 - 2 days |
Full Replacement - rebuilt/reconditioned engine Best Value | £8,000-£12,000 | £4,500-£7,500 (matches Section 4 rebuilt pricing) | Supply & fit, fully rebuilt B58 unit, 12-month warranty | If engine has overheated and sustained damage | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A BMW 3 Series 340i F30 (2015-2018) is typically worth £8,000-£18,000, while a G20 M340i (2019+) commands £20,000-£45,000 depending on mileage and condition [THIRD-PARTY]. For F30 examples under £10,000, a used engine or targeted repair may be more appropriate. For G20 cars, a rebuilt engine with warranty is a straightforward decision given the vehicle's value.
Our Recommendation
Our Recommendation
For B58 340i owners, preventative cooling system maintenance is the smart play. Replacing the water pump and thermostat housing at 60,000 miles costs far less than an engine replacement if a leak leads to overheating. Regularly check coolant levels and inspect for visible puddles under the vehicle.
Don't Let Engine Failure Write Off Your BMW 3 Series 340i
The BMW 340i's B58 engine is one of the finest straight-sixes ever built - but even the best engines need maintenance. Every rebuilt BMW 3 Series 340i 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 rebuilt B58 BMW 3 Series 340i engine prices
12-Month Minimum
UK Specialists Vetted
Best Price GuidanceImportant Information
Important Information
"All prices are indicative UK market ranges based on historical quote data and repair requests from our network of engine specialists. Dealer pricing is estimated based on published main dealer labour rates and genuine OEM parts pricing. Specialist pricing reflects actual quote data from EnginesMarket's UK network. Actual costs vary depending on damage severity, vehicle condition, variant, and workshop location within the UK. Use our free comparison tool to get tailored quotes for your specific BMW 3 Series 340i. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier."
BMW 3 Series 340i Engine ReplacementFrequently Asked Questions
Question 1How much does a BMW 3 Series 340i engine replacement cost in the UK-
A BMW 3 Series 340i engine replacement typically costs between £2,500 and £7,500 supply-only, depending on the condition type and variant.
- Used engines: £2,500-£4,500
- Reconditioned engines: £3,800-£6,000
- Rebuilt engines: £4,500-£7,500 with 12-month warranty
Question 2What is the difference between the BMW 340i and M340i-
The 340i (F30, 2015-2018) uses the B58B30M0 engine producing 326 bhp and is the standard performance petrol model. The M340i (G20, 2019-present) uses the higher-output B58B30O1 engine producing 374-382 bhp, with revised suspension, brakes, and an M Sport differential as standard. Both share the same B58 engine family, but the M340i represents a significant step up in performance and chassis tuning.
-> Compare BMW 3 Series 340i vs M340i engine pricesQuestion 3Is the B58 engine reliable in the BMW 340i-
Yes, the B58 is widely regarded as one of BMW's most reliable modern engines. It has won multiple Ward's 10 Best Engines awards and is praised for its robust closed-deck aluminium block design. However, like any engine, it has known issues - coolant leaks, oil filter housing gasket leaks, and PCV valve failures are the most common. Regular maintenance and early intervention prevent these from becoming major problems.
-> Compare BMW 3 Series 340i replacement engine pricesQuestion 4What are the signs of a failing PCV valve in a BMW 340i-
The most common signs of PCV valve failure in the B58 engine are:
- Rough idle or engine misfires
- Oil in the intake or charge pipe
- Check engine light with lean condition codes
Question 5How long does a BMW 3 Series 340i engine replacement take-
A typical BMW 3 Series 340i engine replacement takes 2-4 working days:
- F30 (2015-2018): 10-14 hours labour - around 2-3 days
- G20 M340i (2019-present): 10-14 hours labour - around 2-3 days
Question 6Does a rebuilt BMW 3 Series 340i engine come with a warranty-
Yes. Every rebuilt BMW 3 Series 340i 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
- Always confirm exact warranty terms with your chosen supplier
Why Choose UsCompare BMW 3 Series 340iEngine PricesToday
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12-Month Warranty on every rebuilt BMW 340i engine
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Comparing quotes for your BMW 3 Series 340i is free, quick, and completely no-obligation. Whether you need a used B58B30M0 for an F30, a reconditioned B58 for a cost-effective rebuild, or a fully rebuilt B58B30O1 for a G20 M340i, our network of UK specialists has the right engine for your exact 340i and engine code. Enter your registration above and start comparing today.
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