BMW 3 Series M340d Engine ReplacementCompare Prices & Get Quotes

A replacement engine for a BMW M340d costs £2,500-£9,000 depending on condition and specification. Used B57D30B engines start from £2,500, reconditioned units range from £4,500-£7,000, and fully rebuilt engines with warranty cost £5,500-£8,500. Fitting adds £800-£1,500 due to the engine's complexity and 48V mild-hybrid system.

• Used engines are the cheapest but come with limited warranty
• Reconditioned engines are stripped and have worn parts replaced
• Rebuilt engines are fully machined and assembled to factory specification with a 12-month warranty

Common symptoms include DPF warning lights, reduced performance (limp mode), rough idling, increased fuel consumption, rattling from the engine bay (wastegate actuator), and coolant loss without visible leaks.

• DPF/EGR issues are the most common - often from short journeys
• Coolant loss points to a known pipe failure under the intake manifold
• Rattling at low speeds suggests wastegate actuator wear

A typical M340d is worth £30,000-£55,000 depending on age and mileage. A rebuilt engine at £5,500-£8,500 is well within the vehicle's value. However, the B57 engine is fundamentally robust - most owners will never need a full engine replacement. Targeted repairs (DPF cleaning, coolant pipe replacement, wastegate actuator) are usually the right answer.

• B57 engines are reliable when properly maintained
• Full engine replacement is rarely needed
• Always compare quotes before making a decision

A typical engine replacement takes 3-5 days for a specialist due to the 48V mild-hybrid system complexity - including removal of the old unit, HV system isolation, fitting the replacement, and testing. Some suppliers offer delivery on used engines, but fitting always requires workshop time.

• Supply-only: 1-3 days for delivery
• Supply & fit: 3-5 days at the workshop
• 48V system requires specialist equipment and training

Both engines produce 340 hp and 700 Nm of torque. The B57D30B was fitted from 2020-2024, while the B57D30T2 (2023-present) features updated emissions hardware to comply with Euro 6e standards. Performance is identical; the T2 variant is primarily an emissions update.

• B57D30B: 2020-2024, original M340d engine
• B57D30T2: 2023-present, Euro 6e compliant
• Both use twin-turbo, 48V mild-hybrid, 8-speed automatic

Yes - every rebuilt engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty. This covers manufacturing defects and component failure, giving you peace of mind. Always confirm exact warranty terms with your chosen supplier before purchase.

• 12-month warranty is standard across our network
• Unlimited mileage on most policies
• Supply & fit options include warranty on labour as well