BMW 5 Series 518i Engine Replacement Compare Prices & Get Quotes

For a BMW 5 Series 518i, a used M40B18 or M43B18 engine typically costs £300-£800 supply-only. Reconditioned units range from £900-£2,000, while a full rebuilt engine with warranty is £1,500-£3,000. Fitting adds approximately £400-£800 depending on the specialist.

• Used engines are the budget option - verify mileage and history
• Reconditioned offers a good balance of cost and reliability
• Rebuilt includes new components and a 12-month warranty

The most common early warning is a rattling noise from the front of the engine on cold start, which subsides as oil pressure builds. As wear progresses, the rattle may persist when idling or under load.

• Cold-start rattle is the key early symptom
• Ignoring it can lead to chain jumping timing
• If the chain snaps, the engine is usually beyond economical repair

It depends on the car's overall condition and value. A clean, low-mileage E34 518i in good condition may justify a reconditioned or rebuilt engine. However, if the car is worth under £3,000 and needs a full engine replacement, it may be more economical to sell the car for parts and buy another example.

• Factor in the car's bodywork, interior and overall condition
• A timing chain repair is nearly always more cost-effective than a full engine replacement
• For cars with significant rust or other issues, consider scrapping

A typical BMW 5 Series 518i engine replacement takes 2-3 days for a specialist workshop, including removal of the old engine, fitting the replacement unit and testing.

• Supply-only engines can be delivered within 2-5 working days
• Full supply & fit typically takes 2-3 working days
• Some specialists offer mobile fitting for simpler swaps

Both are 1.8-litre four-cylinder petrol engines, but the M43B18 (introduced April 1994) is an evolution of the M40 with improved fuel injection (Bosch Motronic 1.7.1 vs 1.3) and a slight power increase from 113hp to 115hp.

• M43 is marginally more refined and economical
• Both engines share the same basic architecture
• Parts are widely interchangeable between the two

While it's technically possible to fit a 520i or 525i engine, it's rarely cost-effective. You would need the donor engine, engine loom, ECU, exhaust system and potentially the gearbox and rear axle. The 518i's M40/M43 engines are reliable and economical; a well-maintained example is often the better choice.

• Engine swaps require significant expertise and parts
• Insurance implications and declaration are mandatory
• Most owners find it cheaper to buy a 520i or 525i outright