BMW 3 Series 318i Engine ReplacementCompare Prices & Get Quotes

A BMW 3 Series 318i engine replacement typically costs £900-£6,500 for the engine alone, depending on condition (used, reconditioned or rebuilt) and which engine code your car has. Fitted prices through a specialist add £650-£910 in labour, while main dealer fitting can be 30-50% higher.

• Used 318i engine: £900-£1,800
• Reconditioned 318i engine: £1,500-£3,200
• Rebuilt 318i engine: £2,800-£6,500

The most common early warning sign is a metallic rattling or ticking noise from the engine on cold start, which may quieten as the engine warms up. As the chain tensioner and guides wear further, you may notice:

• A persistent rattle that doesn't disappear when warm
• Loss of power or hesitation under acceleration
• Engine management light illumination
• Low oil pressure warning (caused by broken guide debris blocking the oil pickup)
• In worst cases, the engine cranks but fails to start (chain has jumped or snapped)

It depends entirely on your car's condition and value. For a 2004-2008 E90 318i worth £2,000-£6,000, a used engine (£900-£1,500) is often the most cost-effective route, but ensure the replacement has documented timing chain history. For a 2007-2011 E90 LCI 318i worth £3,000-£8,000, a reconditioned engine (£1,800-£3,200) offers a good balance of cost and reliability. For a 2015+ B48-equipped 318i worth £8,000-£18,000, a rebuilt engine (£4,500-£6,500) with a 12-month warranty is a sound investment that preserves the car's value and reliability. Always compare the cost of replacement against the car's current market value before committing.

Both are 2.0-litre four-cylinder petrols in most generations, but the 320i produces more power - typically 156-184 hp versus the 318i's 118-156 hp. In the N43 generation (2007-2011), the 318i uses the N43B20A (143 hp) while the 320i uses a higher-tune variant of the same engine. The B48 generation (2015-2019) sees the 318i at 156 hp and the 320i at 184 hp. The 320i also typically commands a higher used value, making engine replacement more economically viable on older examples.

A typical BMW 318i engine replacement takes 8-12 hours of workshop time for a specialist, spread across 1-2 working days. This covers removal of the old engine, transfer of ancillary components (turbo on B48, injectors, sensors, wiring loom), installation of the replacement unit, and full system testing. Main dealers may take longer due to higher workload and more rigorous checklists. Supply-only orders (without fitting) typically dispatch within 1-3 working days.

If caught early (before the chain jumps or snaps), a specialist can replace the N43 timing chain, tensioner, guides and all consumable bolts for £745 including VAT. The same job at a BMW main dealer typically costs £1,800-£2,500. If the chain has already jumped or snapped, the repair cost rises significantly - often £1,500-£3,000 at a specialist - and a full engine replacement may be more cost-effective. Crucially, ensure the sump is dropped to remove any broken guide debris; skipping this step risks oil starvation and subsequent engine failure.