BMW M135i Engine Replacement Compare Prices & Get Quotes

A rebuilt N55B30 engine for the BMW M135i typically costs £4,000-£6,500 supply-only. A reconditioned unit is £3,200-£4,500, while a used engine is £1,800-£3,200. Supply & fit adds £600-£1,200 depending on the specialist and location.

• Rebuilt: £4,000-£6,500 (supply only)
• Reconditioned: £3,200-£4,500 (supply only)
• Used: £1,800-£3,200 (supply only)
• Labour: £600-£1,200 extra for supply & fit

The most common warning signs include oil leaks (valve cover, oil filter housing, oil pan), long cranking times or rough idling (HPFP failure), and a rattling noise from the turbocharger at low speeds (wastegate rattle).

• Oil spots under the car or burning oil smell
• Check engine light with fuel system codes
• Rattling noise on deceleration or light load

A BMW M135i of relevant age (2012-2015) typically sits in the £5,000-£12,000 value band. A rebuilt N55B30 engine costs £4,000-£6,500, which is a significant but justifiable investment - especially when the alternative is selling a non-running car at a massive loss.

• A non-running M135i sells for 30-50% of market value
• A rebuilt engine includes upgraded components the factory never fitted
• A documented specialist rebuild adds value to discerning buyers

A correctly rebuilt N55B30 engine using upgraded gaskets and components should last 100,000+ miles - often longer than the factory original. All engines supplied through EnginesMarket carry a minimum 12-month unlimited mileage warranty.

• Specialist rebuilds include upgraded gaskets and seals
• Upgraded components address the original failure points
• 12-month unlimited mileage warranty standard

The M135i uses the N55B30 3.0L turbocharged straight-six (320 hp), while the M140i uses the B58B30 3.0L turbocharged straight-six (340 hp). The B58 is a more modern engine with improved reliability and tuning potential, but the N55 remains a strong performer when properly maintained.

• M135i (2012-2015): N55B30, 320 hp, single twin-scroll turbo
• M140i (2015-2019): B58B30, 340 hp, improved design
• Both are straight-six petrol engines

A used N55B30 engine is cheaper (£1,800-£3,200) but carries the same factory flaws that caused the original failure - oil leaks, HPFP issues, and wastegate rattle. A rebuilt engine costs more but eliminates those weaknesses with upgraded components.

• Used engine: cheaper but same factory weaknesses
• Rebuilt engine: more expensive but failure points addressed
• All rebuilt engines include 12-month warranty