BMW X5 35i Engine Replacement Compare Prices & Get Quotes

A full BMW X5 35i engine replacement typically costs £2,800-£4,800 supply-only for rebuilt N55B30 units, or £4,500-£6,500 fitted by a specialist.

• N55B30 rebuilt supply-only: £3,800-£4,800 depending on mileage and condition
• Used N55B30 engines: £1,200-£2,800
• Professional fitting adds £800-£1,500 to any engine purchase

The N55 is generally more reliable than its twin-turbo predecessor, the N54. However, it has well-documented weak points: High-Pressure Fuel Pump (HPFP) failure is common between 50,000-80,000 miles, valve cover gasket leaks are frequent from 60,000 miles, and timing chain tensioner wear can occur on higher-mileage units. With proactive maintenance, the N55 is a durable and enjoyable engine.

The most common signs are long cranking times before the engine starts, rough idling, hesitation or stumbling under acceleration, loss of power, and the Check Engine Light illuminating. In extreme cases, the engine may stall while driving or fail to start at all. If you notice any of these symptoms on your X5 35i, have the HPFP inspected immediately.

The N55 engine is not as prone to catastrophic timing chain failure as the N47 diesel, but timing chain tensioner wear is a known issue on higher-mileage units. Symptoms include a rattling or slapping noise from the engine, especially during cold start-up. If you hear this noise, have the tensioner inspected - replacement is far cheaper than a full engine rebuild.

For an X5 35i (E70 or F15) worth £6,000-£18,000, a £2,800-£4,800 rebuilt N55 engine can make financial sense if the body, gearbox and interior are sound. The N55 is a well-supported engine with good parts availability. Always factor the 12-month warranty into your replacement decision - a rebuilt engine with warranty offers peace of mind that a high-mileage used unit cannot match.

The sDrive35i is rear-wheel drive only (available on the F15 generation), while the xDrive35i is all-wheel drive. Both use the same N55B30 engine with the same power output (306hp). The drivetrain difference affects handling and fuel economy but does not change the engine itself. When ordering a replacement engine, the same N55B30 unit fits both sDrive and xDrive variants - though fitting labour may differ slightly due to drivetrain component access.