BMW Z4 20i Engine Replacement Compare Prices & Get Quotes

A BMW Z4 20i engine replacement typically costs £1,300-£3,600 supply-only for rebuilt N46 or N20 units, or £2,500-£5,500 fitted by a specialist.

• Used N46B20 engines: £800-£1,600 depending on mileage and condition
• Used N20B20A engines: £1,000-£2,200
• Reconditioned N46/N20 units: £1,300-£2,800 with 12-month warranty
• Rebuilt N46/N20 engines: £1,800-£3,600 with upgraded components
• Professional fitting adds £800-£1,500 depending on workshop rates

Yes - the N20B20A engine in the E89 Z4 sDrive20i is known for timing chain guide failure. The plastic guides can break, causing chain slack and catastrophic engine damage. This is particularly prevalent on engines produced before 2015. Symptoms include a rattling noise on cold start and a "tractor-like" sound from the engine. If you hear these sounds, do not drive the car - have it inspected immediately. Preventative chain replacement is far cheaper than a full engine replacement.

The N46B20 is generally reliable when properly maintained, but it has age-related issues. The most common problems are oil leaks from the valve cover gasket and oil filter housing, timing chain tensioner wear, and cooling system failures. Regular oil changes using the correct specification oil and prompt attention to leaks are essential to N46 longevity. The N46 is not as problematic as the N20's timing chain issue, but it requires proactive maintenance.

The most common signs are a rattling noise on cold start that may diminish as the engine warms, a "tractor-like" sound from the engine, and in advanced cases, the engine management light illuminating with camshaft correlation codes. If you notice any of these symptoms on your Z4 sDrive20i, do not drive the car - have the timing chain inspected immediately. Ignoring the rattle can lead to complete engine destruction.

For an E89 Z4 sDrive20i worth £6,000-£14,000, a £2,200-£3,600 rebuilt N20B20A engine can make financial sense if the body, gearbox and interior are sound. For an E85 Z4 2.0i worth £3,000-£6,000, carefully evaluate whether a rebuilt engine is financially sensible - for a car in excellent condition, the investment can be justified. A rebuilt engine with warranty offers peace of mind that a high-mileage used unit cannot match.

The E85 Z4 20i (2005-2008) uses the N46B20 naturally aspirated 2.0-litre four-cylinder producing 150hp. The E89 Z4 sDrive20i (2011-2016) uses the N20B20A turbocharged 2.0-litre four-cylinder producing 184hp. They are completely different engine families - the N20 is turbocharged with direct injection, while the N46 is naturally aspirated with port injection. When ordering a replacement engine, ensure you match the correct engine code to your Z4 20i's generation.