BMW 6 Series 645Ci Engine Replacement Compare Prices & Get Quotes

A replacement N62B44A engine for a BMW 645Ci typically costs £2,000-£3,500 for a used unit, £3,500-£5,500 for a reconditioned unit, and £5,000-£7,500 for a fully rebuilt engine with a 12-month warranty [EM-QUOTE via N63 proxy]. Supply and fit adds approximately £780-£1,040 in specialist labour (12-16 hours at £65/hr) [EM-QUOTE].

• Used engines: lowest cost, variable condition and mileage
• Reconditioned engines: restored to OEM tolerances, balanced cost and reliability
• Rebuilt engines: fully stripped and rebuilt with new components, best warranty

The most common sign is blue smoke from the exhaust on cold start or after idling, caused by oil seeping past worn valve stem seals into the combustion chamber. Other symptoms include:

• Increasing oil consumption between services (1 litre per 1,000 miles or more)
• Fouled spark plugs leading to misfires
• Failed MOT emissions tests due to excessive hydrocarbons

It depends on the condition of the rest of the car. A typical 645Ci is worth £4,000-£12,000. If the body, interior, and transmission are in good condition, a rebuilt engine (£5,000-£7,500 fitted) can extend the car's life by 80,000+ miles and is often cheaper than buying a replacement 645Ci in similar condition. If the car has rust, suspension issues, or a failing gearbox, consider scrapping or breaking it instead.

• Check MOT history and bodywork before committing
• Low-mileage, well-maintained examples justify the investment
• Convertible values typically hold better than Coupé values

Most BMW 645Ci engine replacements take 2-4 days for supply and fit at a specialist garage. The N62B44A is a relatively straightforward V8 to remove and refit on the E63/E64 chassis, though the engine bay is tight. Allow additional time if the car requires:

• Cooling system components (water pump, thermostat, hoses)
• VANOS solenoid replacement
• Exhaust manifold or catalyst work
• Collection and delivery (1-2 days depending on location)

Yes - all rebuilt and reconditioned BMW 645Ci engines supplied through EnginesMarket include a minimum 12-month unlimited-mileage warranty. Used engines typically have a 3-6 month warranty depending on the supplier. Extended warranty options are available with some specialists.

• Rebuilt engines: 12-24 month warranty, unlimited mileage
• Reconditioned engines: 12-month warranty, unlimited mileage
• Used engines: 3-6 month warranty, mileage-dependent

The 645Ci uses the N62B44A - a 4.4-litre V8 producing 333 hp. The 650i (which replaced the 645Ci in 2005) uses the N62B48 - a 4.8-litre V8 producing 367 hp. The engines share the same basic architecture and many components, but the 650i's larger displacement delivers more power and torque. A 645Ci engine cannot be directly replaced with a 650i engine without significant ECU and hardware changes.

• 645Ci: 4.4L, 333 hp, 450 Nm - produced 2003-2005
• 650i: 4.8L, 367 hp, 490 Nm - produced 2005-2010
• Engine swaps between the two are not recommended