2007 BMW 6 Series (E63/E64)

The front rubber seal on the aluminium coolant crossover tube in the engine valley degrades. Coolant leaks through the weep hole in the timing cover. While BMW specified engine removal, aftermarket collapsible/telescopic tubes allow in-situ repair.

Symptoms: Coolant dripping from the small weep hole behind the water pump, Low coolant level warning on iDrive...

Est. repair cost: £800–£3,000

The valve stem oil seals on the 32-valve N62 V8 bake hard from high operating temperatures (105°C thermostat), allowing engine oil to run down the valve guides into the combustion chambers.

Symptoms: Plume of blue/grey exhaust smoke when pulling away after idling for 5 minutes, Heavy oil consumption exceeding 1 litre per 800 miles...

Est. repair cost: £1,500–£3,000

On the E64 convertible, the complex electro-hydraulic roof mechanism uses multiple hall sensors and microswitches that fall out of calibration or break, halting the roof mid-cycle.

Symptoms: Roof stops moving midway through opening or closing, "Top not locked" warning on instrument cluster...

Est. repair cost: £200–£800

A figure-8 shaped rubber seal behind the engine-mounted alternator bracket hardens and leaks engine oil under pressure. Replacing the inexpensive seal requires significant front-subframe or engine-mount clearance.

Symptoms: Heavy engine oil leak on the front left (passenger side) of the engine, Oil dripping onto the steering rack and lower undertray...

Est. repair cost: £500–£1,000