IsItAGoodCar
Reliability Guide

Common Problems with the
2003 BMW 6 Series (E63/E64)

The 6 Series returned to UK showrooms in December 2003 as the E63 coupé, initially only as the 333PS 645i V8. It shared the E60 platform and iDrive, and its flame-surfaced styling made it a genuine head-turner.

What changed for 2003

  • •645i with the 4.4-litre N62 V8, six-speed manual, automatic or SMG
  • •E63 coupé only at launch; no six-cylinder or diesel option yet
  • •Aluminium doors and bonnet, carbon-reinforced plastic boot and front wings

Common MOT watch-outs

  • !Xenon headlamp levelling and adaptive light faults
  • !Corroded rear brake pipes and worn rear subframe bushes
  • !Uneven tyre wear from worn front thrust-arm bushes
3
Known Issues
2
Serious
1
Moderate
0
Minor

All Known Issues

V8 Coolant Pipe Leak (N62)

SeriousCooling System

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.

Est. Repair Cost: £800–£3,000
Warning Signs:

Coolant dripping from the small weep hole behind the water pump, Low coolant level warning on iDrive, Sweet coolant scent after parking

What to Inspect:
  • Shine a torch behind the water pump pulley to look for dried white or blue coolant tracks
  • Ask if a BimmerFix or All-Trac expanding stent pipe has been installed
Verified by IsItAGoodCar Research TeamUpdated

Valve Stem Seal Leak (N62)

SeriousEngine

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.

Est. Repair Cost: £1,500–£3,000
Warning Signs:

Plume of blue/grey exhaust smoke when pulling away after idling for 5 minutes, Heavy oil consumption exceeding 1 litre per 800 miles, Fouled spark plugs and catalytic converter degradation

What to Inspect:
  • Idle the warm engine for 5–7 minutes, then rev to 3,000 rpm and observe exhaust
  • Check MOT emissions history for borderline HC levels
Verified by IsItAGoodCar Research TeamUpdated

Alternator Bracket Oil Leak

ModerateEngine

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.

Est. Repair Cost: £500–£1,000
Warning Signs:

Heavy engine oil leak on the front left (passenger side) of the engine, Oil dripping onto the steering rack and lower undertray, Burning oil smell while stopped in traffic

What to Inspect:
  • Inspect the underside of the alternator for fresh engine oil coat
  • Check left-side front suspension arms and subframe for oil contamination
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2003 BMW 6 Series (E63/E64)

  • Check the iDrive screen and every menu for reboots or dead pixels
  • Listen for timing chain tick from the V8 and check for oil leaks
  • Verify the service history uses the correct long-life oil and intervals
2004
Check a 2003 BMW 6 Series (E63/E64) by Registration