The twin-turbo W12 engine's layout is unique among today's production cars and helps keep the weight of the motor further back in the chassis as it's shorter than a V12. Essentially two VW VR6 engines spliced on to a common crankshaft, the 5,998cc W12 has a bore and stroke of 84.0 x 90.2mm and four valves per cylinder. In its original launch form, the engine produced 560hp at 6,100rpm and 479lb ft of torque at a lowly 1,600rpm. The Speed model increased power to 610hp at 6,000rpm, but more importantly upped torque to 553lb ft at 1,750rpm. For the Supersports, power rose to 630hp and 590lb ft.
You won't want for power, that's for sure
In all three configurations, the Bentley Continental GT's engine has proved to be reliable and long lived, which accounts for there being a lot of high mileage cars out there. Several specialists have told us they would choose a well used car with full service history over one with low miles as the Continental does not like being left standing for prolonged periods.
If the car has been stored for periods, you can expect one or both of the batteries to have drained flat. The main battery performs all of the duties you expect, while the second battery is there as back-up. Be careful not to keep the ignition key too close to the car when it's parked as this can drain the battery as the car and key sensor are alerted to each other in readiness to unlock the car.
Other electrical faults can also leave the GT stranded, such as failed coil packs that seem to be a VW Group weak spot. You should spot this by an uneven engine idle and the coils can be replaced for £350 a set, while spark plugs will cost about £160 for 12. However, bear in mind the spark plugs are tricky to reach and replace as the engine is so densely packed into the bay. Luckily, the spark plugs have a four-year recommended life span.
Failed coil packs are common
Some head gaskets have been known to fail on the W12, but it's rare. If this does happen to your car, it will likely mean a £15,000 bill to remove the engine and replace the gaskets on what is supposed to be a sealed engine unit.
There should be no worries with the two turbochargers so long as the engine has been serviced with the correct 0W-40 synthetic oil. If there is any blue smoke from the exhausts, best to walk away.
Finally, check the condition of the radiator as best you can from above and below the engine bay and through the grille. Replacing a corroded or blocked radiator means removing the front bumper, which is time consuming and adds to the final bill on top of £630 for the radiator itself.
As for the six-speed ZF automatic gearbox and all-wheel drive system, they are strong and reliable. Any problems here are most likely due to a worn electrical connector, so repairs tend to be affordable rather than astronomical.
PHer's view:
"Engine is great, but you have to be certain it's been maintained. My first was a high miler with fastidious service record and it never missed a beat. The second has a low miles car and I think it had just been left standing as it needed a huge service to sort lots of niggles. Worth it in the end."
Terry Wills
