The 6,208cc M156 V8 engine has a bore of 102.2mm and a 94.6mm stroke, and four valves per cylinder. This creates 457hp at 6,800rpm and 442lb ft of torque at 5,000rpm in standard form and, while there are 487, 507 and 520hp variations on the theme, we'll deal with them as a whole as the problems to watch out for are common to all.
Quite a few variants; all are marvellous
Beforehand, it's worth noting the differences between the earlier Performance Pack (PP) and Performance Pack Plus (PPP). The earlier PP did not increase engine power, but the later 2009-on PPP did up power to 487hp by borrowing some internal components from the SLS. The 507's engine used the PPP motor but with revised ECU engine management to raise power to 507hp. The Black Series cars have a 517hp version of the engine.
Cylinder head bolts on engines in cars built between 2008 and 2011 can break and cause the cylinder head gasket to fail. This will wreck the engine, though Mercedes has replaced motors under warranty. It's a problem that has been more prevalent in the USA than Europe and is also rare, so it should not be an issue.
Camshaft lobes can wear, which is caused by the cam lifters failing and putting too much stress on the lobes. If this happens, you'll be looking at a top end rebuild of the engine, though a good independent specialist should be able to carry out this work for much less than a franchised Mercedes dealer. Also, a specialist will be able to spot potential trouble in this area and steer you away from a car with impending problems. Also, listen for a rough running engine at idle as it could be a leaking intake manifold.
Will need fuel. Lots and lots of fuel
The C63 is sensitive to the fuel it uses, so best to use a premium unleaded. Most owners prefer Shell V-Power and they also report you'll be lucky to see 300 miles from a tank as a large V8 engine is never going to be the most economical. Expect around 20mpg in mixed driving. Also expect to keep an eye on the oil level and top it up as needed.
The AMG Speedshift Plus 7G-Tronic seven-speed automatic gearbox is generally tough and up to the job of dealing with the engine's power. Pre-facelift cars feature a conventional torque convertor and three shift modes - Comfort, Sport and Manual - and automatic downshift blipping. Post facelift the C63 got AMG's Speedshift MCT transmission, the torque convertor replaced with an automatic lock-up clutch for faster shifts and an additional S+ automatic mode included. However, the gearbox in facelifted cars is more prone to overheating during hard driving due to the revised front bumper design not allowing as much cooling air into the radiators. This can be cured by fitting the Black Series cooling upgrade, though this is not cheap as you'll also need a Black Series front bumper with its additional cooling apertures to make this conversion work properly. Using all new parts from Mercedes, this could set you back more than £5,000.
Aside from ECU upgrades that can free up 60- to 70hp, supercharging is a popular route to more power. Weistec Engineering in the USA offers a range of superchargers for the W204 C63 delivering anything from 640 to 770hp for prices between £9,000 and £11,000, though you will also have to factor in the cost of having these kits professionally fitted.
PHer's view:
"I found the running costs perfectly reasonable for such a car - servicing through MB service plan was entirely reasonable compared to the likes of top end Audis, fuel consumption for such a large engine was amazing really (24mpg on a 200-mile run that was very enthusiastic!). Gearbox isn't the best out there but didn't spoil the driving experience in my opinion.
Rick Wiblin