Models · Mercedes-Benz
Mercedes-Benz CLK55 and CLK63 AMG buying guide
AMG's CLK coupé and cabriolet came first as the CLK55 with a 5.4 litre V8 on the C208, then the C209 CLK55 from 2002, and from 2006 the CLK63 with the 6.2 litre M156 V8, including a limited Black Series coupé.
The versions
- CLK55 (C208, from 2000): 5.4 litre V8, 342bhp
- CLK55 (C209, 2002 to 2006): 5.4 litre V8, 367bhp, five-speed automatic with Speedshift paddles
- CLK63 (C209/A209, 2006 to 2010): M156 6,208cc V8, 475hp, seven-speed 7G-Tronic automatic with paddles
- CLK63 Black Series coupé (2007): 507hp
- Coupé and cabriolet, rear-wheel drive
What to check on a CLK55 or CLK63 AMG
3 model-specific things to look at when you view one. They're a starting point, not the full inspection.
Rust in the known places
What to look for: Look closely at the rear wheel arches, the sills, the front wings, the door bottoms and the boot lid. Look behind the bodykit and undertrays where you can. Bubbling paint or flaking metal in these spots is the thing to note.
Why it matters: Rust is the main bodywork issue on these cars. The C209 was much better protected against corrosion than the C208, so earlier CLK55s need the closest look. A car with clean arches and sills, or proof of good repairs, is a sign of one that's been looked after.
Gearbox behaviour from cold
What to look for: With the engine cold, cycle through the gears and listen for shunts or knocks. On the drive, feel for juddering or harsh downshifts in the lower gears. On a CLK55, check the first gear selection doesn't stick. Ask whether the radiator has been replaced on early CLK55s.
Why it matters: On the CLK55's five-speed, the selector can stick in first, a relatively simple fix, and early cars with the original Valeo radiator can leak coolant into the gearbox. The CLK63's seven-speed 7G-Tronic can suffer a failing conductor plate and valve body, which shows as juddering and harsh low-gear downshifts; post-2009 cars are reported as better.
CLK63 head bolts and valve lifters
What to look for: On a CLK63, ask for the engine number and check it against the published list of engines that have had the head bolt and lifter updates. Listen for a rattle on a cold start, and check for low coolant, an unusually high oil level, misfiring or white exhaust smoke once warm.
Why it matters: On early M156 engines, cylinder head bolts can corrode, stretch and break, most often at the back of the engine. The valve lifters can seize instead of spinning and wear the camshaft lobes, typically around 100,000 miles. Mercedes replaced both, so many engines have been done. A cold-start rattle can also point to the camshaft adjusters.
Also in the full guide
- Engine and gearbox mounts
- The cold start, test drive and paperwork checks for the exact version you're viewing
The full guide to the CLK55 or CLK63 AMG
The CrankSight guide walks you round the car on your phone at the viewing, with every check for the exact version you're looking at: what to look for, where to find it, and what anything you find is likely to cost. As you go it builds an assessment of that car, and if you view more than one, it lines them up side by side.
£29 for the model, used on as many cars as you like, delivered within 72 hours or your money back.
General points for the model, last checked October 2026. Every car is different, so treat this as a guide to what to look at, not a verdict on any car. CrankSight is independent and has no connection with Mercedes-Benz.