Cars / Mercedes-Benz CLK55 / CLK63 AMG

Mercedes-Benz CLK55 / CLK63 AMG (2003–2009)

C209 / A209 · CLK55: M113 5.4 V8 · CLK63: M156 6.2 V8

Verdict: The CLK55 is a relatively tough AMG GT with electronics and mounts as the main annoyances. The CLK63 shares the M156's head-bolt and cam/lifter story — treat it like a C63 under the skin.

At a glance

Risk 4/5 Market: CLK55 easier; CLK63 is M156-risk

Must-have records:

CLK63: head-bolt update (engine serial) and cam/lifter work
Engine/gearbox mount replacement
Convertible: roof hydraulic service

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Buy-risk rundown

Issue	Symptom	How to check	Typical cost (as of Nov 2026)
M156 head bolts (CLK63, engines up to ~1569xx 60 060658)	Low coolant with no external leak, CEL, misfire, white smoke, milky oil	Check engine serial / records for updated bolts; scan for misfires	Preventive bolt update ~€3,000–€5,000 specialist; damage can run higher [1][2][5]
M156 camshaft / lifter / adjuster wear (CLK63)	Cold-start rattle that does not quieten; ticking when warm	Cold start and warm idle listen; valve-cover inspection	Dealer-level cam/adjuster jobs commonly ~$4,500–$7,000 [3][5]
Engine and gearbox mounts (both)	Vibration, reduced power feel, misfire-like symptoms	Test drive; inspect mounts	Not yet verified [4][6]
Torque converter / auto shift quality	Jerky or harsh shifts	Test drive when fully warm	Not yet verified [4][6]
Convertible roof hydraulics (A209)	Roof sticks, leaks, low fluid	Cycle roof fully; check reservoir behind boot trim	Not yet verified [3][6]
Electronics (ASR/ABS, seats, keyless)	Warning lights, dead seat motors	Full function check and scan	Repair bills can be large; cost not yet verified [4][6]

Cost figures checked against the sources below in Nov 2026. Bracketed numbers refer to the source list.

Notes

CLK55 (M113) is generally robust if maintained; focus on mounts, rust at arches/sills, and electronics [4][6].
CLK63 Black Series is a different market — verify originality and track use separately.

Before you buy

Use our printable pre-purchase inspection checklist and get a PPI from a marque specialist.

Sources

Australian Car.Reviews, CLK 55/63 recalls and faults (accessed Nov 2026)
Mercedes LI01.30-P-051567 (M156 head bolts) via BenzBits PDF (accessed Nov 2026)
PistonHeads, CLK63 AMG used buying guide (accessed Nov 2026)
Octane, CLK55 AMG buying guide (accessed Nov 2026)
FCP Euro, M156 cylinder head service recommendations (accessed Nov 2026)
Parkers, What could go wrong: CLK AMG (accessed Nov 2026)

Last updated 2026-11-05. Costs vary by region and shop.

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