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Mercedes-Benz

CLK63 AMG

C209 / A209· 2006-2009 coupe Caution

Top issues

4 known problems · 2 high

high

M156 cylinder head bolt failure

Any (age-related, not a fixed distance)

high

Camshaft lobe and hydraulic lifter wear

Owner-reported from about 160,000km

medium

Camshaft adjuster rattle

All 4 problems ↓ Inspection checklist →

At this odometer

See which of this car's known problems are due at that mileage, which should already have been dealt with, and what's coming up.

Before and after

Before: Mercedes-Benz CLK55 AMG (C209/A209, supercharged 5.4L V8)

After: Mercedes-Benz E63 AMG coupe and later C63 AMG coupe (no direct CLK successor; the CLK name ended in 2009)

Price (AUD)

$29k-$39k (unverified)

Body styles

Coupe, Cabriolet

Drivetrain

RWD

Origin

Germany

Built in

Germany

Overview

The CLK63 AMG swapped the CLK55's supercharged 5.4L V8 for AMG's own naturally aspirated 6.2L M156 V8 (badged 6.3 because it nods to the 1960s 6.3L M100). It is a CLK body with E63-class performance and a seven-speed paddle-shift automatic with no manual option. Sold as a coupe; a CLK63 cabriolet is also listed in Australian price guides, but we could not find its new Australian price, so no cabriolet figures are given here. A limited CLK63 AMG Black Series coupe was sold new in Australia from early 2008 (373kW, 630Nm, from $299,000; about 50 allocated and about 40 delivered per different Mercedes-Benz Australia statements). It is a separate, much rarer car, so its figures are not mixed into the standard car's numbers below. The big risk is the M156 itself: check head bolts and cams before anything else. Fuel tank is only 62 litres, so range is short.

Engines & variants

6.2L M156 V8 (CLK63 AMG)

Engine

All-alloy naturally aspirated V8, marketed as 6.3

Engine code

M156

Config

V8 NA

Displacement

6208cc

Power

354kW

Torque

630Nm

Drivetrain

RWD

0–100

~4.7s (unverified)

Economy

14.2 L/100km combined (unverified)

Transmission

7AT (AMG Speedshift 7G-Tronic)

Pros

354kW naturally aspirated V8 with a proper exhaust note
Short wheelbase makes it more agile than the E63 sedan
Adaptive dampers, AMG brakes and body kit standard
Rare and distinctive in Australia

Cons

62L fuel tank means short range
Real-world use over 14.5 L/100km, over 20 in hard driving
Stability control cuts in early and firmly
Big-bill M156 risks if head bolts and cams are not sorted

Known problems

high

M156 cylinder head bolt failure

Documented M156 fault on early engines: the original head bolts can corrode or stretch and break, letting coolant into the oil or combustion chamber. Reported warning signs are a low coolant light, misfires and a check-engine lamp. A broken bolt loads the others, so failure can cascade. Enthusiast and parts-supplier sources put the affected engines as those below engine number ending 60 060658 (roughly 2006 to early 2010 builds), and an Australian reference site lists head bolt failure for the CLS63 AMG and other M156 cars. Whether a given car has been updated is not shown by the build date alone.

Fix: Ask for invoices showing the head bolts were replaced with the updated bolts. If there is no proof, budget for the job or have an M156 specialist check coolant loss, oil condition and compression before buying.

Any (age-related, not a fixed distance)

high

Camshaft lobe and hydraulic lifter wear

Owner-reported: the cam lobes (intake side most often) wear against the hydraulic lifters, and the cams are reported to be softer than the lifters. Reports put it from about 100,000 miles (about 160,000km), worse with long oil-change intervals. A US class action alleges defective cam and lifter material; those are allegations only. An Australian reference site also lists camshaft lobe and valve lifter wear for the CLS version of this engine.

Fix: Ask for a full service history with short oil intervals. Have a specialist pull a valve cover to inspect the lobes. Repair means replacing camshafts and lifters, usually at the same time.

Owner-reported from about 160,000km

medium

Camshaft adjuster rattle

Owner-reported: the camshaft adjusters (intake worst) lose hydraulic pressure and rattle at cold start, then at any revs. A service bulletin is said to cover it.

Fix: Listen on a cold start. Replacement of the adjusters (and normally the related solenoid seals) is the repair.

medium

Oil leaks and crankcase breather

Owner-reported / parts-supplier sourced: valve cover, cam solenoid cover and oil filter housing gaskets commonly leak, and the crankcase breather diaphragm or hose can deteriorate, causing oil burning, misfires, smoke and fuel-trim codes. Leaks can contaminate the alternator, belt and hoses.

Fix: Check for oil around the valve covers and filter housing; replace gaskets as a set and fit a breather valve kit if there are symptoms.

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