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What to check: Mercedes CLK

Ranked across all years of the Mercedes CLK, from its own MOT record and from what owners report. Tick it off at the car.

From this model's MOT record

The physical checks its own defect data says are worth your time, most telling first.

Brake pipes underneathRuns high on this modelFollow the metal brake lines with a torch where they run along the sills and over the rear axle. White crust or flaking metal means they are corroding, and the online MOT history usually shows the same advisory creeping up for years before the fail.Recorded on 35.7% of tests at age 10-15 · class average 6.2%

Coil springsRuns high on this modelLook through the wheel spokes at the bottom coil of each spring; when springs snap it is usually there, and the break is visible. Step back and check the car sits level too. A dropped corner is often a broken spring.Recorded on 9.5% of tests at age 10-15 · class average 3.2%

Bushes and ball jointsDrive slowly over broken tarmac with the windows down and listen for clonks from either end. Back at the car, have someone rock the steering wheel while you rest a hand on each front wheel; play you can feel through the tyre is a worn joint.Recorded on 12.9% of tests at age 10-15 · class average 9.0%

Wheel bearingsRuns high on this modelOn the test drive, listen for a drone that rises with road speed and shifts when you sway the car gently between lanes. That is a wheel bearing, and it only ever gets louder.Recorded on 7.0% of tests at age 10-15 · class average 0.6%

ExhaustRuns high on this modelListen along the exhaust at cold idle for blowing or chuffing, and give the tailpipe a push to check nothing hangs loose. Small blows only get louder.Recorded on 5.8% of tests at age 10-15 · class average 0.9%

Steering playRuns high on this modelWith the engine running and the car parked, waggle the wheel lightly about the straight-ahead. The wheels should respond almost at once. A dead zone before anything happens means wear in the rack or the track rod ends.Recorded on 5.3% of tests at age 10-15 · class average 1.7%

Headlamp lensesRuns high on this modelCheck for condensation inside the headlamps and for cloudy or yellowed lenses. Both attract MOT trouble, and moisture inside a sealed LED unit generally means a whole new lamp.Recorded on 4.1% of tests at age 10-15 · class average 1.1%

Worth doing on any used car

These judge the seller's upkeep rather than the model.

Tyres, all fourCheck the tread across the full width of each tyre, inner edge included, and look for cracking and mismatched brands. A set of decent tyres is £500 or more on most cars, which makes this the easiest money to take off a price. If the pressure warning light is on, budget for sensors too.Recorded on 23.4% of tests at age 10-15 · class average 20.9%

Pads and discsLook through the wheel spokes at the brake disc. A pronounced lip on its outer edge, or a rusty and scored face, means discs and pads are due all round, a few hundred pounds on most cars. A haggling point rather than a reason to walk away.Recorded on 16.6% of tests at age 10-15 · class average 11.4%

Because of what owners report

Drawn from the owner reports rather than the MOT data. These are the model-specific ones.

Push the brake pedal hard with the engine off, then start it and check the pedal doesn't sink or feel unusually long and hard.A long, hard pedal or an SBC warning light on early W209s points to Sensotronic brake system problems.

Drive it and try several gearshifts, including a kickdown, watching for delay, flare or a sudden drop into one gear.Harsh, hesitant or stuck shifts suggest the conductor plate in the automatic gearbox is on its way out.

Test every electrical item: locking, wipers, windows, dash lights, in one go.Several unrelated electrical faults at once usually means water has got into the fuse box or SAM module.

Listen at idle and under light acceleration for a metallic rattle from the top of the engine.A rattle on 230 or 320 models is the camshaft adjuster magnet, usually cosmetic but worth a price chip.

On a convertible, cycle the roof up and down twice and check it completes smoothly with no fluid smell or leaks underneath.Hesitation, stalling partway or a puddle under the car points to failing roof hydraulics.

On a Kompressor car, floor it briefly and watch the mirrors for smoke.Visible smoke under hard acceleration suggests supercharger seals are worn.

Check the MOT history for repeated brake-related advisories or failures.Recurring brake advisories on this model line up with known Sensotronic and general brake system weak spots.

Full Mercedes CLK reliability report