Models · Mercedes-Benz
Mercedes-Benz SLK55 AMG R172 buying guide
The R172 SLK55 AMG, built from 2012 to 2015, uses the M152, a naturally aspirated 5.5 litre direct-injection V8 related to the M157 biturbo, with a seven-speed automatic. Specialists regard the engine and gearbox as very durable.
The versions
- M152 5,461cc naturally aspirated V8, 421hp and 398lb ft
- Cylinder deactivation in C mode, shutting down four cylinders between 800 and 3,600rpm
- Seven-speed Speedshift Plus 7G-Tronic automatic, rear-wheel drive
- Folding hard top, with an optional glass panoramic roof
What to check on a R172 SLK55
3 model-specific things to look at when you view one. They're a starting point, not the full inspection.
Roof and boot divider latches
What to look for: Operate the roof fully open and closed at least twice. Watch that the divider between the roof storage area and the boot locks into place, because the roof won't lower until it does. Listen for creaks and rattles from the roof with it up.
Why it matters: Latches that don't seat properly in their catch can jam the roof open or closed. The roof also develops creaks and rattles over time. A roof that cycles cleanly several times is a good sign.
Ticking at idle from the exhaust
What to look for: With the engine idling and warm, stand at the back of the car and listen for a ticking sound from the exhaust area. Switch between the driving modes and listen for the exhaust note changing as it should.
Why it matters: One or both exhaust valve motors can fail, and a failed one causes a ticking sound at idle as the working valve tries to get in sync with the faulty one. The noise comes from the valve motor, not the engine.
Rear axle and brake line corrosion
What to look for: From underneath, with a torch, look at the rear axle parts and the metal brake lines running along the underside for flaking or heavy rust.
Why it matters: Corrosion on the rear axle and brake lines is becoming common as these cars age. Brake lines are a straightforward replacement, and a clean underside is a sign of a car that's been looked after.
Also in the full guide
- Water in the boot
- The cold start, test drive and paperwork checks for the exact version you're viewing
The full guide to the R172 SLK55
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.
Other generations
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.