What to watch for on the Mercedes-Benz C-Class

The C-Class is the most accessible Mercedes with classic rear-wheel drive, and there are many used ones on the market, both in Germany and elsewhere. But a prestige badge doesn't mean every car is in order, and repairs tend to cost more than on ordinary compacts. Here is a general overview of what owners talk about for each generation. It is a list of places to look and questions for the seller, no substitute for fault statistics. Always check a specific car against the pre-purchase checklist, ideally at a garage that knows Mercedes.

Generations. W203 (2000–2007), W204 (2007–2014), W205 (2014–2021) and W206 (from 2021). Estates have their own designations (S203, S204, S205, S206), the technology is the same.

Rust on the W203. The older C-Class has a reputation for rusting more than you would expect of a Mercedes. Look at the door edges, the boot lid, the wheel arches, the sills and around the jacking points. The W204 and later are markedly better, but an inspection from underneath always pays.

Diesels.

• The four-cylinder OM646 (220 CDI and 200 CDI, W203 and early W204) has injector seal problems on some engines. When a seal leaks, black deposits form around the injectors and you may smell exhaust gases in the cabin. Look under the engine cover.
• The newer OM651 (2.1 l, W204 and W205) is very common. On some older cars injectors came up, and some were covered by a recall. Ask about the history and about the timing chain, and listen to a cold start.
• On all diesels watch the particulate filter, EGR valve, turbo and, on newer engines, the AdBlue system.

Petrol engines. The four-cylinder M271 with a supercharger or turbo (W203, W204) has timing chain and tensioner problems on some engines. The six-cylinders are pleasant, but repairs cost more. On the newer turbocharged four-cylinders M274 and M264 watch for oil leaks and the condition of the chain.

Gearboxes. The seven-speed 7G-Tronic automatic (from the W204) needs an oil change. Some cars have trouble with the gearbox control plate, showing as hard shifts or limp mode. On the test drive watch whether the gearbox shifts smoothly up and down. The newer 9G-Tronic (W205, W206) needs regular servicing as well.

Electronics. A Mercedes has many control units. Try everything: air conditioning, windows, locks, lights, navigation and assistants. On the W206 some owners complain about software errors on the large display. Diagnostics before buying make good sense here.

Suspension. The arms and bushes on the front axle wear out, so listen for knocking and watch the tyre wear. On versions with air or adaptive suspension (less common) check that it works correctly and the car stands level.

History. Many cars are imports. Check the VIN, service history and mileage. On cars with high mileage the condition of the driver's seat, steering wheel and pedals should match.

Current offer and prices. The page Used Mercedes-Benz C-Class shows how many C-Classes are on offer and for how much. You find the price development in Price trends.

Do you drive a C-Class? Write the generation, engine and mileage and what cost you the most money on the car. Experiences with rust on the W203 and with the 7G-Tronic gearbox are welcome too.