Used Mercedes-Benz C-Class buying guide (1993 to 2024): which one to buy and what to check

Which used Mercedes-Benz C-Class should you buy?

The W205 (2014 to 2021) is the one to buy, because its serious known faults are in the automatic gearbox, the brake pipes and two recalls: the power steering motor on 2014 to 2016 cars and the steering column airbag wiring on cars up to 2017. The 1.8 petrol's timing chain fault covers 2002 to 2013 cars, but the 2.1 CDI injector fault and the V6 diesel oil cooler fault both reach 2014, so a 2014 diesel doesn't escape the checks you'd give a W204.

A W204 (2007 to 2014) is the harder buy. Its electronic steering lock or ignition switch can fail around 38,000 to 42,000 miles and immobilise the car, brake pipes corrode from 45,000 miles, the 7G-Tronic automatic on 2011 and later cars has a serious known fault, and the 1.8 petrol, the 2.1 and 3.0 diesels and the V6 petrols carry one too. If it has to be a W204, the 3.0 V6 CDI is the engine to look at, as long as no oil's leaking between its cylinder banks.

The older cars, from 1993 to 2008, need the most checking, mainly for rust. Rear wheel arches, body seams, screen surrounds and boot lids corrode between 70,000 and 100,000 miles on 1993 to 2007 cars, and the lower front suspension arms rot from the inside. On top of that, 1993 to 2000 four-cylinder petrols suffer failing cylinder head bolts, and 2000 to 2003 automatics with a Valeo radiator can let coolant into the gearbox and destroy it.

Which C-Class engines and gearboxes are the safe choices?

The 3.0 V6 CDI is the lesser-risk engine on a W204, because its serious fault shows itself: the oil cooler seals between the cylinder banks leak between 60,000 and 100,000 miles on 2005 to 2014 engines. Get a torch on the valley between the cylinder heads and on the undertray for oil, and sniff for burning oil in the cabin. If there's oil down the back of the engine, don't buy it.

Treat the 2.1 CDI (OM651) in the C220 CDI and C250 CDI with caution. Its piezo injectors crack on 2009 to 2014 cars, and on 2009 to 2012 engines they fail between 40,000 and 80,000 miles, throwing the car into limp mode with a heavy misfire. Mercedes told dealers to replace them when owners complained. Its timing chain sits at the back of the engine and stretches with no set interval, so a cold-start rattle that fades after 10 to 20 seconds rules the car out.

The 1.8 Kompressor and CGI petrols (M271) are the ones to avoid. On 2002 to 2013 engines the single-row chain stretches until it skips teeth between 60,000 and 90,000 miles, wrecking the valves, and 2000 to 2008 engines also build carbon under the valves, which can burn them out. The 3.5 V6 petrol (M272) isn't the answer either: it wears away its balance shaft gear between 60,000 and 90,000 miles on 2004 to 2008 cars, and on 2007 to 2014 V6s the same wear means taking the engine out.

The 7G-Tronic and 9G-Tronic automatics on 2011 to 2019 cars have a serious known fault: jamming in one gear, shuddering, lurching at low speed or losing the torque converter, anywhere from 27,000 to 108,000 miles. Mercedes first said the 7G-Tronic was filled for life, but it wants fresh fluid and a filter every 40,000 miles or 48 months, and the 9G-Tronic wants its fluid changed every 60,000 miles or 72 months, so ask for those invoices. A manual isn't touched by that fault.

What should you check when viewing a used C-Class?

Insist on seeing the engine stone cold, because the chain faults give themselves away at start-up. A metallic rattle for 3 to 5 seconds on a 1.8 Kompressor or CGI means the chain's stretched, and on a 2.1 CDI a rattle that clears after 10 to 20 seconds means the same. On a diesel up to 2008, a paraffin smell inside the car or a chuffing noise around the cylinder head points to leaking injector seals.

Get down with a torch. Brake pipes corrode on 2007 to 2019 cars from 45,000 miles, so look along the underside for crusty pipes. On anything up to 2007, check the rear arches, the bottoms of the doors, the screen surrounds, the boot lid seam and the front and rear suspension arms, as two 2004 cars had suspension arms rust through and collapse. On a 2000 to 2007 estate, open the tailgate and look for rust spots by the drain holes underneath.

On the drive, a 7G-Tronic or 9G-Tronic that sticks in a gear, judders or jumps harshly between gears is showing the known fault, so don't buy it. Start the car several times on a 2007 to 2014 model, since a failing steering lock stops it starting and leaves the wheel locked. On a 2014 to 2016 car, heavy steering or a power steering warning points to the motor in the rack, and one 2016 owner was told the whole rack had to go.

Ask for proof of the recall that fixed a broken steering column spring and poorly earthed wiring that could fire the driver's airbag on 2011 to 2017 cars, and of the power steering motor recall on 2014 to 2016 cars. Look for gearbox fluid invoices, receipts for any steering lock, injector or timing chain work, and brake pipe advisories on old MOT certificates. On Fire Opal Red cars from 2012 to 2019, inspect the boot lid and roof for blisters, white blotches or peeling lacquer.

Paste the advert into the free check and it runs these against the listing, the MOT history and the DVLA record before you travel.

Is a used Mercedes-Benz C-Class W202 (1993 to 2008) worth buying?

It's worth buying only once you've been underneath, because rust decides these cars: arches, seams, screen surrounds and boot lids corrode between 70,000 and 100,000 miles on 1993 to 2007 cars, and rear arches have perforated after 7 to 8 years. These years cover the original car and the W203 that followed from 2000, and early W203s up to 2002 were built without sealant in their door and panel seams. A good one's a five-star Euro NCAP car from the 2002 tests.

The original cars from 1993 to 2000 carry two serious engine faults. Four-cylinder petrols suffer failing cylinder head stretch bolts, which means taking the head off, and the warning signs are oil weeping from the head, overheating and coolant loss. Diesels such as the C250 TD have glow plugs that fail around 50,000 miles and snap as they're being pulled out, so a poor cold starter is a bad sign. Catalytic converters on C180, C200 and C220 petrols fail early too.

From 2000, the 1.8 Kompressor is a weak point. It builds carbon in its valve guides, bringing misfires, heavy fuel use and a warning light, and from 2002 its chain stretches from 60,000 miles. One owner paid £1,300 for a new chain on a 2006 C180 Kompressor, which still ran unevenly. A small number of 180 and 200 Kompressors have lost their superchargers after 5 to 6 years. Automatics from 2000 to 2003 with a Valeo radiator can let coolant into the gearbox and wreck it.

The diesels need care as well. Glow plugs have failed at just 3 years old, C220 CDI turbos have gone after around 6 years, which is why yearly oil changes matter, and leaking injector seals coat the top of the engine in carbon. One owner's 130,000-mile 2004 C220 CDI flagged a Sensotronic brake pump fault, and he paid £880 after Mercedes covered half the £1,760 bill. Uneven wear on the nearside front tyre points to worn front suspension bushes.

What goes wrong on the Mercedes-Benz C-Class W204 (2007 to 2014)?

The electronic steering lock or ignition switch can leave a W204 stranded: it gives up around 38,000 to 42,000 miles on 2007 to 2014 cars, the car won't start, the wheel stays locked and it has to be recovered to a Mercedes garage while parts come from Germany. One owner paid £520.80 for a new lock on a 38,000-mile 2011 C220, and another was billed £700 for the same job.

Its engines carry the heavy faults. The 2.1 CDI's piezo injectors started cracking in later 2009, and replacements were so scarce that plenty of cars sat idle for long spells. One C220 CDI that had needed new injectors locked up its engine at 28,000 miles. Owners of 2010 C180s have needed timing chain work at 42,000, 45,000 and 50,000 miles, and chains have failed outright on a 2011 C180 CGI at 70,000 miles, despite a full service history, and a 2010 C250 CGI at 80,000 miles.

Automatic gearboxes give W204 owners plenty of grief. One owner paid £396 after a 2008 C220 CDI stuck in third and lurched at low speed, another paid £240 for software and £270 for fresh fluid on a 2012 C180 CGI that still jumped between gears, and a three-year-old C250 CGI estate needed a torque converter under warranty. When it's all working, the estate's a comfortable, refined car with neat styling.

Inside, the plastic handle on the driver's door snaps, and since it's built into the door panel, the whole panel has to be replaced. Artico seat covers split along their seams between 50,000 and 80,000 miles, sometimes again after replacement, and Fire Opal Red paint on 2012 to 2014 cars blotches, blisters and sheds its lacquer. One owner of a 2010 C250 had a media interface unit fail with no spares available, leaving it without satnav, radio tuning or Bluetooth.

What does a used Mercedes-Benz C-Class cost to run?

What do C-Class owners like about them?

The W205 is quieter and nicer to drive than the W204 it replaced, and its cabin feels a big step up in quality, with a dashboard and driving position that are nicely laid out. Its four-cylinder diesels are smooth and hushed, the estate's got more room inside than the old one, and the rear seat back splits in three. On a W204, you don't need a garage to reset the service indicator: there's a sequence on the column stalks.

The 2016 coupe rides firmly but doesn't crash over bumps, it stays steady and quiet at motorway speeds, and its boot takes a big pushchair. The cabriolet's fabric roof keeps the cold out in winter, its cabin feels solid and nicely finished, and the roof works on the move up to 30mph. Older cars can last, too: one 2006 C180 Kompressor estate's exhaust went 245,000 miles before the catalytic converter casing cracked.

• The galvanised body of this model originally came with a 30-year conditional warranty against corrosion.
• Cars from 1998 and 1999 achieved 11th place in a 2001 customer satisfaction survey.
• Mercedes-Benz was rated as Britain's second most claim-free used car brand by Motor Warranty Direct.
• This model recorded a very low death rate of 2 out of 9 points from accidents.
• This model achieved an excellent score of 31 points in the 2001 Euro NCAP crash safety tests.