Credov's researched list of the 9 faults the Mercedes-Benz A-Class is known for (2012–2018), 8 of them serious or costly. Each one says what to look for when you check the car, so you can spot it before you buy. Not every car has these faults: they are the ones worth checking on this model.
What to look for: In stop-start traffic and on the open road, watch for N appearing on the gear display on its own, or a stall.
Why it matters: A sudden, unannounced loss of drive while under way is a safety hazard, not just a repair bill, and the fix can range from a software update to a new control unit or clutch assembly.
What to look for: Accelerate hard from a stop: revs should rise with road speed, not flare ahead of it, with no judder or whine.
Why it matters: A slipping or failing CVT often costs more to rebuild or replace than the car itself is worth, and many affected cars are scrapped rather than repaired.
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What to look for: In tight circles and pulling away briskly, listen and feel for clunks, thumps or grinding from the rear differential.
Why it matters: Mercedes' own 2015 workshop guidance says the whole rear differential assembly is replaced once this fault is confirmed, which runs into the thousands of dollars.
What to look for: Creeping in traffic, pulling away gently and in a roundabout, feel for shudder, clunks or a slipping sensation.
Why it matters: Some shudder is normal for a dual-clutch design, but thumping into gear or persistent shuddering points to worn clutch packs, which wear faster with heavy town use and are an expensive repair.
What to look for: Listen at idle for a whistle or hiss from the top of the engine, and check for a check-engine light.
Why it matters: Owners commonly need the whole valve assembly replaced more than once, often quoted at over US$1,000 at a dealer.
What to look for: Watch the temperature gauge settle and stay normal on the drive, and check for coolant crust around the pump.
Why it matters: Driving on with an overheating or unstable-running engine risks a warped cylinder head or a blown gasket, and the thermostat's position at the back of the engine makes the job dearer than it looks.
What to look for: With the engine idling, listen near the injectors for a chuffing tick and smell for exhaust fumes.
Why it matters: Left alone an injector can seize in the head or its return line can leak badly, turning a cheap washer job into a far more expensive injector replacement.
What to look for: Check the dash for a DPF warning and pull the dipstick for oil sitting above the max mark.
Why it matters: A blocked filter cuts power and can trigger limp mode, and the diluted oil that causes it also thins lubrication for the turbo and bearings.
What to look for: Lift the boot floor and press rear carpets, checking for damp, mould smell or standing water.
Why it matters: Water trapped under the carpets causes mould, rust in the spare-wheel well and electrical faults from wet wiring, and the carpets have to come out to dry it properly.
Got a question about a Mercedes-Benz A-Class? Ask Credov: a noise, a warning light, a part or how to fix it.
On top of the faults above, every Credov inspection covers the basics: fuel smell, leaks or filler rust, engine oil leaks, power steering fluid leak, drive belt cracks or squeal, rust underneath: chassis and mounts, engine mounts, engine oil level and colour, coolant level, colour and leaks, head gasket failure signs, cold start: rattle, knock or smoke, rough or hunting idle, engine running hot on gauge, gearbox or diff oil leak, swapped gearbox without lvv and more.
Researched by Credov from manufacturer recalls and service bulletins, owner reports and workshop sources. Repair prices are typical ranges, not quotes. See also fault codes and repair costs.