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Mercedes-Benz Mercedes-AMG A45 S common problems: what to check before you buy

Credov's researched list of the 5 faults the Mercedes-Benz Mercedes-AMG A45 S is known for (2018–2019), 5 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.

Known problems on the Mercedes-Benz Mercedes-AMG A45 S

Fuel hose can chafe and leak

Safety risk

2019–2020 · petrol · Engine

What to look for: Sniff under the bonnet for petrol at idle and after the drive, and look for wet or chafed fuel hoses.

Why it matters: Leaking fuel in a hot engine bay is a fire risk; a petrol smell is a stop-and-fix item, not something to drive home on.

Sources: 1 2

Power steering can fail suddenly

Safety risk

2018–2024 · Suspension and steering

What to look for: Check for any steering warning in the cluster, and feel for steering going suddenly heavy at low speed or when parking.

Why it matters: Sudden loss of power steering makes the car much harder to turn, especially at low speed, which is a crash risk.

Sources: 1 2

Engine won't restart after auto stop

Safety risk

2018–2019 · Engine

What to look for: Let the engine auto-stop at lights several times and check it restarts promptly every time, noting any power loss on the drive.

Why it matters: An engine that will not restart in traffic, or cuts out on the move, leaves the car stranded where it could be hit.

Sources: 1

Air-con water leaks into footwells

Costly if missed

2018–2019 · Interior and air con

What to look for: Press the carpet in both front footwells and beside the centre tunnel for dampness, and watch for airbag or engine warnings.

Why it matters: Water around the airbag and other control units causes expensive electrical faults that keep coming back until the source is fixed.

Sources: 1 2

M139 valve springs can break

Costly if missed

M139 · petrol · Engine

What to look for: Start from cold and idle warm, feeling for rough running or hard starting, and read the scan for misfire codes.

Why it matters: A broken spring can let a valve hit a piston, and the bulletin allows for valve seat or piston damage, which turns a spring job into major engine work.

Sources: 1

Got a question about a Mercedes-Benz Mercedes-AMG A45 S? Ask Credov: a noise, a warning light, a part or how to fix it.

Also check on every car

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.

Other Mercedes-Benz models

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.