Credov's researched list of the 2 faults the Audi A4 (B9) is known for (2016–2021), 2 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: Ask for both rear axle recall records, and feel the rear tyres for uneven or inner-edge wear.
Why it matters: Australian register REC-001665 (September 2021): out-of-spec rear axle nuts can break, letting the wishbone and hub carrier move and the rear axle steer itself. REC-005076 (March 2022): the first repair can misalign the axle, causing rapid tyre wear and a possible sudden flat.
What to look for: Check the coolant tank is at the mark, and look below the intake side of the engine for pink crust.
Why it matters: A slow coolant leak is easy to miss on a quick look and, left alone, risks overheating the engine; a documented pump replacement or a confirmed leak materially changes what a fair price for the car is.
Sources: 1
Got a question about a Audi A4 (B9)? 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.