EE20 2.0D boxer

A knock from the bottom end that grows with load, low oil pressure, and in the worst case a sudden failure with no warning at all. Early EE20 engines cracked crankshafts, and Subaru revised the design during the run. Oil dilution from failed particulate filter regenerations makes it worse, which is why short-journey cars are the ones that suffer.

Check: Find the build date and any record of engine work before you look at anything else, because you cannot hear this one coming. Treat an early car with no engine history as carrying the full risk.

Later parts: Revised crankshaft and bearing specification during the production run

Warning light, limp mode, oil level rising above the maximum mark from fuel dilution. The filter needs sustained hot running to regenerate. A car used for short urban trips never completes a regeneration cycle.

Check: Read the DPF soot load and the distance since the last regeneration on a scan tool, and check the engine oil level and smell it for diesel. Ask what the car was used for. A short-trip city diesel is the wrong car regardless of mileage.

Coolant loss with no visible external leak, white smoke, sweet smell. The EGR cooler cracks internally and leaks coolant into the intake. BMW recalled affected diesels over a fire risk from glycol deposits igniting.

Check: Check coolant level and look for unexplained top-ups in the service history. Verify the recall was carried out. It's free and searchable by VIN.