I was a student that flew 4 or 5 different C152s at the school... all of them had faults. 2 of them always had a rough running engine on the left mag and I was always told that it was fine (in fact, I was told I was fine for every fault I found).
- Low voltage light.
- Doors open in flight, even after checking them properly.
- Window locks broken, so I couldn't close them.
- Mixture control would always pop out.
- Parking breaks didn't work.
- DI would never be aligned with compass for more than 30 secs.
- Radios never switched off.
- Dents all over the wings.
- Cracks in the fuselage.
- For one aircraft, I'm not sure if the carb heat worked (engine RPM never dropped - but I was told that it was working).
I guess that's normal. The C152s still flew.