2004 BMW M33.2L PETROL

Older M3s share BMW's habit of treating expansion tanks, radiators, hoses, and water pumps as consumables. Overheating one can quickly become an engine rebuild conversation.

The rear floor can crack around the subframe mounts on hard-driven cars, especially E46 M3s. Proper reinforcement is the lasting fix.

S54 and S65 cars are well known for rod-bearing wear, especially if oil changes have been stretched or the cars have seen regular track use. Left too long, the engine can destroy itself.