Coolant Loss Due to Leak from Expansion Tank on BMW 330i

Problem Description and Possible Solution

An engine coolant leak may develop from the expansion tank resulting in engine overheating. When a cooling system component fails the entire cooling system should be inspected. It is not uncommon to find additional component have failed or are leaking.

Overheating can cause severe engine damage. If the engine begins to overheat it is recommended to stop at the first available location and have your vehicle towed to a repair shop.

Problem Data
RepairPal Verified
Average mileage: 111,640 (45,500–160,000)
5 model years affected: 2001, 2002, 2003, 2004, more2005
14 people reported this problem
Viewing 1 - 3 of 3 comments
Expansion tank leaks
Expansion tank required replacement.
Crack in tank was a little difficult to spot. It developed very quickly and became a real gusher. Curiously, even though I believe both the replacement tank and the old cap were OEM, the old cap did not fit the new tank, so had to wait to obtain a new cap.