Coolant Loss Due to Leak from Expansion Tank on BMW 325xi

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.

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Average mileage: 119,000 (76,000–165,000)
6 model years affected: 2001, 2002, 2003, 2004, more2005, 2006
10 people reported this problem
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problem details
2003 BMW 325xi 135,000 mi,
Developed a coolant leak (white stains around top radiator hose near coolant reservoir tank) and replaced coolant hoses ($35). They have a snap fit connector built in. Did thermostat ($47) and water pump ($36) at this time then noticed a leak developed with split in a seam of the reservoir tank. It could have been jostled during repair. New reservoir tank ($45) installed . Fixed.
2004 BMW 325xi 165,000 mi,
Not a bad repair but still a pain. You can save some $$ if you get the part online. Dont pay someone to do this, if you have basic skills it can be done at home.
2004 BMW 325xi 76,000 mi,
Thermostat caused check engine light. Changed water at same time, impeller had small piece missing and small cracks. Expansion tank developed a small crack 500 miles later. Should have done it at the same time.