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

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: 110,581 (11,000–230,000)
8 model years affected: 1990, 1995, 2001, 2002, more2003, 2004, 2005, 2006
114 people reported this problem
Viewing 1 - 20 of 57 comments
Coolant Loss Due to Leak from Expansion Tank
Coolant warning sign on. thermostat ok in the middle range, but overheated in the engine.
Coolant reserve tank is cracked. Replace once and within 6 mos happened again
coolant light will come up evry 2 days, had to keep refilling it.
The coolant would leak when the car sat idle in a parking lot or at home in the garage. I filled coolant and it would leak right after I drove the car. The coolant low sign in orange would show on the dashboard. Initially I though my battery fluid was low or the batter alternator was not charging my battery. But soon I found the issue. So I had to change the coolant bucket as that was leaking the coolant slowly.
Had a low coolant light on when starting shut it off had low coolant.put some water in temporally was leaking out as soon as I filled it took to Midas they replaced tank did a flush and new coolant for 345.00. The crack was right down the middle of tank hard to see till tank was removed
Car overheated without warning with white smoke coming out of the tail pipe. Replaced water pump, thermostat, upper and lower radiator hoses, fan switch and problem still not completely resolved. Coolant sensor disintegrated in expansion tank.
overheating, already changed t*stat, radiator fan sensor , and temperture sensor
cooling system fails, continually runs hot, even after thermostat replacement
justbought vehicle 2 monyhs ago......as temperature stated to rise in Houston...car started to run low on Coolant...have to replace weekly..
I just bought me a really nice 2001 BMW 325I, well I had it for one day and than it started to overheat. I didn't know why it was overheating, and didn't realize that the coolant is low. By the time i was able to add the coolant in it, it was too late. My car was damaged and damaged bad. Well the car broke down basically, it wouldn't start. So I had to get a tow and towed it to my mechanic. The story is BLOW GASKET, HEAD GASKET CRACKED, all because of a simple problem. So sad, repairs costly, est round 3k!!!!
Running hot due to leaky coolant extention tank. Replaced it only to find out the real problem that caused the car to run hot in the first place was the thermostat and water pump were malfunctioning. After replacing all three and a $1200 repair bill, it's now running fine.
Needed a new expansion pump and hose.
Leaking don't know if its coolant tank or raditor
Coolant reservoir had a hairline fracture and was leaking coolant.
Coolant gone after ten minutes of driving. Not fixed
Tank cracked leaking coolant. Replaced
Hairline crack in expansion tank. going to replace it this weekend. wish me luck....
Water pump fail followed by coolant reservoir fail.
Car overheated suddenly, all warning lights came on because coolant had leaked. Expansion tanks were replaced and 4 months later, after only 400 additional miles driven, problem occurred again. Sitting in the shop now.