Coolant Loss Due to Leak from Expansion Tank on BMW X3

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: 84,535 (57,000–120,000)
5 model years affected: 2004, 2005, 2006, 2007, more2008
36 people reported this problem
Viewing 1 - 18 of 18 problem details
Coolant low intermittently goes on and off. Never stays on. Mechanic (not the dealer) found a hairline crack & says it has a small leak, not enough to reach the ground. Wants to charge me $700 to replace the tank. Haven't fixed it yet - I am researching optios.
Expansion tank blew out just as I parked the car. Loud bang, then coolant just ran out all over the place. Crack on side of expansion tank must be 5-6" long.
My coolant light has just come on and when out after three days and diagnostic that couldn't detect anything. Now my service engine soon light is on.
I had the extension tank replaced about 2 years ago, and the coolant is leaking again.
Expansion tank ruptured cracked and all coolant lost. Car overheated. NO COOLANT WARNING LIGHT WHEN LOW OR EVEN WHEN COMPLETELY EMPTY. Why doesn't a BMW have any kind of warning? This car is always in for repair. Many, many problems for what is supposed to be a well-engineered car. Not so. Lots of poorly made parts that are unusually high cost to repair/replace. Not a satisfied BMW owner.
losing antifreeze constantly
Took to the dealer. They replaced the water pump under warranty (thanks for the freebie). Not until I aquired a high pressure oil leak that I noticed oil and antifreeze mixed on the garage floor. I bought an expansion new expansion tank from BMW for $116.00 ($59.00 part on the internet) and fixed the thing myself in a couplr hours.
Radiator Reservoir expansion tank broke while on the traffic. Big crack on the expansion tank. Car was sitting on traffic.
Yep, leaking coolant, drips here and there, light came on, refilled, couple weeks later light came bk on, brought into shop, he cant find leak, but is assuming expansion tank.
replace expansion tank and thermostat that connected to the tank.
Coolant light was going on and off brought in to dealer, was told the expansion tank was cracked. After examing the tank, BMW said the cylinder head was cracked and the oil was thick and tarry.

Car was serviced at an authorize mechanic at 55K.
Customer service has requested BMW enginner to inspect engine.

I got the impression they may suspect my maintaince under warranty.
Expansion tank cracked
Wasn't fix coolant light on and I think it's leaking
The coolant light is turning on/off and there is coolant leaking from underneath the car. After driving, you can smell the coolant burning from the engine.
Coolant leaking from expansion tank was causing light to go off on dash. Engine was beginning to overheat. Replaced coolant tank and spent about $140 overall for parts and repair and problem was solved.
expansion tank is leaking
Coolant light comes on and off when car up to heat funny smell,when useing heater blower.tank had a very small crack on edge near where power steering pipes run past tank. This was a very hard leak to find as it only opens up when car is warm and blower on soon as you turn car off it closed up and was only about 2mm break which is very hard to see when no pressure.
Changed tank and thermo at bottom as it breaks when removing easy d.i.y repair cost £80 on parts car works fine now