Coolant Loss Due to Leak from Expansion Tank on BMW X5

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: 99,880 (10,400–247,000)
Engines affected: 3.0L 6 Cylinder, 4.4L V8, 4.6L V8, 4.8L V8, V8
9 model years affected: 2000, 2001, 2002, 2003, more2004, 2005, 2006, 2007, 2008
60 people reported this problem
Viewing 1 - 20 of 26 comments
Expansion tank was cracked. I purchased a new one and installed myself (very easy) and solved the problem. If only all of the other fluid leaks on this car were this simple....
expansion tank cracked, towed to dealership for repair, replaced with new tank, cost me over $800 in total. crazy!!! my fetal $21K mistake. Just bought last month and this car already cost me so much trouble, don't buy used BMW, I may have to trade it in for a Japanese car.
Crack down side of tank. Had to replace expansion tank
Vehicle lost all fluid instantly, luckily as I parked at my house. No overheating warning. It cost 625 to replace tank and do full coolant system test and service....at the dealer.
Hairline crack in the expansion tank, causing car to lose antifreeze.
leak from plastic fitting on engine side of hose. part # 17-12-7-509-967
I noticed it starts to overheat when i accelerate harder. If i drive it normally its absolutely fine. The temperature gauge rises and when i open then bonnet the leak is on the actual cap of the expansion tank. Could it be that i need a new cap or should i just buy a new expansion tank??
Large crack. Dealer fixed for free.
Expansion tank split at the seam. Had tank replaced at Reliable Import Service in Raleigh NC.
replaced wt new container
Hairline cracked.
I experienced a coolant leak when I had the error message on the dash for low coolant. It was the expansion tank that had cracked. All coolant parts were inspected and this was the only issue in the cooling system so far. It happened soon after I topped off the coolant in the expansion tank.
I find it completely ridiculous that people pay tens of thousands of dollars for new bmws and every single problem is a known bmw manufacturing flaw. My mechanic said he could have patched hole in my expansion tank crack if it were metal but once again bmw used inferior plastic part. I've also had the well known sunroof defect and the door handle can't open my front doors defect. Oh and the headrest defect and the gas cap defect. Cheap cheap manufacturing and parts for such a pricey car bought new. Ridiculous bmw you know there are thousands of us with same complaints.
Expansion Tank crack causing loss of coolant
Sides split on plastic overflow/fill tank. $800 to repair. Did water pump at same time--- Over $900 repair cost.
Just had the water pump replaced 2 days ago and today my coolant level light came on and have found that my coolant tank is leaking. Seems weird to me but after reading it may be a common problem...?
Hairline crack in coolant expansion tank, driver side corner
Water pump and thermostat went out first, week later, reservoir .
Had truck running charging the battery, after about 20 mins I see water gushing from underneath. I turned it off popped the hood and noticed a crack in the resivour box... Is this a recall item???
One inch hairline crack halfway down the side of the coolant reservoir. Low coolant light on dash. Not sure why this tank would crack. I've never owned another make of car that has this reservoir problem. Solution is replacing tank and hope the second tank won't fail. Never had an overheating signal on the dash.