Coolant Loss

fastsoup · 03-25-2023, 11:57 AM

Howdy,

2011 X3 35i - have a mysterious coolant leak. At first I thought it was the cap (because it wouldn't "click) so I replaced it with a OEM and the new one didn't" click"either on full close. So today I went to order a new expansion tank and noticed that the sensor below was covered in crude. I wonder, can I be losing coolant from the sensor? I have attached some photos...and appreciate the help.

deyrag · 03-27-2023, 07:23 AM

Yes, fairly common failure. If you replace it be careful with the plastic vent hose as it gets very brittle

fastsoup · 03-27-2023, 08:50 AM

Ended up being the expansion tank...no visible leak but possibly the top where the cap screwed on (no click) or gasket for the temp sensor. I just replaced the expansion tank...now tank "clicks" when cap fully sealed.

03-25-2023, 11:57 AM	#1
fastsoup Enlisted Member 9 Rep 48 Posts Drives: 2011 X3 35i M Sport Join Date: Jan 2013 Location: Vancouver iTrader: (0)	Coolant Loss Howdy, 2011 X3 35i - have a mysterious coolant leak. At first I thought it was the cap (because it wouldn't "click) so I replaced it with a OEM and the new one didn't" click"either on full close. So today I went to order a new expansion tank and noticed that the sensor below was covered in crude. I wonder, can I be losing coolant from the sensor? I have attached some photos...and appreciate the help. Attached Images Last edited by fastsoup; 03-25-2023 at 01:42 PM..
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03-27-2023, 07:23 AM	#2
deyrag Private 15 Rep 79 Posts Drives: x3 2.8i Join Date: Sep 2017 Location: ma iTrader: (0)	Yes, fairly common failure. If you replace it be careful with the plastic vent hose as it gets very brittle
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03-27-2023, 08:50 AM	#3
fastsoup Enlisted Member 9 Rep 48 Posts Drives: 2011 X3 35i M Sport Join Date: Jan 2013 Location: Vancouver iTrader: (0)	Ended up being the expansion tank...no visible leak but possibly the top where the cap screwed on (no click) or gasket for the temp sensor. I just replaced the expansion tank...now tank "clicks" when cap fully sealed.
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