Colling loss
 

Hello I am new to the forum. I have a 08 Mini and I am having a problem with loosing coolant. It has a new thermostat housing and associated tubing. When I drive the car I lose coolant. I can not locate where it is going. I can put coolant in to the top fill level and let set and idle for 90 plus minutes. The level come up as it heats up and when the thermostat open it drops back down to normal. and stays at that point. The cooling fan comes on at the correct temperature.. I have a Foxwel reader that allows me to monitor the coolant temperature. When I did the idle test the fluid level stayed the same. A few days later I drove it to the store and when I got there it was down about 1/2 inch. When I got home it was down about another 1/2 inch. When it cooled the level had dropped to the bottom fill line.. I am going to replace the coolant cap today to see if that helps. The current cap seems to seal and hold pressure. I have the advantage that I have other cars to drive while i work on this.

Does anyone have any suggestions

Thanks
Ron.

I just realizes I can't spell. In the heading I put Colling loss instead of Cooling loss. Can this be corrected ?

Ron

On my 2022 F56 I had a similar problem then it got worse. Radiator seam crack.........New radiator under warranty.