I have a 2005 base model and have had to replace the thermostat gasket for the second time already,first one was under warranty but not the second leak that was at 100,000 Km which is 60,000 miles for U.S. When I removed the thermostat housing,the gasket was breaking up,very dry and Brittel. Seems to
be a bad part,anybody had that happen so frequently ?

 

I think this should be in the first Generation catagory.
MINI redesigned the gasket and is now an opaque color. If you do not have the new gasket that would definately be your problem. If you do have the new gasket it may be a warped housing.
Steve