I own a 2005 Mini Cooper (non-S) and in its third year it developed a small antifreeze leak and they (BMW dealer) found the problem to be a distorted thermostat & housing which was replaced under warrantee. Three years later I have the same problem and the same fix is done, this time costing big time bucks. What was most irritating was the low mileage between the two replacements. The dealer pointed out that BMW warranty is for 2 years only. I asked how it it that a non-operational part goes bad? I was told the housing is a non-metal product with electrical contacts in it and it can distort from normal use. I was wondering if this is a BMW problem and if anyone out there was familiar with it. The dealer would not be surprised to see me back for a third replacement in 3 years??? :puzzled:

You may have had another warped thermostat housing, but chances are was just the gasket.
The newer gasket part is better than the old one, and chances are the fix will last longer this time
if they used the updated gasket, which they probably did.

You might want to check your radiator fan to make sure the low speed fan resistor isn't burnt out,
a common problem which could lead to a failed thermostat gasket or thermostat housing.