Hi , were new to the site and im after a second opinion really. I think im right in my diagnosis but i just want to double check so i dont look a fool when i take it back to the dealer if im completely wrong. We got the car from an independant and got 3 months free warranty. The car is a 2003 mini cooper with aircon and 50k miles. Basically after a 90 mile trip we parked the car up last night and all was well. Came out to it this morning and there was a puddle about 7 inches across under the front bumper that smelt like coolant/radiator. It was to the left hand side of the car and the under tray and lip under the bumper was wet. I think theres a slight leak on the rad but wasnt sure if it could be the thermostat housing seal? Ps the car was running at the right temp and there has only been minimal coolant loss, if any at all. Thanks

As you say could be radiator, thermostat housing or just a hose leaking. The bottom corners of the rad and thermostat are both common leak points and the replacement parts are supposed to be improved.

Thanks for the reply. Am i right in thinking the thermostat housing is on the right hand side of the block? If it is leaking wouldnt the coolant drip to the floor more to the passenger side of the car? As i look through the front mesh in the lower bumper it looks damp under the rad. Obviously with all the rain weve had its difficult to decifer between the coolant or rain water against the black trim. I havent had time to take off the under tray to have a look unfortunately

Yes, thermostat housing is on right under the yellow coolant filler/pressure cap:
Diagram:
RealOEM.com BMW R50 Cooper Waterpump - Thermostat (http://www.realoem.com/bmw/showparts.do?model=RC32&mospid=48010&btnr=11_3099&hg=11&fg=35)