I can see it happening if the t state was stuck closed because the Exhaust system has to have water to stay cool.

I will have to look into it but i think the exhaust gets a certain amount of by pass water, even when you first start the engine you should get water out of the exhaust within 30 seconds, and it takes longer then that for the T stat to open.

I'm willing to bet there is more wrong then the T stat here, and when you take it back to the dealer make sure you get plenty of documentation that states exactly what went wrong, what was done to fix it.