The first thermostat of seven now, blew up, and when the dealer replaced it, they put it in backward. Since then, every properly installed stat has simply stopped working. The engine doesn't get hot enough because they don't close. Any ideas out there?

 

Your engine is overheating...The T-stat is designed to "LOCK open" when it reaches overtemp. After the problem has subsided, the T-stat will remain locked open and must be replaced.

 

5 bucks says U have a 3.5 with warped heads.