I really have no idea what's going on with the wife's car, i gave her my 08 HHR LS when i upgraded to a silverado. she loves the car, but i'm starting to really hate this thing. stearing issues, airbag issues, and now, this is going to be the 4th thermostat ive had to put in the car this year alone. for the life of me i cant come up with a reason why this car is killing thermostats every couple of months. any possable suggestion would be appriciated. the last two thermostats were AC Delco's

 

The typical point of failure is the small inner gasket rolls off and jams the valve open, making the engine run too cool and causing a P0128. There are t-stats that are made without that gasket, seems to luck of the draw if you get one of them.

If the engine is over heating the t-stat is not to blame.