Had my Monte (03 SS) almost 3 years. When I bought it, it had a failed thermostat - stuck open. I replaced that. Today I am installing the 3rd replacement thermostat. 1 a year. All failed the same way - stuck open. Anybody have similar prob? Any ideas as to causal gremlin(s)?

 

Have you had your coolant flushed? Perhaps the dexcool has started to break down and get sludgy, which is sticking to the thermostats??

 

Any other odd conditions (such as does it start running hot before it fails, pehaps an abnormal temp is damaging the properties of the T-stat material). Other thought would be get a different brand t-stat, see if that makes any difference.

 

Ya. Had system flushed by a radiator shop last winter. Dexcool all gone. Have green coolant now.

 

Did get kinda hot once last summer. Hmmmm. Thanks guys.