My 2008 Chevy HHR has gone through three thermostats in as many years. Replacing the thermostat as fixed my AC problems but I need to find out why the thermostat has been failing and I don't want to go through the expense and extended time to take it to the dealer. I'm trying to find out what type of mechanic shops can handle the diagnosis and repair without costing me an arm and a leg. I'm in Clearwater Florida.
Any suggestions?

 

T-stats fail because the inner rubber seal dislodges and jams the valve open. The ONLY PART THAT SHOULD BE USED IS ACDELCO 131-158; not "like","replaces" etc. Not even the one a GM parts guy will hand you if you just ask for "a t-stat for my HHR", that will be the cheap one.

The ACDelco 131-158 will cost something like $49-$60, but should last forever. Installation is a matter of 2 bolts and 1 skinned knuckle, no coolant draining needed.

Dexcool has a life of 5 years, regardless of mileage.

T-stays do not cause overheating. T-stats are not maintenance replacement parts.

Normal operating temp is about 190F. Under 180F will inhibit the AC and cause a CEL. If the temp gets up to about 219F the fan will turn on the off when the temp is down to 180F. IOf the AC compressor is running the fan should be on.

 

https://www.chevyhhr.net/forums/prob...i-think-57893/

In post #5 you’ll see a photo of a failed thermostat. Trust me when I say get the thermostat Donbrew mentioned, I’ve tested several brands, I now only use the correct thermostat, it warms up to temperature in the parameters the ECM is programmed for.

 

Original question asked about “anyone besides the dealership ?”
Guess you mean a Chevy dealership ? Honestly not sure why you would consider those. It’s a 16 year old car. Most of those techs at dealerships haven’t seen many HHR’s much less worked on them. Find an independent or national car repair shop. There must be lots of them in the Clearwater area.

 

I changed my own t-stat a while back, wasn't too bad (except for the skinned knuckle) I first put in a cheap t-stat, then after reading here, got the more expensive longer lasting one and changed it out. never regretted it. should have used the right one to begin with.

P.S. I did fight a bit about it being the temp sending unit, but I was wrong. listen to these guys! they know what they are talking about!!

 

Since my last post I have replaced the thermostat with the correct AC Delco part and like all the other times I replaced the thermostat it's solved my AC blowing warm issue. The AC continues to blow cold until I stop using it for the couple of cool months of the winter but when it starts getting hot again and I go to use my AC blows warm again this has happened for the last five years in a row and I can't figure it out and neither can any of the mechanics I've taken it to. ANY IDEAS?

 

Air trapped in the cooling system, old Dexcool or incorrect mixture, has to be 50/50 Dexcool and potable water. Some like it a little stronger, but that’s not really necessary.

 

There is no other part number ACDelco 131-158 ONLY. A GM dealer will sell you the cheap one unless you Specify ACD 131-158.
Any Check Engine Light? What is the digital temperature? Are all of the settings correct; air flow not recirc, temp set to full blue, level set to upper etc.
DexCool has a 5 year shelf life. You might replace the temp sending unit?

The digital temp should get up to 180F in less than 5 minutes and stay above 180F while running.