I just had the thermostat on my 2007 HHR replaced for the 4th time in less than a year (less than 84k miles). Thankfully they have all been covered under the powertrain warranty, but the dealer cannot figure out why they keep failing or why my car is losing coolant. They have checked and rechecked everything and cannot find anything except a failed thermostat. I had them check to see if there was a cracked head or piston liner...check the fan function & ground to the fan harness...check the oil to see if the oil level was over full to see if the coolant was possibily getting into the oil sump via the piston liner or maybe cracked piston ring...and made sure they pressure tested the colling system when the engine is both hot & cold...and i had the check to make sure there was nothing wrong with the thermostat housing to make sure there wasn't something causing the thermostat to get stuck...and they are coming up with nothing...

has anyone else had this problem with no solution...what are am I or what is the dealer missing..

 

First off, welcome to the forum!

My advice, try another dealer. Sometimes someone different looking at it may find something different.

 

There are various threads detailing the separation of the rubber on the thermostats. As for the loss of coolant??

 

i switched dealers after the second replacement because the service advisor talked to me like i was a stupid girl who doesn't know anything about cars...which i'm not...the dealer that it is at now is completed baffled...they opened a claim with chevy and there is no record of any other car having this same problem over and over..he siad they have checked everything obvious and not obvious...the dealer it is at now one that i fully trust so i know they are doing everything they can...

 

I suspect you have a cylinder head problem. Was there a trouble code each time they replaced the thermostat or was it a guess. Was it leaking coolant at the thermostat?

 

Repeated stat failures with coolant loss could be a head/ head gasket problem.
It could also be caused a clogged heater core or damaged plumbing to the heater core. Anytime the heater core is used as the pressure bypass for the water pump a clog in the heater plumbing can cause high water pressures in the block and poor waterflow.

 

there has always been a problem code for a failed thermostat...and no signs anywhere of a leak...all seals and gaskets & intakes are good and no cracks in the housing or anywhere...the last time i had them make sure there was no air left in the system because the last 2 times the dealer didn't bleed out all the air so there was an air bubble...they checked the last time and there was no signs of air and it wasn't making the gurgling noise...

 

Are they finding the rubber failed on the stat? If it is, there could be some chemical in the cooling system causing it. I've seen a vehicle that the owner mistook the coolant overflow tank for the windshield washer tank. The washer solution caused rubber in the heater valve to deteriorate in that car. Do you have the vehicle serviced at a quick lube? Many employees at these don't know what fluid goes where and selling washer fluid is very profitable.

 

i do my own oil changes & basic maintance and i promise that i've never put windshield washer fluid where the coolant goes...the dealer has found absolutely nothing wrong except the tstat failing...they have no clue as to why i'm losing coolant...so they did the only thing they could...replaced it and gave it back...they said they did every test available and even had the tech search for a reason to do an engine overhaul just to get everything cleaned out...but they're coming up empty...i'm just going to drive it around for a month and then take it to my cousin's shop and have them do a complete diag on the engine & cooling system...maybe they will find something the dealer can't...

 

What about a busted heater core? Had one go in a mustang slowly leaked into the floor. You could tell it was busted because the windsheild would sometimes get a touch foggy near the rupture.