Hey everyone! I’m new to the forum and a new owner of a 2009 HHR SS 5spd for two months now. Love everything about the car, but it’s mysteriously overheating. One day it runs normal, and other days it’s overheating. We’re talking 260 degrees hot. What confuses me is that it’s running like nothing’s wrong at that temp. The only thing I’ve noticed when the car starts to overheat at that temp is the heater blows cold air. When the heater is working, the coolant is 189-190’s range.

The car has 42,000 miles. Head gaskets were replaced before I purchased it. CEL is always intermittent.. one day it’s on, most of the time stays off. The car is getting worked on Monday morning (under warranty).

The error codes for the engine light was exhaust/intake cam shaft position timing - over advanced bank 1, and the other code was cylinder 1 misfire. The dealership is suspecting a bad thermostat, but I feel like more is going on.

Any input will be appreciated. Thanks in advance guys.

 

Welcome to the site, Have your local parts palace pull the codes, write them down, post them here.

 

P0011 intake camshaft position timing
P0014 exhaust camshaft position timing
P0301 cylinder 1 misfire

 

These turbocharged direct injection engines have a problem with carbon build up. Usually on the intake valves, but could be inside the combustion chamber also. On the valves could be your misfire. In the combustion chamber could be your overheating.

I would be performing a compression test and putting a camera through the spark plug holes to inspect the combustion chambers.

Overheating could be caused by other issues, very, very rarely is the thermostat to blame. It would have to fail in a closed position, but that's not how they fail. They fail open, causing the engine to run too cool.

We're figuring that the coolant is full and in good condition.

Another potential cause could be a fouled(from the same source as the valves and combustion chambers) intercooler.

 

T-stats don't cause OVER heating normally. I would steer clear of that shop; you have no need to go to a dealership except for recall work.

If the timing chain has recently been changed there is a good chance it was installed a bit off. Or, you need to replace both VVT valves. For overheating and the P0011/P0014, possibly the P0301.

Could be a clogged heater core. Could be a bad radiator fan or controller. The fan should come on at around 219F or when the AC compressor is on.

DO NOT drive the car at over 250F Park it immediately. Death is imminent.

 

Welcome
If the car has been up to 260 degrees, then damage has probably occurred. The question is, Why was the head gasket replaced before ? At that low of mileage.
I'll bet it was run hot before, someone replaced the head gasket, but never fixed the cause of the running hot issue.
No offense, but this car sounds like it's going to be an on going problem. You should consider returning it and finding another.

 

May I suggest burping the coolant an air bubble could be the overheating issue.
the VVT solenoids will be the P0011, P0014 issue.

https://www.obd-codes.com/p0011

https://www.obd-codes.com/p0014

 

Oh, I somehow missed the head gasket! Wasn't 2009 the porosity issue? Also explains chain off a link.

 

This could explain it all. Air bubbles can do those kinds of things and really affect anything. Put the front end on ramps. Remove the radiator cap. Let it idle till the t-stat opens. Top off any time the coolant level drops. It will eventually expand and overflow. Nose up gets the air out with these cars quite well..

 

Tried 3x to delete the multiple. Sorry, the site's unresponsive.