When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Problems/Service/RepairsIf you have a problem with your HHR, want a tip on repairing or performing a particular service to you HHR here is the place to post!
Isn't it possible that very low ambient temperatures combined with very small load on the engine could cause the coolant temperature to dip below 180 temporarily, thereby closing the thermostat, then the coolant temperature rises again, opening the thermostat, rinse, repeat.
Pennsylvania isn't that cold. We have another member in really cold weather says he is getting to 199F. I have seen the fan cool it down to 179F for a second or 2. When my t-stat stuck open it ran at 175F on the highway in 20 degree weather.
Sorry, I keep forgetting to come back here, but I installed the new thermostat a while ago, and the middle seal of the old one was bad. The new thermostat doesn't seem to have a seal in the middle, so I guess they updated it? (or maybe I didn't notice it). Temperature is staying above 180 now, it has been working great since. The coolant was perfectly fine, and it was bright orange. I'm still having issues with oil missing, but I'll start a new thread since this title is misleading. Thanks for noticing the thermostat, I wouldn't have noticed it probably until it went even lower in temp.
Dexcool has a shelf life of 5 years, doesn't matter how bright the color is. It wears out in time not hours of use or miles driven. Overheating destroys it.
I just took that hose off to clean the throttle body a few weeks ago, and I didn't really notice anything. I'll check again though. The dexcool I have in there is only 1-2 years old, and I added new instead of reusing what I drained out. What was in there before the timing chain service was definitely older than 5 years though, so thanks for letting me know.
I checked the oil today and noticed that I was low on oil again, either 1 quart or more than one quart. Not sure why, but the side of the dipstick with the notches reads higher than the backside on a level surface.
There is sludge on the oil cap. I've always seen it there even before I did the timing chains, there was some built-up under the valve cover too. It's yellow and usually has water around it, so I assumed it was just from driving such short distances (only around 5-minute drives usually).
That sludge in the oil is surely oil/water emulsion. When the engine is cold, water vapor, one of the products of combustion, condenses before it escapes a cold motor, and your problem with thermostat would surely make it worse, and Winter makes it worser. If you only make short trips, that condensate is going to accumulate and form an emulsion with the oil.
You could add a little Seafoam to the oil, drive it easy for a couple hundred miles (not short trips,) and change the oil. After that, for every several short trips, try to make sure the car gets one somewhat longer trip that gets the motor to full operating temperature. That should flash off any condensate, even from any emulsion, turning it back to just oil.
If you still get sludge in the oil, there is a coolant-to-oil path, maybe a bad head gasket.
Last edited by PulpFriction; Mar 18, 2022 at 02:43 AM.
