MikeRuth

Good day all.I have a pretty stock 2006 that has been pretty good except for the typical chattering breake syndrome.
But today I noticed the CEL on and I had just started it up and got on the freeway in less than 5 minuets time. As I was cruising down the road I noticed the coolant temp low 160 to 165, it never really did come up to temp on a 20 minuet freeway drive. Everything else seemed ok.

So I'm guessing maybe a T-Stat but I am going to let it cool, see if I need coolant or not, No signs of leaks anywhere. and I have pulled the fuse on the batt to reset it and see what happens. I'm also going to recehk all the fuses while the batt is disconnected.

Oh and it was a cool morning, about 60ish outside and slightly damp. I had turned on the heater and it felt as hot as it ever has, so I didn't think that I had a low coolant problem.

Any comments or ideas are most welcome.

ChevyMgr

Thermostat.

MikeRuth

I tend to agree with you.
Update. Cooled the engine and checked the coolant level. 1/3 full in tank, full under pressure cap. With the battery disconnected checked all fuses and relays. REconnected the battery, changed the oil and filter, fired it up. No CEL and temp was rising fairly well.
warmed up for three minuets and then hit the same freeway for about 5 minuets, 172 peak on the freeway, short stop and go upto 178. Parked for 10 mnuets, 181 when restarted and drove home over surface streets, Temp maxed at 182 with an outside temp of 65. Tjhis was over two long uphills and both had brakes on(chattering after no. 2) with a stop at the bottom of each. Broke 190 upon arriving home. I'll keep an eye on it, and pick up a T-Stat.

Now to deal with the typical passenger side water leak.

Goose2448

I had this problem only it that the temp shot all the way up on the guage. Though if it is reading correctly, I would not worry about it. I have a 160 tstat in my truck and it runs at around 140 on 110 deg days rolling down the highway at 80, 3000 rpm. As long as it does not go up too high your fine.

whopper

One semi-common issue with the thermostat, is that it uses a gasket on the movable part of the thermostat valve - and that gasket can deteriorate and jam the valve in the OPEN position. If that happens, the engine is slow to warm up - or if real bad, may not come up to the proper operating temperature.

Here is a link to the procedure to replace the thermostat - https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/

and this thread details the many symptoms that can pop up when the thermostat fails: https://www.chevyhhr.net/forums/problems-service-repairs-42/help-please-electrical-gremlins-invade-elvis-31746/

Don06

I posted in another thread that my 2006 with the original thermostat driving 50 mph on a 45 degree morning goes up to 192 degrees then might drop to 189 for a few seconds before going back up to 192. The thermostat is in there to keep the engine at the optimum temperature to get complete combustion. The computer adjusts fuel parameters and transmission shift points to compensate for a cold engine. If the engine temperature is low it can effect fuel consumption and driveability.

LawDog88

Hey all. Had problems with my t-stat going funky. Dropped to 158. Looked this up on the side of the road. Saw that coolant level coul be it. Sure enough it's down about 6" from the full mark. Next stop is for some antifreeze.

sleeper

The HHR overflow jug full mark is way lower than 6 inches ..