My coolant temp has been swinging worse than Mick Jagger in the 1970s.

I'm at 188. Seconds later, 207. Back to 190. I do know that it's created by motion, and an answer I found elsewhere told me at 220, a fan kicks in to help.

But I don't like the heebldee jeebldees. Highest I got was yesterday - 216. Normally in the 190s. Never over 216, never below 185.

My questions:

1) I have DexCool 5050 in my HHR. Can I use full strength? Would that run a cooler temperature?
2) Do I just maybe have dead coolant? Last flush and fill 18 months ago, maybe two years.
3) 144,000 miles. That has nothing to do with it. Or does it?
4) What's the "death temp" for coolant? I read 240 from a mechanic on Quora - credible?

I'm in Dallas. It gets hot. But when I was younger, I stupidly melted a head gasket and the whole head on two different cars. Would love to throw ice in my HHR and keep it COLD, COLD, COLD, and damn fuel efficiency.

 

Temps seem normal for a hot climate...



On the dexcool mixture... Use as specified (50/50) Stronger coolant mixtures don't mean cooler temps. Sometimes the opposite occurs, and this goes for all types of coolant, not just dexcool...


I think the fan kicks on at 218* if I recall correctly.

 

Dexcool has a 5 year shelf life. You might be low on coolant, check under the pressure cap. Otherwise that temp range is not a problem. 240F is getting to death.

 

Yes, temps seem normal if... that higher reading is when you are stuck in traffic, at a red light or idling for an extended time. There is no air flow thru the radiator when the car isn't moving. Thus the radiator doesn't have the air flow over it to cool down the hot coolant.
Now if it gets hot enough for the fan to come on, then it will cool it down even when the car isn't moving.

I'm guessing that you've never changed the thermostat ? You may want to do that also. But remember, only use a genuine AC Delco stat. Some of the other brands have been noted to not work well in the HHR's.

 

Answer

#1 Dex Cool is 50/50 ? It should be from the container. Straight water is the best for cooling an engine. Using straight anti-freeze is not a good idea.
#2 Bad coolant can coat coolant sensors causing bad readings. 18 months from a fluid change, I don't see a problem.
#3 You already did an anti-freeze change. Yes it should have been done every 5 years or 50K miles.
#4 Yes 240*F would cook the engine. Along with that, coolant would be pushing out the radiator .

Temperature bouncing back and forth makes me think you have air in the system.
Question ? Did you know if you have the original thermostat in it ?

 

If the temp gets higher than you are comfortable with in traffic, just put the AC on in order to get the electric fan on. Should cool it right down.

 

Fan should go on regardless when the temperature threshold is at it's rated temperatures.
So your in 100*F temps with the AC on and the engine doesn't cool down. Now what ?

 

He is right - it has been asked a billion times - well, may not quite a billion - more like a million.

- The temperatures and the temp swing are well with-in specs - that's the way it is designed
- the coolant was changed well within the 5 year life span of the Dexcool

Just make sure the coolant level is kept at the right level, and quit obsessing over the digital temp gauge. As others have stated - the swings you see are WELL within specs.

If you are trying to cool it below the way it is currently operating, don't do it - you will just throw a lot of the calibrations of the engine out of wack, and will only generate a poor running engine.

 

You could give baby a burp...

https://www.chevyhhr.net/forums/how-...-system-60614/

that’s a good HHR