sleeper

Would advise caution doing the anti-freeze & T-stat. The Engine is higher than the radiator, because it is critical to get all the air out or it can get trapped in the higher elevation head & cause bad problems.
But it can be done, just making note of the issue to be careful of. Many will park their ride uphill so the front is higher than the rear, to help the air to go to highest level.

donbrew

Somebody may have installed a 190F t-stat. We have heard of GM parts books insisting on it and some old farts refuse to learn new stuff.

Get the GM 12622410/ ACDelco 131-158 ONLY DO NOT CHEAP OUT ON THIS PART.

The t-stats job is to keep the temp ABOVE the rated temp. The computer turns the fan off when the temp gets back below 180F. The SS has an infinitely variable speed fan, so it is a bit different from the other models.

Cat Man HHR

I have watched my temps when I first got it on very cold days. It would dance between maybe 195 to 209, maybe 215, when idling. Now owning the car for a few years this is normal. Mine is 2010 SS with 55K and never had an overheat/cooling problem.
Don't worry, be happy.

DrLoch

Here is the Fan Desired % vs ECT in an SS

firemangeorge

DrLoch
So, I read this as the cooling fan will 1st come on when it hits 199.4 degrees F. ?

donbrew

Yes, at a 15% duty cycle.

firemangeorge

Thanks Don. Was just wanting to clarify. I wasn't sure of the exact temp so now I'll know.

Find it odd that the % increases at temps with different "point whatever" degrees. I guess some of the GM programmers had a little fun when they set that up.
They seem to have got them all. "point" 0,1,2,3,4,5,6,7,8,9 are all there.

donbrew

Duty cycle thing get weird. There is no 100% because of the internal resistance so 95% becomes 100%. Actually the duty cycle is a continuous function, it is not a table. So those numbers are probably what some guy read in real time and wrote down, or approximated.

DrLoch

That table is what was read from the ECM how the exact number are derived is somewhat of a mystery in some cases. Don't know if it a rounding... the file is translated from HEX numbers so it could be just that. Sometimes even when you make a change and save it the number is not exact. Not really given it much thought. But Don is correct in both cases. @199 the Fan starts running @ 15%, it's what's know as a PWM or Pulse Width Modulated Signal. More efficient

firemangeorge

Interesting.
Mine hardly ever reaches 199. Only time I'll see that is summer time and stuck in traffic. Don't think I've seen 199 in several years, BUT, the fan is usually on when I get home and park it in the garage. (no AC or defrost in use )
Go figure.