To save the coolant. Plus, if you don't drain it, you'll make a big mess when you pop the cover off.

i agree don't drain the coolant it will only lose about 1/2 of a gallon. I just did mine the inner gasket had broken and was lodged in the opening keeping it partly open
http://img208.imageshack.us/img208/5...stat007.th.jpg
http://img232.imageshack.us/img232/5...stat006.th.jpg

There are right ways, and wrong ways of doing things. To not drain the coolant properly is definitely the wrong way. Losing a half gallon on coolant on the ground and all over the engine (to smell for the next day or two of driving) is a sign of mechanical incompetance, to say nothing of a total disregard for environmental issues.

Here puppy, lick this mess up.

Jeesh.

Mine just did this this morning. Already had an appointment to get the oil changed before the Tail if the Dragon cruise. Called and told them to look at this too. On the way home from work however the temp gauge and dic started to register again. Must have came unstuck. Still going to have them fix it. I might as well get everything I can out of my 100,000 mile warranty

I changed mine yesterday,cleared the code at Advance Auto, $183 saved!

I just did mine yesterday at 73K+. It had thrown a code for not getting up temp properly, and having read about this earlier, I went right for it. My old one was just like max69power's above - the inner gasket was stuck in the valve, so it never completely closed.

Access is not good on the SS, and it took me a couple of hours, which I mostly spent trying to find a dropped bolt and a dropped 10mm socket on different occasions. I accessed the upper bolt from above and the lower one from below the car, and that seemed to be pretty straight-forward. After refilling, I had a bit of a bubble in there and it almost overheated at first, but after leaving it to cool for a couple of hours it had pulled in all the coolant from the reservoir. I did that cycle one more time, and all seems well now. The CEL is off, engine temps are normal, I have heat, etc. My total bill was around $50.

Tip: to clear that code, you can disconnect the battery for a few minutes (and it won't affect the radio settings etc.), OR just drive it a few times and the code will clear after a few drive cycles. :)

Just changed out the thermostat on the kids' HHR this morning after sporadically getting the P0128 code over the last several weeks. Thanks to you guys, it was real easy, even for a software engineer!

So, why do you have to drain the coolant? I changed my thermostat a while ago and I didn't drain the radiator as described and only lost a cup full. Is it just an environmental thing or a mechanical thing? Curious because I have to do it again tomorrow!

It's just good practice, however Dexcool is good for150,000 miles. But for the environment, you should "capture and dispose" of the leakage.

Changed my thermostat today. Pretty easy really. The second rubber seal had come loose and was restricting movement of the thermostat. Problem solved!

I've changed my thermostat but its still running in the lower 170's to 168 and eventually flat lines the temp gauge and cuts off the A/C.

When installing the thermostat, does it just sit on top of the housing, or do you have to wedge it down into some grove???

Also, I've done this before when I first got the car, and replaced the temperature sensor. I'm at my wits end.

Howdy Franksb255 - check post # 10 in this thread by Biker Ken - he had the same situation where the temp would not rise to normal operating temps after changing the thermostat - and he had to BURP the system - the post gives all the details.

I can't remember how the thermostat sits in there, but I expect there would be no special trick to it all.

whopper. Thanks for the reply. I'm going to BURP the system when I get off work. I thought I did a good job refilling the coolant, letting the engine idle for a while and trying to get as much in as possible.

Reading up on Burping, it seems to take a long while, and I also read a good note of jacking the front end up some.

Hopefully this works, otherwise I'm considering replacing the temperature sensor again.

Last night I even thought maybe I had to much water in the water/dex cool ratio, so I drained out as much would come out of the petcok and then refilled with straight dex cool, not 50/50. Still running in the 170s.

There was a post a while back about trash stuck in a new thermostat. Seems the owner changed their thermostat. The new one wouldn't let the engine heat up. They took it back out and found a piece of the old thermostat rubber seal wedged in the new thermostat. That "trash" just kept the new thermostat wedged in the open position and wouldn't allow the engine to heat up properly.
Just something you may want to consider.

Good memory there firemangeorge.

Naw, the mixture being off would not make a change to the temperature like what you are experiencing.

This may help to test the sensor if you have an OHM meter: http://www.doityourself.com/stry/how...r#.UgQEeX9rYv0

I don't know what the actual resistance one should be seeing on the temp sensors the HHRS use. would be handy to have that info posted here.

Running more than 50/50 DexCool is dangerous!

The new t-stat should have a rubber gasket around the outside, that fits snugly into the t-stat housing then the t-stat cover goes over it. If you are missing that gasket or got it twisted it will cause a problem. If missing you will probably have a puddle under the car.

I'll try to see if Mitchell has a spec.

I can't seem to find any specs on the ECT. It is probably a thermocouple device, which would put out a voltage in the mV range. Resistance is futile.

Okay. News. Got a new temperature sensor at Oreilys. Didn't drain the coolant anywhere before replacing the sensor, so I lost about 1/2 -1 quart of coolant. New sensor in, a little dex cool straight into the coolant fill port. Made sure my coolant extra tank was filled to the cool line.

Crank it up and it reaches temperature rather quickly. Drive around the block and it's running at 185 degrees. I'm not touching it anymore and we'll see how it does on the 20 mile drive to work in the morning.

No burping, just pretty sure I had a funked temperature sensor.

Also, I'm pretty sure I installed the thermostat correctly, it seemed a very simple in and out procedure, I was just at my wits end and was thinking maybe I did it wrong and coolant was slipping past the sides of the thermostat or something.

ahhh cool (no pun intended - ok, maybe it was). Keep us posted with an update after a few days.

I will say it again. Full strength DexCool is a very bad thing, it tends to gum things up.

C'mon, no one? Gotta be a Dr. Who fan somewhere.:corny:

At least we didn't have someone jumping in and advising to drill holes in the thermostat on this one!!!

Drive to work went great today. Running at 181-190 degrees.

Thanks to Smoke Wagon and others who posted about how easy this is. Unlike most of you, I do not like cars and hate car engineers.

Even I was able to do this and it fixed my a/c problem as well! I love twofers!

I didn't read through all of these posts...but, let me just say that the SS thermostat is a pain in the a$$ to do...I have big hands and arms and changed out my thermostat today...all went well(with some time consumed working around wire harnesses and the high pressure pump) with the exception of the CEL...anyhow there is a lot of stuff in the way to do this on the SS...was almost a 2 hour job with all the crap I had to work around...

Right after the cooling system had some air in it...but, all is well now...195-205

Don, "resistance is futile" was from Star Trek Next Generation, to resist assimilation with the Borg, but it could have been taken from Dr. Who

Those tin cans with toilet plungers went around saying "resistance is Few-Tile".

It took almost 4 months for anybody to notice.

Thanks for the info and the pics. At first I thought I had the wrong place identified!

Great thread.....with 36K on the odometer our's still has the dreaded Dex-cool and maybe we should do a thorough flush and use something else before troubles arise. Appreciate seeing everyone's input!

WHY ????? Your vehicle was made for DexCool and came with Dexcool. Everyone, except a few, here uses Dexcool.

You're probably worried about the Dexcool and problems of 10 years ago. Not the same conditions, product or vehicles. Don't worry about it unless you have a transient leak which causes problems and keep it topped off.

Oh, and it has been talked about frequently on this forum. If you use the Search field you'll find many posts with references and discussion.

"DREADED"?????? You mean like "has dreadlocks"?

DexCool has a 5 year lifespan, which is longer than most of the others.

Where in this "Great thread" did you find a criticism of DexCool making you think you should change it to something else?

DexCool* is not a problem, lack of maintenance at correct specified intervals IS..

dex used to attack plastic and rubber, mostly in gaskets and hoses.
sadly, its a lack of trust for me.
anyone who leaves coolant of any kind in their system for more than 4 years is bound to wind up with problems, regardless of brand.
For me, I chose not to trust dex for more than 18 months. Its in my 09 SS and is new(new flush in 3/14) but it will be out when I hit 60k

"lack of maintenance" will cause more damage to components than any product on the market.

So grateful for this forum sometimes. I just got this issue yesterday and had it fixed in no time today. Thank you Op for the great instructions and everyone for the feedback. Saved me a ton of time and money

IDK bout the aftermarket t-stats. Got one at Autozone, failed within 4 months. This time I got the GM dealer t-stat. Double the price @ 50 bucks and we will see how long it lasts. Definitely looks a tad better built and made in Mexico where my car was made, lol.

Just today while debating a exhaust manifold gasket job I spied a puddle of DexCool on the transmission below the t-stat housing. I decided that was an invitation to forget the gasket job, so I pulled the t-stat out and found that the large rubber gasket (the one that is detachable) was not secured to the t-stat. I know that it was at one time,

Anyway reinstalled it with a new gasket.