Ok, so I replacet the thermostat.. it was pretty easy ! but now she heats up while driving. And the rad hose off of the thermostat housing is cold. IT no open !! Or I have big vapor lock ! Now im 7 beer in and im getting too drunk and fighting with the car to burp air lock ! Its not working. I need to put the beeer down and figure out what is going on. IS it a air lock or bad thermostat from gm. Part # 12622410.

Please help !!

P.s - I don't ever drink ! Let alone drink an cobaltss.net !!

 

When you sober up, fill the car from the upper hose and coolant bottle while cold, to push out most of the air. Then run until the car reaches temp and the t-stat should open.

 

Well I did what you suggested. I took the top rad hose off and it was totally full with coolant. So I put it back on. I was still having a hard time getting the air lock out. So I took the new thermostat out and put my old one back in. The top rad hose is hot when the car is running. But the lower rad hose , which is also the one that comes off the thermostat housing is totally cold. Is it sappose to be like that ? And to top it all off the car SEEMS to run about 3-5 degrees colder then it has in the past. Even in the cold winter it ran hotter. But , when I stop , the temp rises very fast from about 90 degrees to about 95 degrees in about ten seconds. I'm not sure I have all the air out of the system. But I don't know what else to try. Any ideads or help would be great.

Thanks

 

What temp does it open at

 

You have air in the system. These cars are ment to use a vacuum bleeder for the coolant system. There's a few ways of bleeding it. One way is to leave the overflow cap off and let it idle until hot and repeat until it idle temps are normal. The other way is to pop off the little hose on the top of the engine by the intake manifold and wait for a steady stream of coolant to puss out. Only issue with that method is you have coolant in the engine already so you will get some coolant out of there in the beginning

 

It looks like you used the GM part which is great.

Also you can test the thermostat by putting in boiling water on your stove top.

It's likely air in the system. Did you drain from the water pump? Fill from overflow. Seems like most of the air gets trapped at the thermostat.

 

It seems to be ideling at about the right temp. Around 91-93 degrees. But when I drive it it seems to run a tad cooler then before. Which is wierd cause I put the old stat back in. I think the ac delco when I got was no good. I will try it in a pot of boiling water tonight just to see. When it was in my cara was hitting 106 degrees before I shut it down.

I think my resivor went down abit. It kinda looks like the drive to work might have let some of the air out. Idk , I will add more coolent and see when I get home where I am at.

I didnt drain the system at all. All I did was replace the t stat. And I'm just replacing what I lost. It just wont take much yet.

 

Just curious, if you put the old stat back in, and all is well, why did you replace the stat in the 1st place? It's also normal for a car to run a little cooler while driving. The air moving through the rad and under the car help cool off everything much better then just the cooling fan alone while it's sitting still.

 

What thermostat have you changed ? OEM GM or .......I've changed mine with OEM type from Advance Auto and I had been seeing about 178-183 degree since I put them on. When in traffic it will go up then when I get going, it dropped fast. It's worth it to me, I don't like to see at 200 degree. I know it's normal but.....

 

The way I did mine is I let engine warm up and added coolent, let car cool down and it sucks the coolent from the tank into the engine and pushes out the air, had to do that 4 times before coolent in resivour stayed at full level . Temps are right on. If u sit and wait for the coolent to get sucked into engine while it's running ull be waiting a long time cause it doesn't. That's my expirience.

 

I changed the OE GM Tstat because it started running too hot. Especially while driving. It would hit 95 degrees at times. Which is 203 degrees Fahrenheit . That's WAY TOO HOT while the car is moving down the high way at a decent speed and rpms with the heat on and fan on speed 2 or 3. And in the middle of the winter at that when it is -25 out side. And it gets up to 200+ degrees while cruising. Which is when the electric fan kicks on in low. It started doing that about 2 weeks ago. So I picked up a new T stat. And I could not get the car to stop over heating even more then it was before. So I pulled the new AC Delco out and put the OE GM one back in. ( On a side not... The two T stats do NOT even look the same. They are different heights and different diameter openings for coolant flow ) The OE GM T stat looks to be much more robust. And so here I am with a big air lock I cant seem to get out.


It seems that it works best to have the car running with the reivour cap off. Let the car warm up. And then give it gas up too about 3000rpm and hold it for a few minutes. And then from time to time giving it a few quick shots to about 3500-4000 rpm. then let the car idle normal and get out and massage the hoses as much as possible. Turn the car off. Let it cool for a bit and then repeat.

Before I left for work I did this. My lower rad hose finally had some warmth to it. After getting home it was totally cold again. But maybe it is sappose to be after a good high way drive.

The funny part is. The car is now running a bit cooler then EVER before while driving. And yet it seems to heat up fairly quickly as soon as I stop moving. Like within 20 seconds my fan kicks in.... But im still not sure I have all the air out.

 

Just to put everyone's mind at ease on temps - you aren't going to see any kind of damage until north of 260F / 127C. Absolutely nothing wrong with seeing it in the 230 range after a hard run. I would also caution against t-stats that let your car run at 175-180 - ss/tc is made to run close to 200.

 

How much pressure should be at the cap when I taken it off after it cools down abit. There is some there I can hear escaping when I loosen the cap. But not as much as I remember. Unless I remember wrong. There us only a small pshhh. When I loosen off the cap.

And frankly , how are you sappose to be able to tell when all the air is out of the system ?? Because I just tried it again with the father in law. I had him hold the car at 2500-3000 rpm for a few minutes with the cap off. Both upper and lower rad hoses got REALLY hot. And I could clearly see the coolant swirling around in the resivour. I massaged the hoses some more will he held the idle up until my hands couldn't take the heat anymore. I could feel the pump circulating through the top hose a lot. But not as much through the bottom rad hose. But then again it is much further away from the pump. The lower rad hose was really hot while doing this. Once I finished and took it for a drive. The lower rad hose was pretty cool again. But I think it is sappose to be after a drive and the coolent cools down through the rad ?

 

One last thing I just noticed this morning which I can't really figure out or explain. But when having the heater motor on. In the past, the two middle vents pushed out a lot of air. And the side two closet to the doors put out very little. Now, just sense yesterday when I changed the t stat and bleed the air out it is reversed. Now the middle vents barely let out any air ( they do some ) and the out side vents closet to the doors now push lots of air ?? Why would that all of a sudden change from changing the t stat and burping out the air ? Any ideas or thoughts about that ? And anything from any questions from my last post above this one ? Lol

 

Yeah i just noticed the temperature thing. 197-205 is very very normal on the LNF. Idling it can go much higher before the fans kick on.

So if you can get it to stay around 200 degrees F then I would stop worrying about it.

 

I have no idea about your air flow, but you might want to take a peek at your cabin filter just to be safe.

 

Yeah I'm always around 200F - 205F even at idle.

 

Where is the cabin air filter in a cobalt ?? Also , I really don't get why the air flow through the vents would change from messing with the cooling system. Its like the vents decided to which around which ones were strong and which ones where weak. Its really weird and I can't even begin to think of a way to change it back. Even if I close the two outside vents the two middle vents don't have much air flow still compared to normal. Its weird !

 

I have no idea why some of your vents are blowing while others aren't, especially side to side. The flapper only moves between face, feet and defrost as far as I know, but a clogged cabin filter will restrict airflow in general, and if you've never changed it now sure is a good time to start. The filter is behind the glove box. Lower it all the way and squeeze the back of it inward to pull the rubber stoppers through the opening, then unlatch the little string on the side. The whole unit will drop out and the filter is right in front of you. Just yank it out and push the new one in - pay attention the airflow markings on the old and new to make sure you put it in the right way. If it takes more than 5 minutes you're doing something wrong.

 

I never thought cabin filter messing around cooling system!?!?......I just don't get it.....

 

I don't getnit either. I'm not saying switchimg the Tstat caused the vents to switch around which ones flow more and which ones flow less. All I'm really saying is that all of a sudden after trying to get all the air out of the system. It just happens all of a sudden. Total coincidence?? Maybe... idk... for 2+ years the two middle vents were the string ones. Now ad of last night after trying to get*more air out. They are the weaker two now... I was like WTF ???!!! Lol

 

 

You already asked that question in another thread