Sharkey

iTrader: (1)

its also good to remember that in very cold weather the engine bay temps dont warm up much. the air passing through the rad doesnt heat up much, and that cold air blasting against an all aluminum engine also draw heat out of it.

ive never had a thermostat stick in my car. last winter was the coldest my car has seen, coldest i drove it in being -15*c (i know not cold for a canadian winter, but cold for a "western canada, 5 minutes north of the US border" winter). it took forever for the car to get up to 75*c (roughly 170*f), not even hot enough for the thermostat to open. on the highway the temps would drop to around 65-70*c. this is the reason commercial trucks run weatherfronts in winter, or people use cardboard to block part of the rad.

Doug's Cobalt SS SC

Sharky & Cobalts dude thanks guys this is exactly what I'm experiencing as well so @ this point I'm going to chalk it up to the cold. Also this is the 1st winter that I've had my new carbon fiber functional cooling hood so I'm sure I'm loosing some heat there as well

63 Nova SS

iTrader: (3)

Cobalt is parked unless it's an emergency. We have been below zero here since the day after Christmas. I've driven the wife's regal and my winter car a Saab 9-3 and it takes forever to warm either of them up when driving. Don't worry about your t-stat as it's all due to cold weather. Remember if the air temp is like -5 and you are driving 60 mph, that's like -40 wind chill. Nothing is gonna warm up unless you block some of the incoming air off. Unless it's just setting.

Henry3959

Your original post is not normal.

If you cannot get your late model OEM GM car to operating temp, you have an issue. Rarely have I seen the thermostat in the cobalt come out without a defective seal. That seal will not let the thermostat close completely making it near impossibly in cold weather to hit operating temps. My CTS has an operating temp of 220 and has never had an issue running there. The coldest day I can remember having it at was -20

That seal that many have posted pics of here including myself have caused the thermostat to stay just partially open to nearly all the way.

Diesels are a completely different issue as they do not run nearly as hot as a gas burner.

Slowbalt2000

iTrader: (1)

Im with HGT. Literally dealt with this this winter. 0* F is not uncommon where i live and after changing my thermostat, my car runs 196* on the highway with the heat on full blast.

Henry3959

GM manufactures and calibrates the engine to run on the cold end down to -40. In spending 2 weeks at the desert proving grounds with the Harrison division I was trained on both extremes. If you have ever unplugged the coolant sensor and noticed that it only goes down to -40, that because that is all the further engine calibrations go. Colorado has seen a low of -61F before. Fully charged lead acid batteries begin to freeze at -60F. Tires are so firm they pop off the bead when hitting a pot hole. I brought back a lot of cold weather stories when I trained in Anchorage AK for GM. When it gets that cold the techs said you just stay home, drink and (.....) with the wife.

jdbaugh1

iTrader: (1)

Are you throwing an engine code for coolant temperature below regulating temperature P0128? Your ECU will consider things like ambient temp, operating conditions, and elapsed time and set this code if it thinks the engine isn't warming up like it should. I set that code when I had a bad T-stat and it wasn't stuck open or anything but the sealing gasket was degraded to nothing. So even though my t-stat was closing the bad seal was enough to set this code. In the summer it wouldn't set it but when it was cold it would. With my new 180 deg (stock temp for my car) T-stat my car takes no time at all to get up to 170 and will stay in between 165 and 180 when it is cold out regardless of driving conditions. Summer is 175-185. If you are not setting a code I would think that means your car is determining that it isn't warming up because of the extremely cold ambient temp and that nothing may be wrong. Like people have said when you have below zero temps flowing around an aluminum engine you are going to dump some heat out regardless of what your coolant is doing. I can't offer a comparison because I don't drive my car when it is that cold.

If you are throwing PO128 I would assume the T-stat is bad. If you aren't, it could just be the extreme cold. Either way you should notice an improvement if you block to front grill opening partially or fully.

Johnny Bliss

mine takes a good 15-20 miles to hit operating temp even in 40f weather.

you also have some heat being taken out of the coolant into the oil through the oil cooler.

sounds like other people have said, thermostat isn't working correctly. not sure about like -40f but at any reasonable temp if the thermostat is working correctly it should get up to operating temp.

Doug's Cobalt SS SC

No codes being thrown however I will be sure to double check tomorrow. My guess is that it is my new T-stat because the last couple of days in Ohio have seen upper 50s & my temps are only getting up to the 140/150 on freeway after driving for 40 min & then when I get off of the freeway & into in town driving my temps are dropping to the 130 range & again this has been with upper 50% weather the past few days.

Now when I get to my house & let it idle my coolant temps will climb up to 200 & then my fans kick on like they should & my temps drop back down to around 180 like they should so the t-stat & coolant temps appear to be normal when sitting & idling however when driving they just aren't right.

Again in the past I have always gotten 5-7 years out of my T-stat & this one that is only 5 months old has worked perfectly up until a couple of weeks ago when we started getting this really cold weather so I don't know if the cold weather ruined my new t-stat or not but I'm the past that's never been the case

I spoke with ZZP & they did confirm that my t-stat from them is OEM & that it should not have went out or stuck that fast. They of course have offered to mail me a new one but I'm not worried about the $20 part it's the labor that kills me

jdbaugh1

iTrader: (1)

It's not too terrible to install if I recall correctly. Think you just have to remove the electrical box and a few hoses from the T-stat housing.

Doug's Cobalt SS SC

JD I think that's for the 2.2, the newer engines like my 05 2.0 is in the back of the engine down below the header. I have an after market 3.0" header, 3.0" down pipe & 3.0" cat back from ZZP. The header is in the way so last time I had to take my header off to go to it which was a pain

jdbaugh1

iTrader: (1)

Mine is an hybrid 06 2.2 and pretty sure the LSJ engines are setup the same because I am running an LSJ block as well as LSJ T-stat housing. Now that you say it I do remember the part of the t-stat housing that connects to the heater hose is damn close to the side of the header. In fact I had to do some slight bending to get the header to clear. I also installed the T-stat housing before I installed the header so I don't don't know for sure if you would have to remove the header to get it out or not. I've had my car up on jack stands for a week procrastinating dropping the transmission but I plan to get after it tomorrow. I will take some pictures of getting to it and put them up if you want to see what all it will take.

Doug's Cobalt SS SC

Thanks so much JD! As long as it's not going to be any trouble then yes pictures would help however please don't go out of your way to get them

jdbaugh1

iTrader: (1)

T-stat peaking through the hoses

Not sure if these will be much help but this is what is exposed by moving the electrical box. I didn't disconnect any of the coolant lines because I'm not sure I need to yet but I would think you could disconnect those and it would uncover the T-stat housing.

Doug's Cobalt SS SC

Thanks so much for the pics JD these will point me in the right direction!

user 72239

iTrader: (4)

you can replace the tstat without removing the fuse box. but its such a PITA.

jdbaugh1

iTrader: (1)

And honestly removing the fuse box is pretty easy. Unbolt and pull the top fuse panel off. Then remove single upper nut and two lower bolts which location I am pointing at in one of the pictures. Pull the harness ends out of the box and bobs your aunty.

user 72239

iTrader: (4)

yeah this summer im going to replace this one again with an AC Delco one this time and I'll be taking the fuse box off.

ECaulk

iTrader: (6)

You have to be a damn pro at that fuse box by now

user 72239

iTrader: (4)

oh dude. not even 10 minutes it comes off now.

cobaltssdude420

I didn't really read the original comments but do you have a code for the thermostat? I've got one but the temps are back to normal after the deep freeze we had

Doug's Cobalt SS SC

Hey guys it's for sure my Thermostat that's stuck wide open. What would be the best TSTAT to go with ? The one that I have in now was purchased new from ZZP & it's only 5 months old so I'm not getting that one again. Not sure if the brand they said it was OEM. I was looking at one for $39.16 on GM parts Direct part number is 12622410

Slowbalt2000

iTrader: (1)

Acdelco is going to be your best bet

Slowbalt2000

iTrader: (1)

check crateenginedepot.com

cobaltssdude420

Afaik the ZZP one is OEM according to them...