Ecotec 2.2 Thermostat Replacement?

[FFeng7]

I think the thermostat on my 2005 Cobalt had gone bad. It is taking the car a very long time to warm up about 20 minutes or so and with the heat on hi the engine coolant stays around 160. I just got this car but it can't be normal for the engine to be running this cool. My other 2007 Cobalt warms up fast and stays around 190 regardless of where the heater is set. What do you guys think? Should I put a new thermostat in it first? Any recommendation on brand of thermostat? Thanks in advance guys.

 

[eljefino]

Sure sounds like the thermostat! Are you getting the temp from a scan gauge?

OE is a good place to get the buggers, there are a lot of nasty ones out there. Stant from advance/ NAPA is a safe (not sure) bet.

 

[Kruse]

This is one area that I would get the replacement from the dealer. If you car was an old beater or your second car, your higher-priced replacements, like a Stant, would be fine. But there is almost no worse feeling in the world than to replace a part, especially a hard to access thermostat, and then realize that the new one does not work.

 

[SaturnIonVue]

Originally Posted By: eljefino
OE is a good place to get the buggers, there are a lot of nasty ones out there. Stant from advance/ NAPA is a safe (not sure) bet.

What eljefino said. OE would be your best choice, even if it costs more. It's also more likely that you would get the correct one for your application, and not risk getting a junk aftermarket part.

 

[ABerns]

Agreed, sounds like the stat. An easy and cheap first thing to replace at least.

And I second the recommendation of buying OE. While I've never had a bad experience with aftermarket stats, I've heard stories of those who have. Well, not "horror" stories, but thermostats failing quickly. While it's not a terrible job, it's not one I want to do every 30k miles...

 

[FFeng7]

No I don't have a scan gauge but there is a digital temp readout in the instrument cluster. I am probably going to get the stant from Advance Auto Parts. I'm was thinking that if could also be the temp gauge sending unit but I'm going to try the thermostat first. After doing some research online seems to be a common occurrence on Cobalts. The rubber seal on the thermostat deforms and causes it not to seal. I hope to swap it out on Monday so I should know then. Coolant looks good in the car So I may just top it back off with fresh Dex Cool instead of flushing the cooling system after changing the thermostat.

 

[FFeng7]

Oh well I may have to give the dealer a call to see what the price on a OE thermostat would be.

 

[eljefino]

From a cold start if the dash temp is within a degree or three of ambient the sensor should be good. I was asking about "computer temp" vs "gauge temp" as gauges are notoriously awful.

They say the ecotec is an evolution of the saturn 1.9 16 valve and if they used a similar thermostat it will run cool with wear.

 

[FFeng7]

Good point I will have to see what the gauge says tomorrow. That's a great idea to compare it to the ambient.

 

[FFeng7]

Ok upon further online investigation it looks like replacing the thermostat on a 2005 2.2 is a real pain. It's located behind the engine in between the engine and exhaust manifold. Has anyone ever replaced one of these? It also seems that on newer models that it is located on the side of the engine and a little easier to access. I'm going to try it myself but just wondering if anyone had any tips?

 

[MinamiKotaro]

If you remove the upper and lower heat shields, it's actually pretty easy to get at the thermostat. You may as well plan on replacing your coolant, because you're going to lose it all.

 

[FFeng7]

Thanks that's good to hear! Is it easier from the engine compartment or from under the car?

 

[MinamiKotaro]

Originally Posted By: FFeng7
Thanks that's good to hear! Is it easier from the engine compartment or from under the car?


I think I had to get some bolts out from the bottom and the rest from the top. It was pretty easy to get the pipe out from the bottom, though the internet informed me that would be impossible and I absolutely had to take it out from the top.

 

[FFeng7]

Thanks MinamiKotaro I'm going to try and fix this car tomorrow. Unfortunately, against the advice I got here I'm going to use the stant thermostat. I hope that is not a mistake and I'll be doing it again in six months. I'm also planning on doing a oil change, transmission fluid change and tire rotation. So I will post back here tomorrow and let you guys know how it goes. Thanks again everybody.

 

[FFeng7]

Ok I did it I changed the thermostat. It wasn't too bad but it did take about two hours. Had to remove the heat shields around the exhaust manifold. Than I could access the thermostat from under the car. I also drained the block, heater core and radiator and refilled with fresh dexcool. The old thermostat had the rubber seal distorted and that was causing the coolant to bypass the thermostat. I also changed the oil with shell synthetic 5w30 and a purolator classic filter. Changed the transmission with fresh Maxlife ATF and rotated the tires. All in all a great day doing some vehicle maintained.