Howdy!
Took my IROC on it's first road trip since I've owned it this past weekend and noticed that on the highway my temp gauge is sitting at about 105 F. When I stop and idle it will get up between the half and three quarter marks but never hotter. The HVAC is blowing hot air when cruising and the temp gauge is low. I'm thinking faulty sensor? Any guidance would be appreciated.

 

Or stuck thermostat I guess maybe also?

 

Are you sure there is one in it?

 

Yep what he said
Had that before in a Monte Carlo, never would get to temp , or blow good heat. I figured t stat stuck open. Went to change it, wasn't even a stat in the housing.
But you say you are getting heat.
Might be bad gauge too, these stock gauges are well past their prime. Best we can hope is ballpark close lol

 

Yeah definitely pumping out heat. And by my calculation (google) that works out to approx. 42 C which is way too cold to be operating temperature. I was thinking maybe the temp sensor but then, theoretically, the gauge shouldn't climb when just idling. I guess I'll have to bring it in and look at it this weekend. Also noticed that after I fill the tank and drive I have a very nice stream of fuel coming out of the fuel fill. Any ideas on that?
Bought the car for 9000 and it has 70000 mi on it, it was imported from the Ohio into Alberta, and it seems like it was barely driven. Now I get to find all these little gremlins.

 

Well those gremlins can be a paint in the sack for sure. But least it's not huge. And face it , it's part of owning a 20 plus year old vehicle lol.
If were my car, I'd start by changing the stat anyhow. It's simple, cheap, and either way you will know and it won't hurt a thing to change it out.
My camaro did have a similar issue however. Took forever and a day to get to normal temp if it ever did at all.
My problem was the driver side cooling fan. It would start to run the instant the engine was started. And not turn off until engine was stopped. I don't mean when key was turned to on, but as soon as engine started the fan came on.
Turned out to be the sensor under the thermostat housing in the intake was shot. Changed it out with a ac delco sensor and now fan doesn't come on until it reaches temperature then turns off until needed.
FYI my car is 89 iroc 5.0 tpi engine and 5 speed trans

 

Thanks for all the help guys. I have to work Saturday so after work I'm going to wheel it into the shop and see if I can figure something out. Might order a t/stat and do it anyways. And BHicks you are absolutely correct... raging pain in the sack. But it's worth it when I can get more 2nd looks in my IROC than most people get in their ZL1's around here.

 

If using factory gauge, I wouldn't trust it. As I just found out, they can be WAAAAY off. I thought my motor was about to blow! Hooked up an aftermarket gauge (to the exact same sensor, with the factory gauge still hooked up), it read 180 warmed up, my factory one was reading 220-260

That, or your t-stat is missing.

 

UPDATE: Did some diagnosing today and found that on the Tech 1 it's reading the proper temp, and when I used the temp probe near the sensor on the top of the engine on my Fluke it's reading the same as the ECM, but the gauge is still way low. I am going to phone York Electronics tomorrow and see what a cluster inspection/repair will cost. Did that with my old GTA and it fixed a lot of problems.
Happy Motoring!

 

cool beanz..... the temp gauge will pop right out without having to send the entire cluster if you so choose.

 

Awesome. I was going to send the whole cluster though just for peace of mind I guess lol. But that leads me to another question. When I checked the GM service manual it said to remove the bezel, remove the 6 screws, and then pull the cluster ahead, and disconnect the speedo cable. Well I tried this and it seems like if I pull the cluster ahead I am going to break something on the speedo side of the cluster. Should I try pulling more or is there a better/safer way to remove the cluster?

 

Actually, scratch that. I just used that handy search feature and boy did I find the answer! lol