Hello,
I have an 86 Iroc, 305 TPI with 30k original miles. I need any ones help or input with this mystery temp problem. I thought the car was running hot, but in reality it isn`t. The temp gauge was reading 250 ( which is really overheating). I had a buddy hook it to diagnostic machine, the machine says the car is running at 220, the gauge says 250? I put a brand new gauge and coolant temp sensor in it. STILL doing it? The electric fan kicks on at 226 degrees and back off at 211, per the machine. But the gauge is reading 245 to 250? Anybody have this happen to them? Any advice would be greatly appreciated. Antifreeze is good, thermostat is a 195, I just want the gauge to display the actual engine temp, is it a bad ground or something?

 

you gauge it self might be bad cause i kno the chevy trucks go bad. stick a manual gauge in it and try that.

 

Thanks for your advice about the manual gauge, but I don`t want to change from factory equipment. I would rather troubleshoot than change from original. To all other responses, I can`t open private messages on my computer for some reason, and new to site, I would appreciate it if you could post your messages again publicly so I can view them? I value anyones input in my temperature problem. Thanks.

 

Yes that sort of thing happens all the time.

You don't have a

You have a gauge problem.

Don't worry about the "temp"; worry about the gauge.

You day you replaced the "coolant temp sensor". That term is usually used to refer to the sensor in the intake manifold whose sole task is to tell the ECM what the coolant temp is. It is not connected to the temp gauge reading in any manner way shape or form. If in fact that's what you changed out, you replaced the wrong thing. Try replacing the temp gauge sending unit, which is the thing that works the gauge; it's in the driver's side head, between the #1 & #3 plugs.

 

Hey,

Thanks for that advice, I appreciate it very much. I just text my mechanic your message. We weren't aware of the gauge sending unit? At work now, but gonna check it out when I get home. I will keep u posted if it works , which I believe it will. Brand new gauge, new coolant temp sensor , and cleaning all contacts relating to temp didn't work, lol! I think this will if we can locate it .

 

lol! we did replace the sensor between 1+3 cylinder that controls the gage. However, mechanic says we might not be getting good connection with the wire that's plug into it? very loose on the single prong. Some body else suggested replacing coolant sensor near thermostat for ecm not gage? Don`t know if I should?

 

You can replace the connector with a regular spade connector. The sensor by the thermostat has nothing to do with the gage as said before.

 

Thanks Joe, I will probably try that, because its really loose on there, might be just bad connection?

 

I bought a OEM temp gauge from franzen chevy. solved my problem . if you need their number PM me

 

Hey thanks, I just sold the car on Wednesday, the new owner knows the issue with the gauge problem. I will pass it on top him, thank you, and all for your advice and input, much appreciated!!

 

you SOLD it!!?? may all your children be born naked!!

 

does anyone have the part number for the temp sensor that communicates with the ecm?

 

I had my temp gauge go bad on my 89 iroc (350TPI) years ago in the early 90s when the car only had 60,000 miles or so. I pulled the cluster out and changed the gauge and all the bulbs while I had it out and it worked great from then on.