Hey guys, i got an 86 iroc-z28 with 65K original miles. When i drive in the city with stop and go traffic the temp gauge climbs right up to underneath red and sometimes in the red. On the freeway doin 65 it doesnt do that. The previous owner said he changed the thermastat so I thought maybe since its an aftermarket one its giving problems so I went to a chevy dealer and bought a new original thermostat. Should this fix the problem and how hard is it to replace the thermostat on an iroc with that intake covering the block?

 

I would investigate the fan before tearing anything apart. Seems like if your temp is normal on the freeway, the coolant must be flowing through the radiator. If it's hot when you're standing still, the fan may not be pulling air through the radiator like it should.

Based on my own personal experience, I would almost change the temperature sender out before the thermostat. I found out mine was bad. It was giving me all kinds of weird temperature readings.

 

Do you have a mechanical or electric fan? I assume it's the latter. Is it functioning as designed? Do you have the air dam in place?

JamesC

 

ok, just noticed that the fan doesnt come in. At all. Temp goes down when im driving and goes up in stop and go traffic or stand still

 

James, don't forget that with the airdam you gain airflow with higher speeds and he said he can do 65 MPH with no problems
You made some good points that I will address

 

Well, you just found your problem

Lack of Airflow causes in City overheating
Lack of Coolant flow causes Highway overheating

Tell your friends

 

JamesC,
Sorry i didn't get a chance to explain myself when I wanted modify your ideas

I'm just trying to help all the members

 

Obviously the fan but just to throw something in there, I removed my thermostat and hooked up a new mechanical temp sender to help figure out the problem I had overheating.

With the thermostat out, if it still overheats then thats not your problem and a mechanical temp sender was a lot easier to install than messing with the one in the instrument cluster.

 

Yes Matts, you are right
We used to pull the T-Stat back in the day just to see how the system runs
Problem is that with newer systems, some need the stat installed so we stopped doing that test

But you are right. He could pull the stat to see how it runs.
When he has the stat pulled, what temps does he run @ ?
And now it won't go into the Loop, so fuel econ sucks
Best to put a new stock stat in

 

Where is the temp sender located and how do you change it?

I am replacing my tstat today and possibly my guage tomorrow. Already changed the hoses and water pump. My fans are working but guage keeps reading in the red but car gives no symptoms of overheating except the guage. I have the airdam in place on my 72,000 IROC.

 

First off, I'm a newb, so take my advice with a grain of salt.

My car's sender is located on the driver's side of the engine, just behind the first cylinder, behind the spark plug. It looks like a little threaded brass plug with a metal tab coming out of it and a wire attached.

I drained most of my coolant out before I did mine, which I probalby didn't have to. Anyway, you unscrew the existing sender (if you dont drain coolant at least make sure the engine is cold and there's no pressure on the coolant). I used a crescent wrench because I didn't have a socket that would fit over the electrical connection on the sender.

If you don't drain coolant, unscrew the sender and pop the new one in and screw it in. Then reconnect the wire. My wire just snaps on and off. The sender is literally just a brass plug with a little metal rod that sticks into the coolant and an electrical connection tab on the other end.

I noticed that my existing sender had teflon tape on the threads. I was lazy and didn't put any new teflon tape on but nothing leaked.

That's it. I replaced mine with an aftermarket gauge, so it's easier to tell exactly what temperature I'm at. But it would be less work to just put in a new sender and see if the existing gauge reads it right.

I have a 195 degree thermostat right now and my old sender/gauge were reading something like 240. Put in the new sender/gauge and its reading 190 - 200.