So i just bought an 86 iroc and i do not trust the stock temperature gauge reading. It seems like it never goes beyond like 150 so either the cars running really cool or the sender is off.

What im wondering is how can i get the the most accurate temperature reading? Im considering getting an aftermarket gauge but id like to know where i should hook it up to get the best reading.

Also is there anyway that i can test the stock gauge for accuracy?

Thanks for any input

 

IDK about testing the stock stuff, but after this many years, it could have problems.
Temp senders should be connected at the front of the intake manifold, where the coolant passages from each head cross toward the t-stat in the middle. There should be threaded bosses to either side of the stat, you're interested in the driver's side.
The stock setup may well be threaded into the adjacent head, between the front 2 exhaust ports.

 

Well the car doesnt have the stock setup it has a rebuilt carbed 350 with a weiand intake. The only thing i see that looks remotely close to a temperature sensor is located between the first two driverside header pipes. It looks like a coolant temp sensor, but im not 100%. Ive checked around by the water neck and cant seem to find any place to thread anything in or anything that looks like a sensor.

Any ideas?

 

Heres a picture

 

I'd start by trying another stock sender. That should be cheap and easy. I'd also test the stock wire with an ohm meter for resistance. And I'd check that the gauge has a good ground and is getting 12v.
If you do this yourself, it might take an hour or 2, but is cheaper than just buying a new AutoMeter gauge.
Also, I'd replace the old thermostat with a new 180, and don't forget to drill a small steam hole in the new one. Assuming you have a turkey thermometer in the kitchen, thermostats can be tested in a pot of water on the stove.

 

Not sure if there is a variance in gauges, but the temp gauge my 89 Iroc has is pretty accurate. Its got one line at 100 deg and one line at 220 deg. Theres a hash mark half way between those 2 marked lines, and guess what? Its NOT exactly a half way mark. You'd expect it to be 160 but its actually closer to 180 on my car. When the car hits 220 (if i ever let it) its dead on 220 on the gauge. Normal cruise is high 180's or so in the warm summer air, sometimes getting to the lower 190's and the needle points alittle bit beyond that half way mark.

verified with datalogger and lazer temp gun on the coolant lines.

 

Well this is the temperature my car gets to and stops. Im not sure if this is considered the norm although i do get some pretty good air in my engine bay from the big block hood's cowl induction.





Im used to the other gauge set up in the late 80s thirdgens. But still on a hot houston day i would expect higher temps.

 

verify the sensor is the same type to work with the stock gauge. What T-stat do you have in the car? Is it ported?

That looks to me closer to 180-185 deg which is good. Probably have good cooling fan flow and a low temp t-stat. If its stock t-stat or higher than 180, then it seems abit cold for the weather. Its hot here.