Overheating under 20MPH

[Dzdimi14]

Do you have a fan shroud installed ?

yup

[Dzdimi14]

It would if the thermostat failed closed, my car would still stay around the middle of the gauge on the highway (maybe a little warmer than usual) and then climb up to near the top of the gauge when i stopped.


Do you have an infrared heat gun?

I just got an IR gun, how should I use it to diagnose my overheating problem?

[LJ851]

I just got an IR gun, how should I use it to diagnose my overheating problem?

You can measure the temp at the outlet of the head, the other side of the thermostat, temp at inlet of radiator, outlet of radiator.


When my thermostat was failing, i had 200+ degrees at the head and almost that going into the rad but like 90-100 degrees coming out of the rad.

[e30onBBSs]

When the engine is cool, feel your rad hoses. Do they feel like they have air inside of them instead of coolant? That's why my car used to overheat.

You can ground out the temp sensor to see if that's the problem. stick a wire in the plug and see if it jumps all the way to the right. When you pull the plug off the sensor it should just go all the way to the left. If these don't happen then there is a problem with the wiring to the gauge, or the gauge is messed not the sensor.