Tim114975

This is about were it usually runs maybe a little higher, It's gotten to the mark before the red when i shut it off and neither fans were running then.
Sorry I know this is a little too big on the photo

Injuneer

The gauge needle is pointing to ~185°F. What temperature thermostat are you running? Has the PCM been reprogrammed for fan on/off temperatures?

What are current ambient temperatures where you drive? Does the “running hot” occur at idle only, or also at highway speeds? A missing air dam under the front bumper will result in high temperatures at highway speeds.

If Freon pressure is low enough the PCM will not allow the compressor clutch to engage. Shouldn’t cause increased heat load to the cooling system.

After sitting for 2 years did you flush the cooling system, and properly bleed the air out of the system?

Use the testing guide linked in post #29 to verify you have 5 volts reference between the pins of the water pump temp sensor harness connector, key on, connector off the sensor.

Tim114975

Hello Injuneer, Sorry for the delay. I know you know what your talking about. I have a very long story that I’d love to share with you concerning this z28 outside the forum. Long story short everything is fine. The voltage checked out and at this point I let it idle trying to get the temp into the red. It would not get there because the fans would come on at low speed keeping it out of the red. I have flushed the coolant system several times and the fans are doing what you said they should. I’ve not drove this car in a very long time (I’ve been away 25 years) and I have forgotten about a certain hypertech program that used to be installed on the car. It reprogrammed the PCM to have the fans come on at a lower temp. Not sure what it is but I do remember changing the factory 180 degree stat out with a 160 degree which is what hyoertech called for. After reprogramming with Hypertech, when the fans come on they are on high as I remember. I’ve ordered new radiator cap and thermostat and I’m sure I will be visiting this site more as I continue to bring this baby back to life. Thanks