Temp Guage spiking up when ac is on and at idle

[Tahoe4x495]

Hey guys I got a 95 chevy tahoe ls 5.7 liter 350. When I'm sittin at idle with the ac on. My temp gauge will go from 195 to roughly 230 but while I'm driving it'll go back to normal temperature. Its also the same with the ac temp. It'll blow warm at idle but blow cool while driving. Any suggestions?

 

[OR VietVet]

Check for failing/failed fan clutch and check for any air flow restrictions at the radiator and condenser. If has run that hot I would change the thermostat also and verify the rad cap is still good.

 

[Tahoe4x495]

Alright thanks I'll check

 

[mattss90]

My 96 blows cold after about 10-15 minutes of driving. It blows cool air in park but blows cold air while driving. I'm thinking it's just either the age of the trucks or old technology. I don't have an answer for you but maybe some insight of the tendencies of these GMT400 trucks.

Btw, my truck runs at 165-180ish when warmed all the way up. Came close to 200 only while wheeling. But Idk if that's the difference between the 96 vortec and the old school TBI you have in your 95... Good luck to you. Come back and let me know what the deal is if you figure it out!

 

[Tahoe4x495]

For sure thanks I'll be sure to update once I have it fixed

 

[SunlitComet]

mattss, you are running a bit to cold. You should see about 195° when looking at live data from pcm.

 

[Tahoe4x495]

Hey guys. I replaced my fan clutch with a new heavy duty fan clutch and it fixed my problem. Thanks for all the advice