Well i went to a friends house to talk i let my truck idle for about 20 minutes and when i got back in the truck the bitch was pegged at 260.. so i rolled the windows down and turned the heater on then i went to drive around and it quickly dropped...keep in mind its about 80 degrees here and i had my a/c on the whole time it was idling..i know my thermostat is fine...this doesnt sound to out of the ordinary since its hot here and i had the a/c on but do you guys think i might have a problem? thanks!

 

I've heard of air-locks getting in the cooling system and preventing the coolant from circulating. Maybe sometime when the coolant isn't very hot yet you can hold the coolant hose and see if it feels like the coolant is flowing? Does it only overheat when idling or does it do this while driving also?

 

You running electric fans or a clutched on?

 

only at idle and no i dont have any electric fans

 

mine did something similar last summer while waiting at the bank for ever. i reved it for a fiew to get the fan turning and it droped. this summer i get to test how the electric fans work.

 

Either like yeary01z71 said you have air pockets or your clutch is bad. If you need a clutch, PM me I've got an extra you can HAVE just pay shipping.

Have you added a low temp thermo recently?