It was hot yesterday after work and I was driving my 98 home and had the AC going. I noticed it started getting hot, kicked off the ac, and the temps got under control in like 1-2 minutes. I need to check my fans out.

 

Note to Swank - if truck began overheat while driving AND AC on, the condensor fans may not be the problem. The extra heat from the AC is being blown back on the main radiator. If problem is happening only when slow or at idle, many times the viscous fan clutch is the issue. If it is happening while driving home, and you are at 45 MPH or better much of the way, then your radiator could be marginal, might need to flush it. Radiators age slowly, calcium build up from failue to use distilled water (in hard water areas of the country); and previous owners tossing in two bottles of radiator stop leak before selling the truck....

 

Thanks for the heads up. It was while driving highways speeds 60-75mph. I'll flush my cooling system out and check out my fan clutch. I was suspecting my fan clutch. I bought the truck in Jan this year and live at 9400 feet. It hasn't seen hot weather driving yet until it overheated. Thanks for the heads up. It's oil is pretty clean (no water) when I change it, the coolant looks pretty good, and it passed emissions with flying colors and runs well.