gpet6669,
Tell me what you know about the fan and fan clutch...

 

What do you need to know about the fan? I changed my clutch because my fan would stay on all the time. It was easy!

 

I found out the fan clutch is pretty much not working. Is a fan clutch easy to replace?? A mechanic told me to switch to an electric fan..is it worth the change??

 

I guess I am a little late but what you described is typical fan clutch failure. At an idle your motor isn't turning high RPM's so the clutch is able to still move some air. When you accelerate the clutch basically slips and moves less air than when idling. I wouldn't worry about an electric fan. Just replace that factory clutch. You will probably need to rent a fan clutch removal tool from your local auto parts store if you don't have one. I know the stores around here basically rent it for free (you pay for it and bring it back and they give you a full refund).

 

It can be a bit difficult to remove. I use adjustable wrench and a hammer to break them loose. Then they screw off easily. You need to remove the top half of the radiator shroud as well. Once the clutch/fan assembly is off, you just unscrew the fan and mount it to the new clutch, then re-install everything.

 

Hello, I am new to this forum and I know this is an old thread, but I was wandering if you ever found the problem. My 1998 K2500 is doing the same thing. I just changed the thermostat (195 deg) and the same thing happens.