I have a 2003 with a 5.9L, automatic transmission and four-wheel drive. I have noticed lately the temp rises above what the truck normally did while driving in the city with my camper loaded and boat attached. It is most noticeable when backing up a steep grade and into my driveway. With that said it seems the cooling fan is not engaging like it used to when the engine warmed. I could really hear the air blowing from the fan. I checked the fan and I did not see any fluid leaks, and it still has some resistance when I try to spin it while the engine is warm. I am not sure if the increased temp is associated with the transmission warming up. I am looking for any suggestions on where to start.

 

Get the truck up to running temp without the A/C on and pop the hood. Put your hand above the opening above the fan and feel the air that the fan is pulling. Now go turn the A/C on and go back out and see if there is a big increase in the amount of air it pulls. On my truck there is a very big difference. If you don't feel much of a difference then your fan clutch may be going bad.

Also check to make sure the wires going to the fan are not cut.

 

Make SURE to check the connector located underneath by the radiator (slightly on the passenger side)

Open it up and look for corosion.

This prevented mine from engaging. It is now hardwired!

Chay