I think you are onto something regarding the fan clutch. I have not heard the fan clutch "howling/spinning" on a hot day when taking off from a stand still. I have also noticed that if I am idling in one place for about 5-10 minutes, the engine temp will rise to about 210-220 degrees and continue to rise. So maybe the fan clutch needs replacing.
If that a diffucult task or should I let a tech replace the fan clutch. It doesn't seem like a hard job, but I am not sure if I have the right tools.
Any assistance would be great. Thanks guys.
I bought a new fan clutch Friday for the 99 again. This will be the second time I replaced it. (214,000 miles now) I think the factory clutches seem to go about 70-80,000 miles based on my sample of two.
The fan clutch has a 1 7/16" nut on it that threads onto the waterpump shaft. It's a standard (righthand) thread. Remember, "righty-tighty, lefty-loosey"
It's been so long now, I don't recall if the upper fan schroud had to come off or not. Probably easier if it does.