I was wondering if anyone has a good way to check the cooling fan clutch on a 3.9. My truck when it sits for an extended period and I start it up and take off the fan sounds like it belongs on an airplane. After the trans and motor shift into second the noise goes away and doesn't come back. I was wondering if this is normal or should I look at getting it replaced. I just replaced water pump and don't feel like doing it again anytime soon thanks

 

mine does the same thing. I'm not sure why, either.

 

It's normal for the clutch to engage and make the roaring noise like that after the truck sits for a period of time, whether it is a few hours or overnight. The fan clutch should disengage and allow the engine fan to turn after driving a short distance, usually less than a quarter of a mile. If it stays locked up and roaring longer than that you probably have a bad fan clutch. You can also check the fan clutch by turning it by hand. With the engine cold and not running, give the fan a good solid push toward the passenger's side fender. The fan should travel only a short distance, maybe 4 inches or so and stop. If the fan travels further than that, or if it is either super easy or very hard to turn by hand, the fan clutch is bad. Some say it is best to replace the fan clutch when you replace the water pump because both parts have about the same life expectancy and when one is worn out, the other is not far behind. I believe that to be true. Last year I replaced my water pump in February and then in August I had to replace my fan clutch.

Jimmy

 

thanks I'm gonna wait at around 150$ in Canada it's a little bit steep

 

Screw that. Mine was fine but I just took it off. I've driven in 104 degree weather and the needle hasn't gone above the halfway mark.

 

I'm taking mine off to do the Mark 8 fan.

 

I'm not even worried about adding an additional electric fan. The electric fan for the transmission cooler is plenty for now.

 

Hotter here in Tx + my AC elec fan has gone toasty.

 

holy you took off the fan as well I assume. I don't trust the temp sender in these trucks drove a 94 around for a year t stat was stuck open and truck showed just below midway the whole time never warmed up was about to change heater core when I found t stat

 

At one time, an autometer sender/gauge was on my to-buy list, but never got there. I have a 180 thermostat so things circulate sooner, the mark8 fan outperforms most clutch fans without question. I worry about overheating if i'm not moving since the clutch fan is doing all the work, but once I switch i wont have that problem.