Tony the Liger

My fan clutch doesn't seem to be working. I've watched it while idling for probably a combined couple hour's worth of time or so at this point, and I've never seen it engage. The guy who helped me with my post-purchase maintenance suggested that there's a connection between it and the A/C not being all that cold, and that if I added freon, I might suddenly see the fan clutch engage. Does this make sense? Is the fan clutch just shot, or could the A/C issue be the problem, in which case I don't need to replace the fan clutch?

FWIW, I have to replace my water pump, so I was going to replace the thermostat, radiator cap, and hoses, and I considered replacing the fan clutch anyway just to complete most of an overhaul of my cooling system. But, if something else is preventing the current fan clutch from working, it doesn't make sense to replace it, only for the new one to never engage because of the same problem.

BrawnyDog

If you replaced the water pump, replacing all the other things you mentioned is a cake walk. All those things need to be replaced eventually anyway. Start your parts replacement clock now.

edit: nevermind, I read it wrong, but shaky is right. The mechanical clutch has nothing to do with anything other than heat. If it's not spinning then absolutely it needs to be replaced.

extrashaky

No. That does not make sense.

Fan clutches engage the mechanical fan based on either temperature or air pressure. I think ours uses temperature. At a low temp, the fan is allowed to freewheel to take the fan's load off the motor. As the temp rises, friction increases to turn the fan faster with the engine to pull more air through the radiator. It's a closed system. It isn't connected to the air conditioning or any other system on the vehicle. Your A/C system will not make it suddenly engage.

The symptom of a bad fan clutch is that your temp is fine on the highway but climbs in slow traffic or while idling. The reason for this is that on the highway, there's enough air moving through the radiator from the motion of the vehicle that the mechanical fan isn't doing anything. When you stop at a red light, air is no longer flowing through, so the temp rises. The fan clutch then engages to pull more air through the radiator. If the fan clutch doesn't engage or doesn't engage completely, it doesn't pull enough air, so you start to overheat.

If you don't see your temp rise at idle, the fan clutch is probably okay. On the other hand, fan clutches can start failing in a kind of half-assed way so that they just make the vehicle run a little hot in traffic but not overheat completely.

The only thing that acts on the fan clutch is temperature. The only thing that will prevent it from working is failure of the fan clutch itself.

It's not a bad idea to replace the fan clutch while you have the radiator out. That's when it's easiest to do. It's a little cramped right there with the radiator in place.

BlueRidgeMark

Yep. All of the above.