On my '92 4Runner the fan will run for a minute or two when cold and then stop spinning. It's a very audible difference; the engine quiets down considerably once the clutch disengages.

Once it gets hot, it again starts spinning.

On my 280ZX the fan started with engine start (at 90 degrees ambient) and never quit spinning today after I replaced some heater hoses and let it heat up, radiator cap off, to "burp."

How about yours. Does it quit spinning on a cold startup?

Like me, you probably never pay any mind to it until you develop an overheating problem.

I'm thinking I"m due for a new fan clutch.

FastWoman wrote up a procedure for rebuilding the fan clutch. It's out there somewhere. Involves replacing the silicone fluid inside, apparently it gets gummed up and stops flowing correctly.

Wouldn't be surprised if there was something on atlanticz.ca also, although I haven't checked.

I didn't think the clutch ever allowed the fan to stop spinning, just to limit the amount of rotation - very possible that I'm wrong here.

On my 280Z, the fan spins from first crank to shutdown. I'm not sure if the operation of the ZX's clutch differs from that.

"I'm thinking I"m due for a new fan clutch."

I've never seen the fan not turning while the engine has been running in my '71 S30 and I've owned it since new. By running continuously yours may be working fine.

On the other hand, Carl Beck wrote that he has seen six fan clutch failures and the results were ugly.

Fan Clutches are available from NAPA, MSA and Z Car Source and eBay to mention a few. The price varies from $50 to $200. So, if in doubt and you want piece of mind, the cost is not too bad and they are straight forward to replace for yourself.

Just my two cents, not all fan clutches are serviceable, some are sealed units, can't even unscrew 'em to try and replace the goo inside.

I do know that I picked up a late mode Altima twin electric fan assembly from the local junkyard for under twenty bucks. Not everybody is gonna have relays and wiring laying around, but even with that stuff it's well under even the cheapest Chinese made replacement fan clutches.

I have never seen a fan clutch that doesn't spin (at least to some degree) whether it's working properly or not. My experience in the past has been: 1) It locks up and makes one hell of a noise (similar to a jet engine taking off), reduces efficiency, etc. 2) Starts failing and engine starts running hotter than normal till it starts overheating. Well, okay, there was one 3) that stopped completely on my mom's car (which I was driving at the time, (age 16)) only after IT and the FAN went through the radiator (VERY BAD DAY!...). RE: Rebuilding... I've not heard of it, but obviously some of them are repairable, so good luck. I'm going to do some "searching" on the site to see if I can locate the link. Good luck guys!