I posted about this a while back (4 months ago) but thought it would be better to post again in a new thread now that I can understand the responses better.

When are clutch fans suppose to free spin? I use to think only at highway speeds, but reading back on some other threads I get the impression they're also suppose to free spin at any speed when the truck is cold.

My truck takes too long to warm up and it's far too noisy at idle/fast idle.
I can move my fan easily by hand.

If I went out and bought a new clutch fan, would it not spin (or spin slowly) at 1600RPM(fast idle) to 800RPM when it's 10, 15 or 30degrees outside?

I have to quiet down my truck somehow, by quite a bit. I also want it to warm up quicker in the winter.
I could go to an electric fan but for a dozen different reasons, I don't want to, but I'll have to if I can't figure out a more efficient way to cool my truck.

I remember my truck warming up quicker than this in the past, but so many factors have changed since then.

Seriously, it's bad. I can't hear an exhaust leak at the manifold over the stupid fan at idle.

 

http://www.autozone.com/R,APP237799/...ductDetail.htm

this is the one I'm looking at, non-AC. Should bolt up to my 7 blade fan, right?

I don't want to spend $60 without knowing if it will help or not.

 

Thermal clutch fans should engage for a couple of minutes when cold, then release untill the air through the radiator gets hot enough to engage it. Non thermal type will just freewheel all the time.

 

Im not sure about 400s but on 460s there are 2 types of fan blades/fan clutches. The truck fan blade has a much bigger hole in the center to fit the much bigger fan clutch through. Just make sure your clutch fan flange that bolts to the water pump will fit through (but isnt sloppy in the hole) your fan blade before you buy. Experience talking

 

When buying a fan clutch you need to measure the ID of the center hole and bolt hole pattern and make sure the fan clutch mounting flange is the same size. My 77 F150 came with out a fan clutch setup, so wanted to add one, so I got a 7 blade fan and a new fan clutch off eBay from different auctions and when I received them they would not work together for reason stated earlier.

 

Well, there are two clutchs at AutoZone, one with AC and one without. I'll just take my current one in and make sure the fan fits onto the clutch.. thanks for the warning though , I would have just bought it without testing it first.

and it definitely sounds like my clutch is busted, stuck in the 'engaged' position. I've tried turning the spring by hand and it didn't seem to reduce the friction when turning the fan by hand, apparently it should.

thanks all