I thought the fan clutch on my shelf was good. Tried to turn it, and it resisted. Kept turning, it kept resisting. So I installed it. After running it for 300 or so mi., it only resists for half a turn, then spins.:banghead:
I wonder if the "my biggest fan" I put on, requires a "my biggest fan clutch"

Or, you can install a flex fan:eek: the only hard part is finding the right adapter for the pilot on the water pump.

OMG.. no flex fans, unless you like pulling blades outta your hood.there shouldn't be much resistance spinning the clutch cold. too test them. i've cardboarded off the rad so no air flow and fast idled it. getting up to wam temp, you should start hearing the whir of the clutch kicking in and out

OMG.. no flex fans, unless you like pulling blades outta your hood.there shouldn't be much resistance spinning the clutch cold. too test them. i've cardboarded off the rad so no air flow and fast idled it. getting up to wam temp, you should start hearing the whir of the clutch kicking in and out
Oh Yeah...You aint lived till ya seen that. I don't think they'd fly through the hood on a 6.2 due to the low RPM but I know what your sayin. I have seen them tear a hole right through the hood on a worked Chevy. Get a Hayden Severe Duty. They are only about 40$ from NAPA. IN fact I have a brand new one sitting in my garage for the Burb. Let me get the part #.

NAPA 273377 for my Burb which is a '90 OBS
2799 I believe is the Hayden #

Which is the "hayden"? the fan or the clutch?
I'm getting quite perplexed about my cooling issue. Picked up another fan clutch yesterday at the junk yard, that's all I can afford right now, Napa wants $218 for a new one.
Two Hundred and Eighteen dollars and some change.
My mouth hit the floor.
Anyway, my puzzlement goes something like this, my experience (or lack thereof) tells me fan clutch. But I own three, and all seem to work identical. Chances that I own three that are identically bad, small, not impossible but small. Wandered around the junk yard for about an hour, testing different fan clutches and none of them had as much resistance as any of mine. Also, when I shut down the engine when warm, the fan immediately comes to a halt. No after spin, none. While running (especially since I used the "my biggest fan") I got air blowin' big time in the engine compartment. It's blowing the dust and broken fiberglass fibers from the hood insulator all over the compartment.
Next puzzle, the rad in the rig looks much better than my spare, which I was convinced would have minimal flow, yet running a hose a full bore wouldn't fill one end, it flowed very well. The one I'm running barely has any deposits built up, so now I'm thinking flow is probably adequate.
When I re installed the rad back in Jan. I hosed through the fins to wash what I could, looked clean, but maybe it's time for another look, closer inspection? Think I'll try some oven cleaner, it's some pretty powerful stuff.
While at the junk yard I also came across an elec fan, biggest one I could find. Saw lots of taurus' there, thought about those fans but they looked awfully small. This one spins in the pull direction according to the arrow on the fan, If it'll spin the other way I'll use it as a supplement in front of the rad. This one is 19" across, the shroud in the rig is 21" across.

mercury has a flex fan on it. i figured it was cool how the fan blades went straight when it was reved to 5 grand. i guess i shouldnt have done that when i was looking at it with the hood up but meh lol.

Sorry guys, no flex fan on this rig. Now or ever.
The only stock flex fans I saw at the yard were on Lincolns, which IIRC ran a 400ci ferd. Oh yea, and goofy after market ones from stupid vehicles that people tried to "soup up".

218 for a fan clutch? WTF? :eek: Are they on crack?

It's listed at my work for like $60-70, and my job's expensive with parts.

mercury has a flex fan on it. i figured it was cool how the fan blades went straight when it was reved to 5 grand. i guess i shouldnt have done that when i was looking at it with the hood up but meh lol.

Those fans are can openers Brent. Problem is you would've been the can in that case. Normally the hood's the can that gets "opened" when one of those fans let go. No thanks, I'll stick with the clutch fan.

Just an FYI for anyone debating going this route, I was going to use a clutch fan from a 6.5 since i had one and it's a 9 blade fan but the hub where the fan bolts to the water pump is too small on the 6.2 waterpump, so that's a no go.

I know that Napa isn't the cheapest place in the world. But I have found that they USUALLY sell good quality parts. Unless of coarse, you go with their cheapest stuff, then you get the same stuff you get from [place you're crummiest parts place here]. My first thought on that Dave, is what brand? (Not that I know what Napa is selling)

If you want a good clutch, check with Kennedy diesel or Heath. I have run GOOD stainless steel flex fans for lots of miles and never had a problem and you have a 50.00 investment. Good clutch fans aren't cheap. I used to modify stock clutch fans to come on at earlier temps to help with cooling on turboed engines towing heavy. The hayden hd clutches are ok, but they aren't the same quality as the oem units.

Thank you!
Ok, I lied. Again.
One of my fan clutches is different, and feels better.
The one I picked up at the junk yard (the shiny one) came from a 3/4 ton, J code burb. Little beefier, and more resistance when spun by hand.
I forgot to note how the fan was positioned on the clutch before I removed it. I hope it doesn't make a difference, if so I hope I got it on there right.
Oh yea, saw this note on the one that says " store this side down". thought I'd through that out there for those who have fan clutches laying around.

Just got back from a test run up THE hill by my house. Never got over 200*.
WOOOO-HOOOOO!!!
The combination of the HD clutch, and cleaning the rad made a world of difference.

Since you posted nice pictures, if you look carefully at the center in the front of the clutch, you will see a spring. The spring is attached to a shaft, as the spring heats up, it turns the shaft the shaft closes a valve that restricts the flow of the silicone fluid inside the clutch. Cutting a different notch in the bracket will allow the clutch to engage at an earlier temp. Taking the spring completely out of the bracket also works, but usually makes the clutch engage too early and that isn't a good thing, because when locked up, the fan will draw a lot of hp.

Thank you! I'll post more pics from now on!!!!
Very interesting, I figured the shaft rotated, but never thought of modifying the clippy thingy. So, I'm assuming the spring wants to unfurl as it heats?

Heaths clutch is nothing more than the hayden rebadged. The Hayden Severe Duty is about 40$ from NAPA. Don't know who the hell gave you the price of 218. I just bought one. You can bend the spring on the front to make it come on earlier.

i just looked up on NAPA and they don't list a fan clutch over $50. but then when i looked at 6.2 there were none. thats probabaly a special order price. rock auto has hayden for a 6.2 for $55 and its a different model number than the gasser ones. i'm sure when i got one for my truck years ago i just got a gasser one. they just wanted to know if it waas standard rotation

Look it up by part #. Thios is the severe duty one...
http://www.dieselplace.com/forum/showpost.php?p=3821428&postcount=5

Thanks guys, I'll definitely keep this in mind for my build. Not going with junk yard parts on that! But for now my $17 pick-n-pull clutch is working.

Since you posted nice pictures, if you look carefully at the center in the front of the clutch, you will see a spring. The spring is attached to a shaft, as the spring heats up, it turns the shaft the shaft closes a valve that restricts the flow of the silicone fluid inside the clutch. Cutting a different notch in the bracket will allow the clutch to engage at an earlier temp. Taking the spring completely out of the bracket also works, but usually makes the clutch engage too early and that isn't a good thing, because when locked up, the fan will draw a lot of hp.

good info, thanks

it would be something to see a flex fan lose a blade turning at 3500rpm, maybe on a gasser that revs out to 6000rpm......;)

I think flex fans look about like the pin striping or "flames" stickers that you buy at autozone.
And from the one I've seen, those tiny little blades won't move half the air that "My biggest fan" does.
Now, (next) I'm thinkin external coolers. Both oil and trans fluid. Get that heat out of the rad.

Since you posted nice pictures, if you look carefully at the center in the front of the clutch, you will see a spring. The spring is attached to a shaft, as the spring heats up, it turns the shaft the shaft closes a valve that restricts the flow of the silicone fluid inside the clutch. Cutting a different notch in the bracket will allow the clutch to engage at an earlier temp. Taking the spring completely out of the bracket also works, but usually makes the clutch engage too early and that isn't a good thing, because when locked up, the fan will draw a lot of hp.

sorry for reviving this thread but its only a week old so sue me.;) anyways, do you have any specs on where to cut a notch in the housing? i want to mod my spring since my truck heats up a bit further than id like.