Early 1FZ Fan Clutch (Black/Blue Hub)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Well, hell! My fan clutch locked up on me. After PMing it by draining the old fluid out and replacing it with 10K cst, I noticed black specks in the old discolored fluid which Kevin (Tools-r-us) suggested that could be an indication the bearing was going. After returning from a 300+ mile road trip Sat. Night and checking under the hood Sunday Morning, I thought I'd feel the fan clutch - well.... I thought it was a clutch. But, no, it's locked up solid. And it's been fairly cold lately: 0-20*F nights and 30*F days. Any ideas? It's the original black Aisin. Could it be just the cold weather and getting the engine up to operating temps free it up again? Damn, I was hoping to get another 50k - 100k miles out of it! :bang:
 
Tom,
Check to see if it unlocks once you get it good and warmed up.
Since you have thicker fluid in there, it may take a bit of time to move thru the clutch.
 
FirstToy said:
Tom,
Check to see if it unlocks once you get it good and warmed up.
Since you have thicker fluid in there, it may take a bit of time to move thru the clutch.
Click to expand...

I'm hoping you're right, FirstToy! But, I got this sick feeling that the bearing's gone. I started it up Sunday, for about 10 minutes, thinking the centrifugal force of running and engine heat might free it up. Revved it a little, hoping to hear the "roar" subside. But, the roar stayed and sure enough, when I shut it off, it was still locked up. I'll try and run it longer & get it good & warm this weekend. I'd sure love to not have to tear it down in this weather. I don't have a garage that it fits in since I re-located here to John Day. I'm not as young and limber as I used to be. Thanks for the ideas!
 
Last edited:
Sounds like the bearing died.:frown: Have seen 1 bad on an Eaton, this is the first on an Aisin. They are very durable, but it can happen, even to the best of them.

The locked bearing doesn't preclude driving, but be careful with RPM. The fan is not designed to run at full shaft speed, so can come apart and that can cause $$$ damage. Time for a new clutch.
 
Thanks, Kevin! I'm pretty sure you're right. After some reflection, I can't see the cold causing clutch to lock up. Have you got any old black hub Aisins that are in good shape? At one time sounded like you were collecting them. If you want to part with one, PM me your address and I'll send you a check for clutch, fluid and shipping. I'd rather go that route than the new blue clutch.
 
80t0ylc said:
Thanks, Kevin! I'm pretty sure you're right. After some reflection, I can't see the cold causing clutch to lock up. Have you got any old black hub Aisins that are in good shape? At one time sounded like you were collecting them. If you want to part with one, PM me your address and I'll send you a check for clutch, fluid and shipping. I'd rather go that route than the new blue clutch.
Click to expand...

I don't have any spare clutches. A blue hub should be fine for your area/use? Just stick some thicker fluid in and call it good?
 
Tools R Us said:
I don't have any spare clutches. A blue hub should be fine for your area/use? Just stick some thicker fluid in and call it good?
Click to expand...
Thanks for your advice. I'll study up on the blue clutch and figure out how to set it up for my area/use.
 
i have a spare green hub that came off 91 will this work on a 1fz? is it better then a black hub
 
Well, $174 later (including shipping) - I got a brand new blue hubbed fan clutch and 10k fluid coming by the brown truck from cdan. I guess I shouldn't have to worry about a bad bearing for a while, and 230K+ miles out of the original is way above average.
 
FirstToy said:
Tom,
Check to see if it unlocks once you get it good and warmed up.
Since you have thicker fluid in there, it may take a bit of time to move thru the clutch.
Click to expand...

It got up near 50*F today and got it up to operating temp. Still no joy, although it feels not as tight (see below explanation)

Tools R Us said:
Sounds like the bearing died.:frown: Have seen 1 bad on an Eaton, this is the first on an Aisin. They are very durable, but it can happen, even to the best of them.

The locked bearing doesn't preclude driving, but be careful with RPM. The fan is not designed to run at full shaft speed, so can come apart and that can cause $$$ damage. Time for a new clutch.
Click to expand...

Kevin, it doesn't really feel like a seized bearing. I can move the fan tip about 2" and the front to back play feels solid. I believe it feels a little more free in this warmer weather than it did last weekend which was 20-30 degrees colder. If I were to guess, I'd say it feels like something's fubar inside the clutch (plugged valve or something?). I'll know when I disassemble it when the new clutch gets here later this week (I hope).
 
80t0ylc said:
...
Kevin, it doesn't really feel like a seized bearing. I can move the fan tip about 2" and the front to back play feels solid. I believe it feels a little more free in this warmer weather than it did last weekend which was 20-30 degrees colder. If I were to guess, I'd say it feels like something's fubar inside the clutch (plugged valve or something?). I'll know when I disassemble it when the new clutch gets here later this week (I hope).
Click to expand...

Sometimes bearings fail by the cage that holds the balls breaking, this can jam the balls, so it only gets a few degrees of movement. Something else could have happened, like a valve screw backed out, etc. Hard to tell until it is apart.
 
Got the new clutch today. I opened it up and am draining the original fluid out. Here's pics of the way it came adjusted. Kevin, you've said in other threads to leave the adjustment alone and just drain & add the thicker fluid. Does it look good to go from what you can tell?
HPIM0758.webp
HPIM0759.webp
 
The only way to tell is; heat the spring (I use a heat gun) watch the valve and record the spring temp. That said, don't think that I have ever seen an Aisin that needed adjustment. All the I have done have been fill and go.
 
Tools R Us said:
The only way to tell is; heat the spring (I use a heat gun) watch the valve and record the spring temp........
Click to expand...
How do you measure the spring temp? Could you use a non-contact laser thermometer? What's the latest determination to set it at? I've been studying threads and there seems to be a difference of opinion so far.

Tools R Us said:
.......That said, don't think that I have ever seen an Aisin that needed adjustment. All the I have done have been fill and go.
Click to expand...
I like this method, better. Easier and I'm lazy:hillbilly:. I'm going to drain this all night and all day tomorrow while I'm at work. Should I go with 55ml for the refill? I had cdan send 3 tubes of 10K with the clutch. Thanks again for your help and advice! :cheers:

Edit: one of the tubes got smashed in shipment, but I had 20ml left from refilling the OEM black hubbed Aisin.
 
Last edited:
Interesting results:
At 87*F both holes are completely open.
At 83* both are somewhat half closed on cool down.
And at 74* both are closed.

Temps were read on spring shaft at spring with a laser no touch thermometer. Shaft was a bigger mass and held temp longer than spring itself. But the difference was only a couple of degrees between shaft & spring. Is this good for out of the box and continued performance? At the beginning of Landtanks thread, he was talking adjustment at 95*, but that was 4 yrs ago.:confused:
 
Tools R Us said:
The only way to tell is; heat the spring (I use a heat gun) watch the valve and record the spring temp. That said, don't think that I have ever seen an Aisin that needed adjustment. All the I have done have been fill and and complain about their week performance.
Click to expand...


fixed it
 
landtank said:
just what I've posted in my thread. I tune them for the valve to be half open at 95* and am now using 15k oil.
Click to expand...

OK, thanks! I'm just verifying. I've done a lot of reading lately of some long threads. I remembered that's how you set yours up (temp) at the beginning of your thread 4 yrs ago. A lot of activity since then. I don't want to have to bust this thing back open. Aren't you running a SC on yours? Do you think 10K will work at 95* or should it be set different for that weight? Thanks for your advice!
 
You must log in or register to reply here.

Share this page

Back
Top Bottom