Factory fan clutch fluid replacement, still won't engage (2 Viewers)

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Successful update!! See Post 18 - Factory fan clutch fluid replacement.

I have two factory fan clutches that were discovered faulty after temp gauge mod and outside temps warming up. I first bought a Hayden unit from Napa and the loud roar was there and temp gauge stayed in the middle. I wanted to try out the fluid replacement so I picked up two bottles of RC diff fluid, one 40mL of 6K, 50mL of 10K. Drained and filled one bottle in each of the clutches. Tried the 10K first, outside was 70-80 at first the gauge was 1/3 for an hour trip and I thought life was grand. Then the next trip it went up to the bottom of the red, into the red if I push it, slight drop if I turn off A/C and slightly more if I run heater, wouldnt drop unless I idled in P/N or turned it off. A/C did not cut off, still cool. Tried the other cluth, again got a slight roar at start up, initial low temp, then running hot with no clutch engagement.

I put the tops in the oven and the ports opened but maybe at too high temp? What am I doing wrong? Can the unit itself just be bad? BTW these are standard late clutches, NOT blue or black hub. All test driving done on hilly roads at least an hour trip each time, little extra weight, usually the red zone was towards the end of the hour trip. I read the clutch fluid replacement threads and everyone seems to have success with it, I can't figure out what I ddi wrong, please help! TIA!!
 
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The mod is optimized for the Aisin clutches, each type of clutch has different shearing area. For instance if 10k fluid is put in a late blue hub and an early type blue or black the late clutch, the late type wont perform as well, it takes ~14K in the late type for them to perform about the same.

I haven't had a Hayden apart. But all of the aftermarket clutches that I have had apart are smaller in diameter and much cruder/smaller shearing area design. Logic would dictate that they would require much thicker fluid to do the same job. In other words if they come with 50K fluid, "upgrading" to 6K wouldn't work well. This is an unknown on the aftermarket clutch.

The other possibility is the fluid you have isn't the correct stuff. This is unlikely, the R/C car diffs work on the same shearing principal and the hobby store stuff is well proven.
 
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The mod is optimized for the Aisin clutches, each type of clutch has different shearing area. For instance if 10k fluid is put in a late blue hub and an early type blue or black the late clutch, the late type wont perform as well, it takes ~14K in the late type for them to perform about the same.

I haven't had a Hayden apart. But all of the aftermarket clutches that I have had apart are smaller in diameter and much cruder/smaller shearing area design. Logic would dictate that they would require much thicker fluid to do the same job. In other words if they come with 50K fluid, "upgrading" to 6K wouldn't work well. This is an unknown on the aftermarket clutch.

The other possibility is the fluid you have isn't the correct stuff. This is unlikely, the R/C car diffs work on the same shearing principal and the hobby store stuff is well proven.

The two that I replaced the fluid in were the stock clutches, production dates were 95 and 96 for the 96 and 97 model years, the Hayden is untouched and only used for a "control" unit. I can tell that the clutches are pulling some air just not very much, no roar or wind tunnel like the Hayden.

The fluid I used was from Japan, the 6K was exactly the stuff in Bear80's thread, the 10K a different brand but was "of the same high quality" (pic below) The dark stuff was removed from one of the clutches.

So the 14K in a late non adj. will act like 10K in a blue hub? What shoud I try or will it be a trial and error? In that case I might be better off ordering a blue hub?

Thanks for the help, it's getting warmer and I hope to solve this before it gets hot!
bP1040217.JPG
 
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Sorry, I misread that you were working on the Hayden. Those production dates would be the the Eaton clutch? IMHO they slightly less quality built when compared to the Aisin, but several locals are running them with thicker fluid with good results. We find them to respond to thicker fluid about the same as the Aisins. Don't understand why your having issues, maybe some pix would help?
 
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Wow, I'm glad I spotted this thread!

Guys, I need your advice.

I have a 1991 FJ80 that's been converted to an HDJ80 with the 1HD-T toyota turbo diesel engine.

It's getting hot on the trails, I'm pretty sure the fan clutch is toast.

I want to buy some of the silicone oil, and I'm thinking that the thicker stuff is more likely to be the one for my application, rather than the thinner stuff.

So, where do you buy this silicone oil? I know that some toyota stores till stock it, but I think maybe the aftermarket sources might be better?

I'm thinking maybe the equivalent of the 10K stuff.

BTW, what exactly does 10K stand for? I guess it's measuring viscosity, but what is the measuring unit?

BTW, after doing a number of google searches, I found that the Porsche 928 has a very similar clutch to the landcruiser, and that some of the 928 forums recommend using the toyota silicone oil to repair their clutches.

thanks

Dana
 
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The measure of weight is cst. Not sure what it stands for, but it is a measure of viscocity.

I bought it on ebay as I don't have a hobby/rc shop anywhere nearby. On ebay search "10000 silicone oil" and you'll find it.
 
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The measure of weight is cst. Not sure what it stands for, but it is a measure of viscocity.

I bought it on ebay as I don't have a hobby/rc shop anywhere nearby. On ebay search "10000 silicone oil" and you'll find it.

OK, I looked on ebay, and there was one seller that said cst stands for "centistokes @ 25deg celcius"

His "diff oil" for R/C diff applications was rated at 100 cst, so i'm not sure this hobby oil is anywhere near the required viscosity. ebay item 300315023275
 
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OK, I looked on ebay, and there was one seller that said cst stands for "centistokes @ 25deg celcius"

His "diff oil" for R/C diff applications was rated at 100 cst, so i'm not sure this hobby oil is anywhere near the required viscosity. ebay item 300315023275

Here ya are: Mugen #10000 Super Silicone Diff Oil MUGB0317 - eBay (item 250420547592 end time Jun-06-09 12:32:55 PDT)

This is the Mugen oil that I and others have used.

The clutch looks familiar, thats the ones I have and I filled with the Mugen 10K pictured in post 3.

TRU, I can post pics of the clutches but they just look the same as the link above, what else did you have in mind?

That clutch works great in my Cruiser with the 10,000cst.

Check the opening temperature in a pot of water monitored by a cooking thermometer to see when/if it opens. There really isn't much to these things. It appears to me the only things that can go bad are the thermostat spring (located on the back) which regulates the opening, and the o-ring. I've heard in rusty areas of the spring rusting out.
 
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The clutch looks familiar, thats the ones I have and I filled with the Mugen 10K pictured in post 3.

TRU, I can post pics of the clutches but they just look the same as the link above, what else did you have in mind?

I have nothing.:confused: In my experience the Eatons have responded well with a fluid change. I have only used the Ofna and Associated fluid, but others have used the Mugen with good results. Thought that someone may spot a problem in a pic, but the clutches are pretty simple, so unlikely?
 
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guys, I did a search and came up with some of the earlier threads on this subject.

They're pretty long!

My hub color is tan.

The clutch is probably original to the engine, which is 1990 vintage.

I haven't taken it off the truck yet, so I don't know what brand the clutch is.

I can't devote the time right now to wade through these lengthy threads. In the few pages I did red, there was discussion about whether just an oil change would rejuvenate the clutch, or maybe it was necessary to heat and adjust it also. And, there was discussion about what viscosity fluid to use.

So, could some of you who participated in them please tell me the bottom line: Do I need to just change the oil? Do I need to get a thermometer and go through that procedure? And what cst rating oil is the best for these cruisers.

I live in LA, and more of my wheeling is in the deserts than in the mountains, so I'd be more within the "Oz-spec" than anything else.

recommendations?

thanks

Dana
 
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guys, I did a search and came up with some of the earlier threads on this subject.

They're pretty long!

My hub color is tan.

The clutch is probably original to the engine, which is 1990 vintage.

I haven't taken it off the truck yet, so I don't know what brand the clutch is.

I can't devote the time right now to wade through these lengthy threads. In the few pages I did red, there was discussion about whether just an oil change would rejuvenate the clutch, or maybe it was necessary to heat and adjust it also. And, there was discussion about what viscosity fluid to use.

So, could some of you who participated in them please tell me the bottom line: Do I need to just change the oil? Do I need to get a thermometer and go through that procedure? And what cst rating oil is the best for these cruisers.

I live in LA, and more of my wheeling is in the deserts than in the mountains, so I'd be more within the "Oz-spec" than anything else.

recommendations?

thanks

Dana

For desert running I would go 10K+ on the fluid. There is a good thread in the mini forum that explains the process without all of the extra discussion. The mini clutch is very similar to yours.

https://forum.ih8mud.com/79-95-toyota-truck-tech/167678-fan-clutch-service.html
 
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I have nothing.:confused: In my experience the Eatons have responded well with a fluid change. I have only used the Ofna and Associated fluid, but others have used the Mugen with good results. Thought that someone may spot a problem in a pic, but the clutches are pretty simple, so unlikely?

Well thanks for helping anyway. It does open as I hit it with the heat gun and put it in the oven but I havent had time to go to the store and get a meat thermo and an extra pan so the Mrs. doesn't kill me for using her good ones so I dont know at what temp but they do oopen about the same time so if they were faulty I think it unlikely they are off the same amount but who knows. The springs are a little rusted but not too bad so I used brake cleaner and a wire brush and scrubbed it pretty good and now I'm playing with the spring tension a little to see if it is adjustable by some sort. So I threw the 10K back on and got a roar at start up so I'll see if stays cool while driving a good distance.
 
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For desert running I would go 10K+ on the fluid. There is a good thread in the mini forum that explains the process without all of the extra discussion. The mini clutch is very similar to yours.

https://forum.ih8mud.com/79-95-toyota-truck-tech/167678-fan-clutch-service.html


Hi Kevin, thanks for the reply.

I haven't yet removed the fan clutch, but from what I've been told by a guy in Holland that works on these diesels, they are adjustable and very similar to the gas powered 80 series clutches.

I kinda mis-spoke when I said I usually run in the desert. I avoid the heat, so when I run in the desert, it's not really that hot. I will find cooler spots to run in the summer, up at elevation. So when you think desert in AZ, it's quite different than when I say desert. If I'm running in 110 degree heat, it's because I got stuck in it, it's not because I chose to do it. I'd guess that most of the time I'm well under 100, usually even less than 90 during the hot months.

I did finally read all the way through the thread, wow that was long. I'm really confused now. I know the different camps: adjust, or add heavier fluid, or do both.

What I'd like to end up with is a fan that acts like an electric fan. I'd like to get the economy of freewheeling on the highway, but when I'm wheeling on a slow trail, working the engine, I'd like the fan to cut in as necessary and really pull some air so the engine temps drop fast. So I know I'll need a heavier oil, but I "think" I need to keep the cut-in point at a pretty high temp, like 110-115 degrees or so. I really don't want the fan to come in on the highway, and I think it might if the clutch is set to 95. This truck has no electronics, so no obd to look at, and no temp gauge mod. I can tell you the thing usually lives at the half-way point. It never warms up on the freeway, only slow crawling up a steep hill in warm ambient temps.

Also, I really don't drive in super cold weather much, but do sometimes, and I don't want it to misbehave in cold weather, as it did to some folks on the thread.


So, I'm thinking I'll check the setting of the clutch, try and get it to open around 115, and then drain and add thicker oil, but I'm not sure which oil. Maybe 6 or 7 K?

I'm thinking for my relatively mild temp operation, that the 10K might be a bit much.

Since my rad is also 15 years old, I'm going for a new all-metal one at the same time.

comments?

thanks

Dana
 
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Success!!!

UPDATE- I took the 10K filled clutch (left in pic), cleaned up the bimetal spring really good, pulled the end from the case (red arrow) and twisted it counter clockwise (looking down on it) just enough to where it didnt start the opening of the reservoir but about to, if that makes sense. I installed it and it works! Roar at start up and engagement when engine gets around 190 (a hair over half way on the modded temp gauge) and would cool to about 1/3 so it might be too much cooling I dont think the fluctuation is good is it?

So the later model clutches adjustable? Possibly with more research. I plan to experiment with the other clutch with spring tension and clutch in boiling water with meat thermo method to see if the actual opening temp is adjusted or if it is just returning to stock operation.
bP1040248.jpg
 
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UPDATE- I took the 10K filled clutch (left in pic), cleaned up the bimetal spring really good, pulled the end from the case (red arrow) and twisted it counter clockwise (looking down on it) just enough to where it didnt start the opening of the reservoir but about to, if that makes sense. I installed it and it works! Roar at start up and engagement when engine gets around 190 (a hair over half way on the modded temp gauge) and would cool to about 1/3 so it might be too much cooling I dont think the fluctuation is good is it?

So the later model clutches adjustable? Possibly with more research. I plan to experiment with the other clutch with spring tension and clutch in boiling water with meat thermo method to see if the actual opening temp is adjusted or if it is just returning to stock operation.


This is interesting. The old spring looks pretty dirty, you did a nice job cleaning it up. what did you use?

I gotta think that gunk/rust has to interfere with the operation of the spring, so maybe cleaning the spring should be part of a clutch overhaul.

Now, about the part where you adjusted the spring.... It looks like you "unwound" it a turn or so? Is that what you did?

Seems that would really mess up the clutch timing.

Dana
 

Cruiserdrew

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Dana-Over the years, it seems like cooling threads ALWAYS cycle back to needing a new radiator. Your fan clutch after almost 20 years probably is bad. Get a new one, problem solved. If you want to add higher cst fluid to it go ahead, but the rotating shaft inside the spring gets gunked up and prevents rotation, so no amount of fluid will provide better lock up.

I think you are on the right track with a new radiator, and it only makes sense to get a new fan clutch at the same time. Can't you just get the proper fan clutch for that motor from Australia?
 

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