DIY - Fan Clutch Refill/Rebuild Procedure..

[BnvS]

Fellow Mudders? Is there a DIY procedure on how to get your fan clutch refilled/rebuilt? my LC has 180k and T100 400k and both fans run a little bit after shutting the engine off. Like on the T100 at least 5 more times in hot 90 deg weather.. I'll update what the LC does in terms of spin.

I will also update the before and after temperatures of the coolant and AC temps... to see if it makes any difference. BTW the T100 goes up to 196 deg in 90 deg heat with AC on...The LC iirc does 195-197 deg with AC on

Anyways the procedure must be simple. Easier said than done..

Pre work if you really want to be careful (get a cardboard the size of the radiator to protect the inside of the radiator from your tool slippage that can damage the inside radiator fins (i did this install the timing belt)

1. Take loosen up the 4 fan clutch bolts
2. Take only the fan out if you can. Not likely so take it out with the shroud.
3. Take the Fan clutch out off the fan assembly
4. The the screws out of the Fan clutch (may need an impact screwdriver if the screws are really stubborn)
5. Slowly use a flat head to release the sides of the fan clutch.

Now here's the part I do not know.. so if anyone can help that would be great.

My questions are - are all questions I do not know and would like to figure out if there is any reference out there I can use..

1. How do I remove the old liquid in full?
2. How do I fill it?
3. Which side do I need to fill it?
4. How much ml/fl oz do i need to fill?

BTW I am going to use RC 10000 CST silicone fluid which is like less than half the price of Toyota recommended fluid (the Toyota recommended fluid is 08816-10001 for 10000 cst)
Something similar to the following liquid - RC 10000 cst Silicone Diff Fluid

 

[3_puppies]

for the price of a new Aisin fan clutch, I just replace them.
just my opinion

 

[Battleship]

Over in the 80 section, I think @landtank has a write up on clutch fluid replacement. How to adjust, open, drain, and a discussion on viscosity of replacement fluid.

Blue fan clutch mod...Thread has gone to hell, read at your own risk

History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...

forum.ih8mud.com

 

[BnvS]

for the price of a new Aisin fan clutch, I just replace them.
just my opinion

So I looked at the pricing of the Aisan fan clutches... Since I need to do 2.. I was not inclined to spend $70+ dollars for each on an Aisan brand.. now other ones are cheaper but not sure of their reliability. Those I saw cost between $35-50..

The take out replace clutch with silicone will cost me $10... also its good learning experience if it works or not and lastly saves the environment...of another part going into junk...

 

[JunkCrzr89]

So I looked at the pricing of the Aisan fan clutches... Since I need to do 2.. I was not inclined to spend $70+ dollars for each on an Aisan brand.. now other ones are cheaper but not sure of their reliability. Those I saw cost between $35-50..

The take out replace clutch with silicone will cost me $10... also its good learning experience if it works or not and lastly saves the environment...of another part going into junk...

If you live in a hot environment, a new fan clutch, regardless of whether it’s Aisin or not, will be insufficient. Even a new Aisin is often under filled with just 3k. Draining it and filling with a sufficient amount of 10k will make a major difference. The thread that @Battleship posted is the ticket. The differences between 80 and 100 clutches are minor.

 

[Godwin]

So I looked at the pricing of the Aisan fan clutches... Since I need to do 2.. I was not inclined to spend $70+ dollars for each on an Aisan brand.. now other ones are cheaper but not sure of their reliability. Those I saw cost between $35-50..

The take out replace clutch with silicone will cost me $10... also its good learning experience if it works or not and lastly saves the environment...of another part going into junk...

A Vessel impact driver with the correct JIS screwdriver bits make the job of removing the screws to split the fan clutch halves easy. I have this one 2500 - https://www.vesseltools.com/handtools/screwdrivers/impact/2500-detail but I see that it's now discontinued.

 

[saucebox]

Over in the 80 section, I think @landtank has a write up on clutch fluid replacement. How to adjust, open, drain, and a discussion on viscosity of replacement fluid.

Blue fan clutch mod...Thread has gone to hell, read at your own risk

History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...

forum.ih8mud.com

Yep, that's the same one I followed. Began with a new clutch, swapped to 15K. Absolutely roars at startup and on taking off from a stoplight, and I'm sure it's cost a few decimal places in MPG, but I don't have trouble with heat.

 

[BnvS]

@saucebox You're all the up to 15k cst? Dang. That's cool

 

[Biga27110]

Yep, that's the same one I followed. Began with a new clutch, swapped to 15K. Absolutely roars at startup and on taking off from a stoplight, and I'm sure it's cost a few decimal places in MPG, but I don't have trouble with heat.

I love that roar maybe i should do this 🤔

It would technically help with getting air through the ac condenser at idle as well hmmm.

 

[saucebox]

@saucebox You're all the up to 15k cst? Dang. That's cool

Haha, yeah. I was trying for something like 12K, but couldn't find any local shops that carried enough different fluids to make my own mix.

 

[yj668]

If you live in a hot environment, a new fan clutch, regardless of whether it’s Aisin or not, will be insufficient. Even a new Aisin is often under filled with just 3k. Draining it and filling with a sufficient amount of 10k will make a major difference. The thread that @Battleship posted is the ticket. The differences between 80 and 100 clutches are minor.

What's a good CST for 25-115F?

 

[JunkCrzr89]

What's a good CST for 25-115F?

@Somebodyelse5 could tell you. FWIW, temps where I live range from -10*F to 100*F and I put 10k in mine.

 

[ClassyJalopy]

Mine is just stock Aisin blue and it roars gloriously at start up and on take offs. Now I am paranoid...

 

[BullElk]

What's a good CST for 25-115F?

I’ve just replaced the fan in my Hundys but in my 80 series, in the past, I would mix 10k and 20k together. I think it’s all I had at the time. I’m in a stinky hot and humid climate,

 

[yj668]

I'll probably do 10K for now and see if I need better cooling.

I'm running 91 Octane, probably E10-15 (its CA). ~184-194F on a hot summer noon. Closer to 194F with the AC on.

 

[BullElk]

~184-194F on a hot summer noon. Closer to 194F with the AC on.

Huh? Why do you need to to do anything? You're not going to get better coolant temps than that.

 

[abuck99]

I’ve done this mod a couple times.

Drain clutch over night- I put 150watt spot lamp over the end of the clutch to passively heat it to get the fluid to flow. Try and measure the fluid removed- they are generally underfilled.

15k CST silicone fluid works well in a daily driver that also sees offroad duty. 20k CST may be a tad better for Arizona hot type weather. I’ve tried both and prefer the 15k.

Fill amount about 45-50ml just shy of a whole bottle (59ml). Too much fluid or too thick CST and your fan will stay hooked up longer (or all together) and chew fuel mileage and generally rob engine power.

Also- check and reset the valve opening temperature- this make s a difference when your clutch starts to shear fluid- sooner vs later, it’s explained in that 80series blue clutch thread.

Last- if the coil spring on front is corroded, or rusty and you have more than 100-150k miles on that clutch-just replace it. You can do the clutch mod to a new clutch which I have done. Fwiw the fan clutch bracket and clutch are suggested to be replaced together as they wear out close to same interval-( according to Denso).

 

[abuck99]

 

[yj668]

Huh? Why do you need to to do anything? You're not going to get better coolant temps than that.

Am I not missing out on something? 🤪 Oil in the clutch is the 23 year old factory fill.

 

[BullElk]

Am I not missing out on something? 🤪 Oil in the clutch is the 23 year old factory fill.

If you’re running 194* max, the only thing you’re missing out on is an overheating engine.