Fan Clutch Mod

I did this mod 2 years ago, but waited to get some time behind the wheel to see if I liked it. There is also very little info about this on TW, so I though I'd share.

The process is very simple: Paint mark one fin top & bottom, remove phillips screws to split fan clutch in two, add a bottle of Toyota 10K CST fan clutch fluid (08861-10001) & match marked fins to re-assemble.



This mod will make the fan clutch hit harder at idle and scenarios like stop & go traffic (yes, the wind blowing is louder, but that's the point). It is mainly for people in hot climates or you can do this mod to give some life back to an old fan clutch.

My fan clutch still functions normally and disengages after the rpm goes up, it just hits harder at idle & take-off.

https://youtu.be/zfw_udDcUgM

 

Interesting, wonder what the viscosity of the stock fluid is?

 

Unless you are changing the thermo-couple inside the fan, all this does is remove the cushioning of the stock fluid and creates a harsher engagement. I don't think that extra bump is worth it considering the bearing for the fan clutch is the water pump bearing. More than likely you are just going to kill the water-pump faster than you would without the fluid mod.

 

I believe it is 6k fluid

FJ40/60/80 guys have been doing this for decades without issue.

 

It's just increasing the drag in the clutch thus making the fan turn faster when it is disengaged.
Until fuel economy started becoming a thing we didn't have fan clutches, fan's were essentially turning 1 to 1 with the pulley all the time rather than basically free wheeling until temps get high.

We have the fan clutches locked out on all of our tractors that have them because otherwise they tend to run hot in our Texas heat.

I may try it, the A/Cs in these need all the help they can get when it's 100+ out especially with a double cab.

 

We had some members in the CSF radiator thread do this as well, some years ago. Never any negative effects mentioned, that I remember.

 

Thanks for that input! Nice to know there are more with the same experience. I have run my fan clutch like this for 2 years before posting about it.