fan clutch (1 Viewer)

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Taz

Joined
Mar 27, 2003
Threads
56
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Location
Gallatin Gateway, MT
At what temp should the fan clutch start to kick in?

I did the glove test on my NEW (blue) fan clutch today and I was able to stop it fairly easy. Engine temp was about 190 and I had just run the truck for about 20 mins.
 
In cooler weather I turn the a/c on Max, open the doors then slow the fan, keep stopping it, let it "windmill", slow or stop it again, reducing the airflow by not letting it get to top speed. In a few minutes it will take off and you won't be able to stop it, very noticeable, much louder. They kick in on the far side of 200F. This is a project on our list, the blue hub clutches are adjustable for kick in temp and we are looking for a source for thicker oil so they "lock" tighter for our hot Arizona summers.
 
Kevin, do you know what the Toyota factory fill fan clutch oil viscosity is?
 
Do you know how much silicone fluid is in a new clutch, or is that where you are stuck?
 
I'm in the same boat Rich.

My truck was at normal operating temp and I was able to stop it with no resistance!
 
Rich said:
Do you know how much silicone fluid is in a new clutch, or is that where you are stuck?

That's one of the specs we are looking for, you want enough to work and a little reserve, but too much and it won't release. Most of the bad clutches we have are full of oil, so the theory is that the silicone oil breaks down, no longer causing the shearing action that drives the fan. Replacing it would restore the original performance and thicker oil may transfer more torque to the fan improving performance in desert areas.
 
UltraFJ said:
I'm in the same boat Rich.

My truck was at normal operating temp and I was able to stop it with no resistance!

That's how they work, get it a little hotter than normal and it will kick in if it's good. How old is it, blue hub type?
 
One way that comes to mind to arrive at a fill amount would be to start with either a new, or a presumed leak free clutch. On a suffciently accurate scale weigh the clutch. Open it up, drain out what you can, clean out the rest. Weigh the clutch again. Now you can derive by weight the factory fill amount.
 

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