Fan clutch test? FJ80/3FE

[roostabunny]

I'm in the middle of an overdue cooling system refresh (I'll post a pic thread for posterity when I'm done), and I was ready to do something with my green hub fan clutch (probably the rebuild with 10K CST that several folks have described).

Picture is only slightly related. Here's my victorious shot - hard part done - removing the water pump. Ignore the color on the flange, that's a reflection of the green tarp I pitched to keep the rain off me and Vera.

Anyway, when I got the fan out previous to this, the clutch looked in much better shape externally than I expected. Made me wonder if it'd been replaced in the past and was not the 223K-mile original.

It hasn't given me any trouble (aside from minor protest on removing it, but that's its own story), and seems to have good turning resistance (doesn't spin free). The bimetallic spring has a lot less rust/corrosion than I expected on an Alabama truck.

So, my noob question is... since I don't know the age of the part, I'm wondering if there's a way to bench-test the fan clutch, or, if there are reliable ways I can observe performance once I get it back together?

 

[SUMMIT CRUISERS]

The easiest known test is at a cold startup, the fan will roar for about 30 seconds or so. If not, the clutch is bad and either needs replacement or fluid drain/refill. I would drain and fill with 10k or 15k CST fluid and go with it. Dont try the newspaper or paper towel test on the fan. This could result in damage to the fan.

 

[roostabunny]

The easiest known test is at a cold startup, the fan will roar for about 30 seconds or so. If not, the clutch is bad and either needs replacement or fluid drain/refill. I would drain and fill with 10k or 15k CST fluid and go with it. Dont try the newspaper or paper towel test on the fan. This could result in damage to the fan.

I've read about the roar - so this is different from just the roar of wind from the fan itself?

No disrespect to anyone who's done it, but I wince at the thought of sticking anything in a spinning plastic fan with that much torque behind it - clutch or no. My paranoid brain assumes the result will be pieces missing from me, the fan, or both.

Now that I say that, I kind want to try it with a carrot and go viral with the video. LOL

I've got a local RC Shop source for 10,000 CST fluid, may try to pick some up on the way home.

 

[roostabunny]

BTW, I've read fill amounts from 1.25 to 2.5 oz, so if I walk away with more than that, I should be good for the procedure.

I don't believe it's intended to be a user-serviced assembly, but is there a spec anywhere for the amount needed in a green-hub clutch?

 

[SUMMIT CRUISERS]

I don't believe it's intended to be a user-serviced assembly, but is there a spec anywhere for the amount needed in a green-hub clutch?[/QUOTE]

I've used a 36 ml bottle for refill with positive results.

As far as the roar, the fan will be locked up and will produce lots of air until the clutch releases. It will also roar/lock up at idle, with AC running on 95 degree (estimate) and above days.

 

[roostabunny]

Finally finished up post-water-pump (and t-stat and hoses) re-assembly and what I started it up this time I totally heard the roar. Which is to say, I heard it stop after a few seconds. So, I think for now I'll keep it in there. Appreciate it!