Aisin FCT-049 fan clutch (1 Viewer)

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I’ve not changed my fluid, but I do wish I had a little bit more engagement at idle.

I don’t overheat, but it’s really hot here in Texas.
 
It's that time of year again.

@Godwin @HemiAlex @John McVicker do any of you have update on the fan clutch oil mod? I'm ordering some 20000CST oil today. I have the original fan clutch (I think FCT-017, red if I recall correctly) in storage and figured I'd open it up and mod it, then swap it in place of the FCT-049 I've had installed for a few years.

So I did a little extra reading on this today. Found a fairly decent explanation of the screw "settings" on this page:

Seems Godwin was on the right path to tuning the FC to lock up earlier than the stock setting.


Based on this info from the above link...
View attachment 3352181


I took a closer look at Godwin's photos from the first page.

Initial "stock" setting, we can see that the valve would be closed over the outer hole in the rings (the 0 position from the above graphic) View attachment 3352185





When he moved the screws to the right, it appears the valve would be partially open especially at the outer hole located at the rings, akin to the A position from the graphic. I would assume this would allow for an earlier lockup given the same oil weight.
View attachment 3352187

I've done nothing more in trying to adjust the fan clutch. Became too busy last year and did not have the time. I was planning on setting the open fan clutch in a shallow pan of water and raising the temp to test at what temp the clutch would begin to open. I may come back to this later this summer when we begin to have hot temps.
 
I'm bumping this thread to add that I have nothing to add. When I started this thread last year I was seeing higher than expected engine temps, 210 instead of 195 and decided to tweak the fan clutch. Two weeks ago Texas kindly shared their heat bubble with Alabama and our daytime temps rose into the high 90s. I made an 8 hour interstate run on one of these days. I was expecting to again see engine temps approaching 210 but the temp held at 195-200, and running I think the standard fan clutch. IOW, I have no good idea why my 2F was running hotter than normal last year and does not seem to be doing so this year.
 
I installed the 20k oil last week and adjusted the valve screws to about 2/3 to the right. Definitely an improvement, it’s been crazy hot here (105-110) and over the weekend I did some of the longest steepest inclines in AZ and didn’t hit 230 so that’s a win. I think I need to reposition the valve screws to about the 1/2 way spot to keep the fan from coming on under 200 deg… I could tell it was locked up even around 185 or so.

I posted a short vid on IG - I did a little viscosity test on the stock green hub oil and figure its about 5k weight. So the 20k is quite noticeable.
 
My truck only gets warm sitting at idle with the ac running at 750rpm

It will hit 210* like that with 105* Heat index

If I bump the idle to 1200 rpm with the hand throttle it’s fine. If I know I have to sit, and my wife or dogs are in the car I’ll leave it sitting like that. The fan kicks on hard right above idle.
 

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