so it was 105 today...

rghouse

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yep, you guessed it, the old 92 started overheating again waiting in line at Costco for gas. Had to switch the A/C off, the electric fan on, and step on the gas to over 1500 RPMs. Thought I had it licked finally, but its been a mild summer...

Mod'd fan clutch: check
complete cooling system overhual: check
top-end rebuilt: check

Only thing is the thermostat is not OEM, and I have an OEM radiator (been removed and fully flushed/inspected). Heard something about putting a fancy diesel rad in a 3FE so maybe I'll try that next. Open to suggestions. :bang::doh:

the FC does not roar like an airplane (green hub) with heavy weight fluid in it despite what the crowd says but it is better. main symptom is stuttering like its low on water. It did drink about 12oz of water between costco and sportsmans warehouse (Ammo was no prob since my address matches btw, CA guys). Also, for some reason the interior fan/AC stays on when the ignition is shut off until the door is opened, a totlaly separate issue but i just noticed this recently when its really hot outside, and just now when temp creeped up.
 
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the green fan clutch is set to open right at 125 F ( I have 2 of them to play with, and i had verified with my thermostat) the target temperature is 95 F per Landtank's blue fan clutch mod. And yes, the Green hub 3fe Aisin hub is adjustable from factory. Even with thicker oil, the motor will most likely overheat before the the fan clutch is fully opened from factory setting. I have also adjusted the timing to open @ 100-105 F and have seen significant improvement over stock timing plus 20k oil. What was your temperature at idle when you turned on heat? Mine use to go up to about 210 F on slow wheeling even without AC on a 100F + day. After adjusting the clutch to open @ 100F, i can idle with AC till the gas runs out and will never break 196F Without AC, my aftermarket gauge sits at 187f all day on idle.
 
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Fan clutch "needs to roar" on start up and in hot weather or its not working properly

104 here as well today...heard FC roar on start up and after awhile when AC was on and going down HWY 80 into sac....
 

rghouse

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Marco, I advanced it last time it was out (to add more RC car gear oil) but im not sure how far or at what temp. will investigate

I just use the stock gauge and watch it like a hawk. It went from (edit) 3 oclock to 2 oclock in 1-2 minutes and I responded
 
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I would just buy a new Aisin Green hub from Amazon, about $120. Drain and add 45ml of 20-30k fluid in, adjust the timing to open 15- 20F earlier, 95f to be exact. Install and report back with your result. If you are overheating at idle, most likely your fan clutch timing is off, if you are overheating on highway, perhaps your radiator.
 

rghouse

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Highway is fine. Hub is only 1-2 years old. I'll just pull it again and drive my truck. Super Duty fan clutches work great...
 
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Marco, I advanced it last time it was out (to add more RC car gear oil) but im not sure how far or at what temp. will investigate

I just use the stock gauge and watch it like a hawk. It went from 9 oclock to 10 oclock in 1-2 minutes and I responded
I would add a KOSO aftermarket gauge on the upper radiator neck. The stock gauge sits in the middle from 150F to 225F, at 10am position, you are 235F plus and rising fast...
 

LINUS

Waiting for the Great Pumpkin
 
 
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Marco, I advanced it last time it was out (to add more RC car gear oil).....

I just use the stock gauge and watch it like a hawk.
Since not a later cluster / maybe not Raventai mod to the resistor is possible, since we know the cluster gauge has a “deadhead zone” - what about adding a good aftermarket temp gauge?

Esp since you have modded the fan clutch, and anything ***could*** happen like leaked out RC oil, viscosity breakdown, etc.

Just my armchair QB suggestion, I’d want a good gauge or a OBD2 scangauge/dongle to phone - to get accurate numbers. Since no OBD2, a dedicated gauge seems like smart money.
 

96FZJ80

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How's the condition of the radiator cap? Mine would start to heat up at idle (I do a lot of idling in 100 degree heat for work) and modding the original Eaton fan clutch didn't help. Radiator cap was in bad shape so replaced it with a new one from the auto parts store (topped up the radiator as I was obviously low) and now everything is good - haven't even seen 200 on the Ultra-Gauge since.
 

rghouse

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I would add a KOSO aftermarket gauge on the upper radiator neck. The stock gauge sits in the middle from 150F to 225F, at 10am position, you are 235F plus and rising fast...
can I use a union and tap into a rubber line, or is tapping the metal somewhere preferred? Seems like tapping the metal would be better. Amazon has these blue unions that would be easier, less stressful/invasive, anybody used these? If so what diameter
1565970850127.png


in regards to timing FC I recall seeing methods using an immersion bath with a thermometer. Is that still the prefferd method or can I just tighten the screw some more? I'll have to replace all fluid if I do the bath, would rather not
 
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I'll have to replace all fluid if I do the bath, would rather not
With the blue hub, which should be the same, you don't get water inside the hub and shouldn't have to change the silicone fluid after adjusting the timing if you are careful. I put a vege basket in a boiler and used a candy thermometer when I did mine and it worked well. The basket kept the clutch off of the bottom of the boiler where it may have seen higher temps than the water and the candy thermometer can be clipped on and set at whatever depth you want in the water.
 
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can I use a union and tap into a rubber line, or is tapping the metal somewhere preferred? Seems like tapping the metal would be better. Amazon has these blue unions that would be easier, less stressful/invasive, anybody used these? If so what diameter
View attachment 2059774

in regards to timing FC I recall seeing methods using an immersion bath with a thermometer. Is that still the prefferd method or can I just tighten the screw some more? I'll have to replace all fluid if I do the bath, would rather not
Here is a pic of how mine is done.


I use a 38-40mm adaptor from amazon with 1/8" NPT for the koso water temp sender. 40mm fits better IMO, but both will work. Koso comes with a 1/8" Bsp thread, but i would recommand using thread sealant and a correct size o-ring for it. Been running this setup for 2 yrs and wheel it in hot climate with no problem, Koso gauge works flawlessly.
As for the timing of the fan clutch, take picture of the orientation of the 2 screws and set it in 1-2" of water on a small pan and heat up to 110f and set it on a wood chopping block and let the temp. cools down to about 100-95 and loosen the screws and rotate. The target temp. is about 95-100f and the final screws orientation should be closer to the center slot position. I use a real time digital thermostat from Amazon. Detailed write-up is below from Landtank. Good luck. I would test the stock fan clutch setting and take note on the temperature for when the plate starts to open and compared with your target 95-100f. I found both of my green hub was set to 125f to open from factory.
Here is a pic of the green hub with factory setting, (notice the orientation of factory screws position on the slots)

Blue fan clutch mod
 

Tools R Us

 
 
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The old F motors have two gaskets on the thermostat, one for the flange and one ring type at the top of the thermostat. This is unusual, so the top gasket is often left out, or can fail, causing some coolant to bypass the radiator, unexpected cooling issues. Some have chased their tail, done lots of work, and $$$, only to find the problem was a simple gasket. On them it's good to confirm both gaskets are in place.

Tstat_o-ring.jpg
 
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