3B/13B-T Fan Clutch and Fan Upgrade

3B/13B-T FAN CLUTCH UPGRADE

Onur

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I have been quite unhappy with the cooling performance of the tiny 3B/13B-T fan clutch and fan for quite some time.

As such, I did some research. I picked up a 1HZ/1HD-T fan clutch as well as the appropriate fan assembly. This fan clutch is the black-base FC.

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As you can see, it is a significant upgrade vs the stock 3B fan clutch-fan setup:

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Onur

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You can also see the significant size differences in the fan clutches as well:

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The fan shroud opening size is right at 18.75":

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You can see the sizing differences between the B iteration fan and the 1HZ/1HD-T iteration fan assembly:

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Onur

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The fan had to be trimmed about 1.75" to account for movement of the engine at idle and how the engine wants to move "forward" so to speak under WOT load. I trimmed about 1" first using metal snips. That took awhile. I was then able to "shape" so to speak, the fan blades on a bench grinder to get the curvature and sizing approximately correct. The key was to have enough gap between the shroud and the fan blade itself to accommodate movement between idle and WOT. This is key, otherwise, there will be some interference and you will damage the fan as well as the interior of the fan shroud.

At the same time, I took advantage of the fan shroud and radiator being out to install new upper and lower radiator hoses.

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Old ones removed:

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Fan size differences: 1HZ/1HD-T fan has one more fan blade (8) vs the 3B version (7):

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Onur

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At the same time, the PS idler pulley bearing was making lots of noises and I decided to swap the bearing out. The pulley assembly is discontinued from Toyota. Luckily, the 1FZ AC idler pulley (88440-26090) utilizes the same bearing:

Thanks to @cruiserdan for the lead on the bearing equation of the swap. A snap ring plier and a socket got the bearings out and was able to press the new one into the pulley in a bench vise.

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The above spacer is key in re-installation as it spaces the pulley out away from the bracket itself.
 

Onur

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In any event, I am about to drive down to NYC and will report back my temperature findings at both highway speeds and at idle in NYC traffic.

Currently, the fan clutch "howl" on start up stays on significantly longer (about 2 mins) before it goes away which is exactly what I wanted in that the fan clutch is engaging longer as needed. I'm excited to see a decrease in overall water temperature due to this upgrade.

Hope this helps someone in the future.

Best.
-onur
 
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Onur,
Very interesting that you have been seeing water high temps and your solution here to them. I have not had any high temp problems in my 3B even with turbo pulling near 10psi on the interstate in summer driving conditions. Watching and learning from you (which is not unusual). Please keep the details coming.

FYI Maybe I was pampered by radiator leaks soon after I got my 70 ... when I had the leaks repaired, the shop boiled/rod'ed out all passages for good water / heat transfer (rust acts like an insulator which reduces heat transfer).
 

Onur

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I should state: this is applicable to my 3B in a JDM BJ70.

3B’s received different fan clutch/fan combos in different markets and platforms.

Measure stuff before just going out and buying parts that might not work.
 
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@beno a question I have is that in FJ models with B engines what is the best way to reduce the distance from the water pump to radiator? Just installed a fan clutch and fan and new shroud, but there is about a 15 inches from the back of the rad to fan.

Whats the best way to get center on the shroud? The engine seems to sit lower than the center of the rad, so the fan doesn't line up quite right.

I guess I could modify the shroud and machine a spacer for the clutch?
 
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Very interesting mod, i may attempt it myself one day, thank you for sharing.
Any updates, is everything working as it should ?
 

Hugh Heifer

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Only reason to do this.
I only ask because you said you would report back about findings after the NYC trip and did not see you do so. Was curious if it met expectations, especially in stop and go traffic.
 

jblueridge

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I am probably going to do this upgrade.
Thanks Onur for posting such good instructions.

My BJ74 fan shroud is different from yours: mine has a lip on the engine side.
Did you modify your shroud to accommodate the larger fan and/or improve flow?
Mine is 2nd pic below.
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Onur

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I am probably going to do this upgrade.
Thanks Onur for posting such good instructions.

My BJ74 fan shroud is different from yours: mine has a lip on the engine side.
Did you modify your shroud to accommodate the larger fan and/or improve flow?
Mine is 2nd pic below.
View attachment 2281970

View attachment 2281971
I cut that entire lip off that is there on your second picture. To accommodate for the engine moving under WOT, I bent the upper portion of the fan shroud up a bit.
 
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