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Thread: How to service your tired FZJ80 fan clutch.

  1. #1
    Join Date
    Aug 2011
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    Alamo City, TX
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    Default How to service your tired FZJ80 fan clutch.

    Tools that are required for the job.
    12mm wrench. I used a 12 point but read that a 6 point will reduce your chances of rounding the nuts.
    Vice Grips. These are for when you round the nuts.
    10 and 12mm ratchet sockets.
    T25 star driver.
    Can of man.


    The first thing that you will want to do when attacking this job is to let the engine cool. If you are impatient, like me you will burn your arms on the valve cover.

    Second you will need to take off the 4 nuts that hold the fan clutch on. Using two 12mm would be the easiest, I used a wrench and vice grips. On this step I managed to round off two of the 4 nuts, which complicated my life, but I got over it. I used my can of man and vice grips and got the buggers off.

    Third you will need to take out the top two bolts on the fan shroud, I think mine is aftermarket, so you may have more or less bolts than I did.

    Next you will take the assembly out, and unbolt the fan from the clutch.

    This is after it was already out











    Here I used the T25 star driver and pulled the 4 bolts out that are holding the two halves together.

    Once the bolts are out you have to pull hard on the two pieces and they will come apart. From here you set one half one something and let it drain overnight.





    In the morning you will refill with CST fluid. I purchased a 15k viscosity, I can't remember who told me to get that but I have seen recommendations for 10 and 15k. It can be purchased from your local hobby shop, it's RC diff fluid. I put 30ml back in, Cleaned the fan and put everything back together. It now pushes much more air through than it did previously. I will be getting an ultraguage to get some actual engine temps.

    It really is a very simple job, easier than the dizzy o-ring in my book. Just make sure that you have the time to drain it and fill it properly.
    For to Marines, love of liberty is not an empty phrase… Rather it’s displayed by blood, sweat and tears for the fallen.
    -General James "Mad Dog" Mattis

  2. #2
    Join Date
    Apr 2009
    Location
    Dayton, OH
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    Great write-up just in time for summer temps!

    For the last 2-3 years, I have changed out the oil (15K) every 12-18 months in my OEM blue hub fan clutch to insure optimal performance. It may be slightly over-kill, but it keeps the system in good shape and those engine temps in check.

    This is one thing any 80 Series owner should take the time to perform.
    Pete

    Expedition Vehicle in constant flux...97' FZJ80 40th - 285K

  3. #3
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    Alamo City, TX
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    I figured it was definitely time to do mine because I would grab the fan and stop it while the engine was running. (not something I recommend) What kind of temperatures are you reporting with this done?
    For to Marines, love of liberty is not an empty phrase… Rather it’s displayed by blood, sweat and tears for the fallen.
    -General James "Mad Dog" Mattis

  4. #4
    Join Date
    Apr 2009
    Location
    Dayton, OH
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    No..I never recommend grab the fan...nevertheless it is a good test.

    As far as observed temperatures via my ScanGauge II. I generally see at highway speeds 188-193* during the warmer months (above 50* ambient) and at stops the temps creep up to 191-195*, occasionally 197*.
    Pete

    Expedition Vehicle in constant flux...97' FZJ80 40th - 285K

  5. #5
    Join Date
    Oct 2011
    Location
    Bartlesville, OK
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    91
    Thanks for writing this one up. I've been contemplating buying a new version with the oil already changed but may tackle this one myself.

    I learned about 12 point versus 6 point when changing the UCA bolt on my FJC. 4 hours of hack-sawing later it was off.
    2013 Toyota Tacoma DC
    2006 Toyota Land Cruiser
    2012 Ford F-150 - Sold (Giant POS)
    1997 LX450 - "The Krackin" - Sold
    2008 FJC - "The Batmobile" - Sold

  6. #6
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    No problem, It was very very easy. The fluid cost $8, and the modded one is over $200. That made my decision for me. Best of luck!
    For to Marines, love of liberty is not an empty phrase… Rather it’s displayed by blood, sweat and tears for the fallen.
    -General James "Mad Dog" Mattis

  7. #7
    Join Date
    Oct 2011
    Location
    Bartlesville, OK
    Posts
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    That's exactly what I needed to hear. Now get a Scangauge or Ultragauge and post up some temps!

    My current temps are 186-194 normal driving in 80F or less.
    Driving on the trail they have been up to 203 F which isn't crazy but is much higher than I'd like.
    2013 Toyota Tacoma DC
    2006 Toyota Land Cruiser
    2012 Ford F-150 - Sold (Giant POS)
    1997 LX450 - "The Krackin" - Sold
    2008 FJC - "The Batmobile" - Sold

  8. #8
    Join Date
    Jun 2010
    Location
    Flagpole
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    2,394
    Why do numbers over 200 scare everyone...I was under the impression that the computer has the ac turn off at temps greater than 217...but that the engine can handle much higher temps
    I would think a normal operating cooling system can handle higher temps...I know there is all this doom and dread out there about 1fzfe head gaskets...I don't obsess over my scanguage and pucker my anoose when temps approach or exceed 200...

    FWIW I overhauled my cooling system last year...new radiator...new fan clutch w/o oil swap...PHH...etc...
    Scangauge shows normal 190-195 but often pushes 210 on the long grades here at altitude in the warmest months of the summer...


    BTW nice writeup

  9. #9
    Join Date
    Oct 2011
    Location
    Bartlesville, OK
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    Quote Originally Posted by Flagster View Post
    Why do numbers over 200 scare everyone...I was under the impression that the computer has the ac turn off at temps greater than 217...but that the engine can handle much higher temps
    I would think a normal operating cooling system can handle higher temps...I know there is all this doom and dread out there about 1fzfe head gaskets...I don't obsess over my scanguage and pucker my anoose when temps approach or exceed 200...

    FWIW I overhauled my cooling system last year...new radiator...new fan clutch w/o oil swap...PHH...etc...
    Scangauge shows normal 190-195 but often pushes 210 on the long grades here at altitude in the warmest months of the summer...


    BTW nice writeup
    The way I see it, the optimal engine temp is 180-200 as per the majority of people running around town. Since the head and block are made of two different metals they expand at different rates, often causing issues with the head gasket. I'd rather keep my temps in control to avoid any issues and prolong the life of the engine versus the alternative.

    One less thing to worry about
    2013 Toyota Tacoma DC
    2006 Toyota Land Cruiser
    2012 Ford F-150 - Sold (Giant POS)
    1997 LX450 - "The Krackin" - Sold
    2008 FJC - "The Batmobile" - Sold

  10. #10
    Join Date
    Aug 2011
    Location
    Alamo City, TX
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    1,008
    Here is a little update on the fan clutch...
    I checke it today to see how it was doing. It felt like it was pushing hardly any air and I saw cst fluid on the fan. So now I believe I have a known bad fan clutch that has drained the fluid out of itself twice.

    Now the decision. $40 replacement from rockauto, or $230 dollar replacement for landtanks modded fan clutch. What say yee?

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