How to tell the radiator fan clutch, aka liquid coupling, is good or bad? (1 Viewer)

[peacesells63]

TB/WP was done with Aisin parts 2 years ago at 199K. Denso radiator installed last month. Toyota t-stat installed 2 days ago (old none-oe one was about 30K miles old).

I just started watching the coolant temperature recently, after the radiator popped out the top seal on my trip to MD. Comparing to my other MDX, I noticed the LX tended to run at about 10~15 degree higher coolant temperature under similar weather, which concerned me . I saw those close to 220 temperature during 110+ degree days, maybe that's why. Did see 220+ several times but it was under 115+ degree with AC on 4L climbing a steep slope.




I believe you are right and all these tests could only conclude a working but may not fully functioning (therefore weak) clutch.

Guess I will keep close watching of the cooling performance during the July 4th long weekend trip, and would most likely replace the clutch after that.


Sounds like a fun scientific experiment. Since the clutch has to be removed, I will probably just replace it with new one and leave the test to my daughter

Another thing, replace the plastic heater t's if you haven't already.

 

[KliersLC]

Blue fan clutch mod...Thread has gone to hell, read at your own risk

History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...

forum.ih8mud.com

Instructions are in that thread if you are so inclined. FWIW, the Arizona folks tend to use 15k or above fluid in the 80 series.

 

[KliersLC]

I'm sure someone mods 100 series, but IMO its not necessary on the 100 like it is the 80. The cooling system is way larger and radiator has much more surface area than the 80 series, so the stock fan oil works much better than the stock oil in a blue hub 80 series fan. 80 series is a fairly fine line between the fan engaging on the highway and running hot on the trail.

Maybe so, but modding a functioning fan clutch that is weak vs buying a new one......kinda the same thing.

 

[gregnash]

Ok lots of good info here now so that thing I would possibly suggest is if this truck is meant to be a crawler/wheeler and you are doing so in higher temps it might be worth while to throw a secondary cooling fan on the rad (in front) that you can manually switch on/off to help push air.

Outside of that, if the fan clutch hasn't been replaced recently (like with tb/wp) then it may be time. When I first bought my truck everything was fine. Went to a club meeting and guys were talking about fan clutches going out and how that is one of the things they all had done first and foremost on just about any vehicle that they purchased (used older vehicle that is) and low and behold that night I noticed mine started roaring. Took a bit to snake it out once I got the Aisin replacement but things have been great since.

 

[peacesells63]

Ok lots of good info here now so that thing I would possibly suggest is if this truck is meant to be a crawler/wheeler and you are doing so in higher temps it might be worth while to throw a secondary cooling fan on the rad (in front) that you can manually switch on/off to help push air.

Outside of that, if the fan clutch hasn't been replaced recently (like with tb/wp) then it may be time. When I first bought my truck everything was fine. Went to a club meeting and guys were talking about fan clutches going out and how that is one of the things they all had done first and foremost on just about any vehicle that they purchased (used older vehicle that is) and low and behold that night I noticed mine started roaring. Took a bit to snake it out once I got the Aisin replacement but things have been great since.

Pusher fans don’t do a whole lot, especially if they are mounted in front of the ac condenser. Land cruiser Phil sells a kit to add a factory fan to the later 100 series that didn’t come with them, they definitely help keep the ac cold when idling, but that’s it. As long as the fan clutch and rest of the cooling system is fully functional, should'nt have problems in PHX heat. Hopefully nobody is wheeling at 3pm @120f for the fun of it though, because that’s not fun...

 

[peacesells63]

Maybe so, but modding a functioning fan clutch that is weak vs buying a new one......kinda the same thing.

You can definitely do that, but I would split it and make sure the thermostat is functioning properly first. Even if the shaft seal is weaping a bit, you can play with silicone weights and the tstat setting if you like tinkering with stuff. Takes a long time for the fluid to leak out.

 

[AFei]

So many great info. Thanks everyone for the knowledge sharing.

Another thing, replace the plastic heater t's if you haven't already.

Looking at the history, the heater tees was replaced at 173K by PO. However, done by Jiffy Lube, along with radiator and other cooling parts, which is a concern to me, since that poor radiator didn't lost for more than 30K miles!

Any metal option of that plastic tee?

Outside of that, if the fan clutch hasn't been replaced recently (like with tb/wp) then it may be time.

Yeah, don't think it's ever replaced. Now I think it's the time to do so as PM.

Hopefully nobody is wheeling at 3pm @120f for the fun of it though, because that’s not fun...

I did it to test the cooling system. Not really wheeling although, a local hill in south mountain area

Blue fan clutch mod...Thread has gone to hell, read at your own risk

History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...

forum.ih8mud.com

Instructions are in that thread if you are so inclined. FWIW, the Arizona folks tend to use 15k or above fluid in the 80 series.

Thanks! Will definitely check it out.

 

[gregnash]

Yeah at this point, might as well for peace of mind!