Yesterday I took a couple of mud holes mostly dirt water. After the second hole i parked my unlimited jk. when I started the jeep again I noticed that it was starting to overheat, it reached more than 3/4. We noticed that the fan was not working. A friend cleaned it up, tapped it and sprayed with WD40. After that we returned home with no issue. Is this common in these Jks.? Need advice...

 

Been there done that. Mud got caked in the fan shroud, your fan couldn't turn when it wanted to turn on and the stuck fan fried your motor and fan switch or something or other. Your JK will stay cool when you drive around, but not at idle. Turn on the JK and wait for the fan to turn on; it won't. It'll cost you $500; not covered under warranty because they'll find mud caked in hard to reach crevices and consider it abuse. Since they might flag you, I'd advise fixing it yourself. Also, it's an easy fix. All they do is install a new fan assembly and plug it in. Shoulda done it myself.

You might've also fried some a/c something or other, which is what happened with me. That was covered under warranty for some reason though.

 

too much mud(dirty water) in the rad won't help but no fan is definatly a problem.

you only need the fan when stopped or moving slowly, so I would still check and see if it comes on.

I've had my fan stay on when it should have shut off(-40 and driving) but never had it not come on.

 

spartan has the right idea.. these fan motors burn up REAL easy..... chrysler did not put any over-current sensing into the computer so typically the motor burns up before it blows the 60 amp fuse in the TIPM box if you cake it with mud (or snow)... argh!!!

a circuit breaker could probably be wired in so that the fan motor (when the rotor is locked) would be cut off until such time as you could get it cleaned up.....

you likely didnt destroy your air-conditioner as there is supposed to be a high pressure cut off switch to kick off the A/C in event of no fan / high pressure..

spartan may have had a bad High pressure switch - this why is A/C was covered under warranty...

-Christopher

 

Interesting, I wonder if it's a too large of fuse? I may have to break out my inline ammeter (plugs into the fuse and reads the highest spike & constant draw) and see what the fan actually draws, wouldn't be a bad idea to put a breaker on it.

 

Can the fuse be downgraded?

 

im not sure if you can downgrade it.. my guess is that it is set up for starting surge current if the fan starts in high speed....

technically the fan should always start in low then go to high but reality is if the jeep hot soaks... (you drive it on a really hot day.. shut if off for just a short time).. when it is restarted the engine temp is higher than when you shut it off so the fan will go right into high for a few seconds... then back off to low...

I dont know all of the logistics but when my 08 kept burning up fans it was also blowing 60 amp fuses and causing the SES light to come on... in my case somehow the computer was commanding both low and high speed according to the final report before the jeep went back to chrysler from the lemon case....

to truly determine what fuse is needed you would need to take the spike start current.. or CAREFULLY check the locked rotor current..

chrysler claimed up and down that the fan was protected by the TIPM and would not be destroyed due to locked rotor situations... nor would it be destroyed due to low and high being commanded by the PCM...

at one point after I lost the 4th fan (and that jeep never even saw a gravel road.. let alone mud).. i went into one of the dealers that worked on mine right after it was supposedly "repaired".. popped the hood.. started the jeep.. we watched the fan for a bit saw it go form low to high.. it made a wierd sound.. so we shut it off.. he got his meter out after i said over current protection is not present.. he claimed it was.. we got into a bit of a match.. I restarted the jeep, hit the A/C, grabbed the fan and held it stopped.. (yes I had gloves on... yes I grabbed it before it had a chance to start spinning) we both stood in awe as the motor burned up.. THEN the 60 amp fuse in the TIPM box Popped(not sure if thats the fuse directly for the fan or if that fuse is other stuff too)..... replaced the fuse and the fan spun at about 1/3 speed for maybe 2 minutes..smoked and stopped.. that was the end of the motor... technically they couldve charged me for that motor.. but they didnt.. and we both learned something...

since I havent had any issues with my 2009 i never looked any more into breakering that fan circuit but knowing that there have been many that lose fans due to caked mud under the hood and how much it costs to fix.. it might be a good idea to come up with...

in my opinion for a jeep that gets wheeled in the mud a belt driven fan shouldve been an option... granted i like electric fans for their low engine RPM prowess in keeping the A/C condenser cooler (im all about my A/C).. but if I was into mudding Like I used to be I would fashion up a shroud and a belt driven fan....
-Christopher

 

Have you noticed the water pump pulley has a threaded shaft for a viscous fan drive?

 

Not a bad idea. I have read of quite a few fans burning up. A simple resetable pushbutton breaker in the power line would certainly make sure it never happens again. Do you have an inline current meter that can handle more than 10 Amps? If not, let me know and I can check it out with my high current clamp and an oscilliscope.

 

sure have... id have to look at a TJ again to see if the water pump rotational direction is the same... if it is.. might be possible to do...

I dont plan on mudding my current jeep so ill likely never do it myself.. but its sure an idea for those that do a lot of mud / water runs....

I think one of the biggest issues is that the electric fan stops completely when the engine is cool and A/C is off...

so that as you wheel mud gets up in there and has a chance to build up before the fan tries to come on... then when it does we know the rest....

a spot of advice might be to use the air-conditioner even if you dont particularly want it.. because it will run the fan more often keeping it free from excess buildup...

-Christopher