Before I do much trailering, I'm going to upgrade the cooling system to the Trailer Tow Package. I will likely end up at salvage yards, as buying new O.E.M. parts are way to pricy for me. Is there differences between years (mine is a 2005 3.7L) of KJ's? and just so I don't miss something, I want to make sure I am getting ALL the parts. from my understanding, I will need to find a H.D. fan shroud, the electric fan that resides in it, a fan clutch, and of course, the plastic fan that bolts to the clutch. are there more parts than this? // also, I have a question about the electric fan. my original fan is a 3 wire fan. and i have found out that they also made a 2 wire fan. are the H.D. electric fans 2 wire, 3 wire, or both depending on year or equipment?
Heavy Duty Cooling (Trailer Tow)
- Thread starter XWrench3
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uss2defiant
Full Access Member
I think you've accounted for everything.
some 2003 to early 2002 are 2 wire fan with speed controlled via PWM.
3 wire fan is low speed or high speed.
This is not dependent on the towing package.
as a side note, some 2003 to early 2002 with the 45RFE ****** had the in-radiator ****** cooler.
The switch to 42rle which is what you have, used a separate aux cooler for the ******.
some 2003 to early 2002 are 2 wire fan with speed controlled via PWM.
3 wire fan is low speed or high speed.
This is not dependent on the towing package.
as a side note, some 2003 to early 2002 with the 45RFE ****** had the in-radiator ****** cooler.
The switch to 42rle which is what you have, used a separate aux cooler for the ******.
is the stock trans cooler big enough for the extra heat of towing a trailer? the big problem i see is all the cooling goes thru the same stream of air. a/c condenser, trans cooler, (maybe engine oil cooler) and finally radiator. each adding heat and transferring it to the following cooler. if the left side of the engine bay wasn't so cluttered, i could add louvers on each side, and mount a cooler on each side (fenders). which would kill 3 birds with 1 stone. 1, get more air thru the engine bay, 2, move some of that additional heat load from the radiator, and 3, keep the engine bay dry (as opposed to louvers in the hood. i just do not feel comfortable with water dripping down on all those electronics.
uss2defiant
Full Access Member
Some old members like twobobsKj have changed their radiator to have the in radiator ****** cooler on top of the aux ****** cooler.
In-Radiator ****** Cooler AND Standalone? | Jeep KJ and KK Liberty Forum
I have no experience with louvers, tommudd might chime in about them.
In-Radiator ****** Cooler AND Standalone? | Jeep KJ and KK Liberty Forum
I have no experience with louvers, tommudd might chime in about them.
mercdudecbr600
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With the HD cooling system retrofitted, I think you'll be just fine. My 02 KJ has the towing package and even at idle in 100* days, no overheating.
I did add, though, another inline trans cooler even though my KJ came with the better trans. I mounted it to the front of the radiator just as a precautionary measure on towing, etc. during hot days.
I did add, though, another inline trans cooler even though my KJ came with the better trans. I mounted it to the front of the radiator just as a precautionary measure on towing, etc. during hot days.
JeepJeepster
Full Access Member
Cant answer the question on the 2 wire or 3 wire with the towing package. For whatever reason, my 04 came from the factory with the HD fan shroud and 2 speed fan, so all I needed to add was the fan clutch and fan blades.
I will say, the factory trans cooler is not up to the task of keeping the trans cool. Mine will quickly get over 210F when towing long distances. Not sure how much it weighed, but I recently towed a load of dirt that had me doing 40mph at WOT, it was not safe as it liked to wag a bit, but the trans was getting close to 250F and I had only been driving for ~20min. It had to be over 5,000lbs.
I will say, the factory trans cooler is not up to the task of keeping the trans cool. Mine will quickly get over 210F when towing long distances. Not sure how much it weighed, but I recently towed a load of dirt that had me doing 40mph at WOT, it was not safe as it liked to wag a bit, but the trans was getting close to 250F and I had only been driving for ~20min. It had to be over 5,000lbs.
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I just replaced the clutch fan on my ‘06 after 107,000.
My '06 with tow package came with a 2-wire fan, which is one speed only (no PWM and not speed controlled). The PCM grounds a relay to turn it on and, from what I've been able to determine, does so when either the coolant temp sensor (ECT) resistance goes below one set value or the aircon is engaged/the ECT goes below another value,
JeepJeepster
Full Access Member
Interesting... Wonder how the CFM matches up to the 2 speed fan.
