offroading --> overheating --> broken A/C ??

Richard in Georgia · **Posted:** Mon Jun 28, 2010 10:24 am

The local rock crawler team (Revolution Offroad, out of Augusta, GA) took me along to the Durhamtown Plantation 4x4 trails over the weekend. Of the 10 or so vehicles in the convoy, 8 were stripped Toyotas with at least 6" of lift, 37" boggers, etc... Needless to say my 3" lifted Libby had to fight, but I was able to keep up on almost every trail. Jeep > all

Towards the end of the day, my "Transmission Temperature" warning light came on the I noticed that the temperature gauge was redlining. I shut off the engine, opened the hood, and checked the oil for any signs of coolant in case I blew a gasket. Finding nothing, I drove the Libby back to the pro shop and washed off pretty well, making sure to get all the mud from the radiator.

PROBLEM: On the drive home, every time I turned the A/C on, the temperature gauge began to redline, and eventually the A/C lost all traces of cold air. I would vent the engine bay by turning the heat on in the cab (in the middle of summer!! - now that's love) every so often, but nothing else except the A/C would cause this problem.

Obviously I've broken my air conditioning system, but does anyone have an idea of what happened or the cost to fix? Thanks!

ATXKJ · **Posted:** Mon Jun 28, 2010 10:32 am

I would double and triple check the mud in the radiator and AC condenser - remember the Aluminum fins are thin - too much pressure will bent the fins

JL Rockies · **Posted:** Mon Jun 28, 2010 11:18 am

.... and mud can ruin the condenser fan quick... my sentence in FL taught me that. :evil:

tjkj2002 · **Posted:** Mon Jun 28, 2010 10:19 pm

Were you in 4low on the trail? If not that was one of your issues.

Richard in Georgia · **Posted:** Tue Jun 29, 2010 8:38 am

tjkj2002 wrote:

Were you in 4low on the trail? If not that was one of your issues.

alternated between 4hi and 4lo, as necessary. how is that a problem?

tjkj2002 · **Posted:** Tue Jun 29, 2010 10:06 am

Richard in Georgia wrote:

tjkj2002 wrote:

Were you in 4low on the trail? If not that was one of your issues.

alternated between 4hi and 4lo, as necessary. how is that a problem?

4hi puts more stress on your trans and engine.When offroad just keep it in 4low and keep the speeds down and your trans should never overheat.

KJ's with the 42RLE seem to overheat the trans faster then the older KJ's with the 45RFE trans,the whole reason is the trans coolers used.

Oh and by the way get your trans fluid changed soon,just because it looks okay does not mean nothing,once it overheats it's life is severely reduced.

jnaut · **Posted:** Tue Jun 29, 2010 1:15 pm

I suspect your electric fan isn't turning on. That fan turns on when the AC kicks on for the extra cooling needed. My guess is your brushes or windings are full of mud/dust and causing it to stop turning as needed. And x2 on double checking any mud in the fins.

Richard in Georgia · **Posted:** Wed Jun 30, 2010 10:55 am

tjkj2002 wrote:

Richard in Georgia wrote:

tjkj2002 wrote:

Were you in 4low on the trail? If not that was one of your issues.

alternated between 4hi and 4lo, as necessary. how is that a problem?

4hi puts more stress on your trans and engine.When offroad just keep it in 4low and keep the speeds down and your trans should never overheat.

KJ's with the 42RLE seem to overheat the trans faster then the older KJ's with the 45RFE trans,the whole reason is the trans coolers used.

Oh and by the way get your trans fluid changed soon,just because it looks okay does not mean nothing,once it overheats it's life is severely reduced.

Trans fluid was changed the day of incident. I took a pressure washer to the radiator/condenser fins yesterday, just to make sure all the mud was cleared. Sure enough, the air blew cold, but only for about 10-15 minutes before the temp gauge began to creep towards "H" again. This leads me to believe that somewhere between the condenser and my vents, there's still some mud stuck somewhere.

MonsieurGlen · **Posted:** Thu Jul 01, 2010 12:33 am

You might also want to have your A/C system checked. Mine started doing that and is now only blowing hot air. 2 different well trusted garages told me it was the A/C compressor clutch. Cost for repairs: about $700-$800. The extra stress from a bad compressor clutch could also cause higher engine temps.

Richard in Georgia · **Posted:** Fri Jul 23, 2010 9:27 am

jnaut wrote:

I suspect your electric fan isn't turning on. That fan turns on when the AC kicks on for the extra cooling needed. My guess is your brushes or windings are full of mud/dust and causing it to stop turning as needed. And x2 on double checking any mud in the fins.

you were exactly right, it was the radiator fan assembly. got it replaced for $450.

STINGN · **Posted:** Fri Jul 23, 2010 11:21 am

Good thing you solved the problem

kskj · **Posted:** Fri Jul 23, 2010 6:25 pm

Richard in Georgia wrote:

jnaut wrote:

I suspect your electric fan isn't turning on. That fan turns on when the AC kicks on for the extra cooling needed. My guess is your brushes or windings are full of mud/dust and causing it to stop turning as needed. And x2 on double checking any mud in the fins.

you were exactly right, it was the radiator fan assembly. got it replaced for $450.

Wow $450. I have a Radiator fan motor and shroud for a 07 that I would of gave you.

offroading --> overheating --> broken A/C ??

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