XJ607

my jeep over heats only when wheeling weather is ligh trails or heavy duty it over heats but does NOT over heat when on the road.. Gets VERY VERY hot any ideas? i checked all fluids and this isnt it.. any other ideas? seems like the floor maybe getting hot rather than motor... when i turn the heat on it is extremely hot also

djb383

"search" fan clutch and cooling system maintenance......go from there.

LawDog9

If that don't work install manuel on and off switch on fans and run them entire time ur wheeling.

freegdr

in stop an go and idle what happens

1976Mustang

What's happening is when you're wheeling, you're moving slowly or not moving at all. So the cooling is completely done by the fans alone, which then are most likely sucking hot air from the bottom of the engine back into the radiator. When you're driving, the speed you're going is forcing air into the radiator, and removing the old hot air.

I think it's about 40mph that you're fans are useless because the amount of air your trucks speed is forcing into the radiator exceeds the amount the fans are moving. So do as they said above, and try a Radiator flush as well.

XJ607

i already have it on a switch to turn it off and on.. and im installing a 180 thermostat and also do the radiator flush today... well see where that gets me.. the jeeps been off the road for a bit but ill let u know when i try this and go wheeling

djb383

If it does fine on the road, why would installing another t-stat make any difference.....t-stat only controls minimum temp. Fan clutch and fan shroud need to be functioning properly and in place when moving at slow speed for extended periods of time. If the rad is old, flushing it will probably do little to nothing. How old is the water pump?

XJ607

not sure about water pump.. bought the jeep off a buddy a year ago so at least a year..

pmichel

x2. Replace the fan clutch. Costs $36 at Autozone and takes 30 mins max.

sthon

Go with a ZJ NON HD fan clutch. I got one for a '98, it's a little bigger but runs at 60% rather than the stock XJ fan clutch at 40%. It's louder, so as long as you don't mind the extra noise it'll suck a lot more air at slow speeds.

djb383

.....and in addition to the extra noise, the big fan clutch will suck more gas and power away from the wheels. Don't guess about how old or what condition all of the various cooling system components are in. If u don't know, replace all of them. A big fan clutch is a weak band-aid for other failing cooling system components. Once all of the cooling system has been replaced and if it still gets a little toasty, while wheeling for extended periods of time, then add the big fan clutch.

sthon

If it does it's not noticeable, I would rather lose 1HP and .5MPG than overheat.. But hey, to each his own.

djb383

Did it overheat when it was new?.....and didn't have a big fan clutch? Again, do all the maintenance 1st and try the band-aid last.

sthon

That's kind of a stupid way of thinking. You upgrade everything else, axles, lift, tires, armor, etc. This adds weight, gears help but the already weak cooling system suffers.

88jee

Maybe fan clutch, I had similiar issue, this simple fix helped out a lot. I bet if you drove on the highway for an extened period of time it would start to overheat, at least thats what mine was doing. Also verify that it is really overheating with temp gun, sometimes its just that dumb sensor and you replace the whole cooling system just to find that out.