Guys, my '97 XJ AW4 has been running pretty nicely lately. We can drive highways, even up grades in the heat without overheating. The electric fan kicks on when its supposed to.

But. When we have to climb a hill on a dirt/gravel road, it will overheat. I'm not sure what else to try. I do notice the electric fan looks a little wimpy in its rotating.

Any ideas what we can to do improve cooling performance when climbing these dirt roads without a lot of speed for airflow???

 

The OEM cooling system when it's in top shape works very good. Don't know what all you've tried but your cooling system is probably due for a overhaul. Basically if you don't know the age of the component replace it.

 

Sounds like a failing fan clutch. I was having similar problems with mine, and there was almost no resistance in the fan clutch when spun by hand. A popular upgrade is using the fan clutch from a v8 jeep grand cherokee, which is what I used. Should be able to search the site for a proper part number, I don't have it handy.

 

Replace the viscous fan clutch, and if you don't already have one, install an auxiliary transmission cooler. In your conditions, the torque converter lock-up clutch is probably not locking the the torque converter most of the time (during loose dirt climbs) and that can lead to very hot transmission fluid, which shares cooling with the engine coolant in the radiator. So a very hot transmission can contribute to higher engine/coolant temperature.

 

Low speed overheating is typically caused by an airflow issue such as a bad fan clutch, worn or not working efan, or clogged up radiator or ac condenser fins. Judging by what you are describing I'd guess fan clutch as well as stated above.

 

When my electric fan cut in it sounds like a tornado. I would suspect yours is ready to be replaced. Probably the bearings are worn.

 

"I'm not sure what else to try."

Still wondering what he's already tried?

 

Hello bad-*** super people of cherokee forum.

I am confident the mech fan/clutch are good -- I replaced the clutch not too long ago, and it whirls like heck when engaged. The shroud is in place.

The electric fan, though, seems very weak and wobbly. you can kind of see it going backandforth as well as roundandround.

So, I'm thinking replace electric fan and look at doing the transmission cooler job, as those two don't sound very tough.

I'm pretty sick of having to pull over 2 or three times on a 6 mile drive to wait for the coolant to stop boiling

I'm hoping "When my electric fan cut in it sounds like a tornado. I would suspect yours is ready to be replaced. Probably the bearings are worn." is true! Mine sounds nothing like a tornado... a cat purring perhaps :P

I did a cooling system flush about 2 years ago... maybe that is in order also (fluid looks clean though). I replaced the water pump about 2 months ago because the new one from Napa was leaking already (they did not stand behind their product, btw).

Long and short:
Thing | Confidence
===================
Mech Fan | High
Elec Fan | Low
Radiator | Mid
Rad Cap | High
Hoses | High
Overflow | High
WP | High

 

Replacement fans from Rock Auto aren't that expensive.

 

clutch fan ...........

 

If the electric fan turns on with the AC and turns on when coolant temps reach about 212 then even though it may be wobbling a little bit (and should probably be replaced anyhow because of that) I would say that electric fan is doing what it needs to do. as u/jordan96xj mentioned I would install an auxiliary cooler for the AT as the road you are describing is very taxing on the AT and could be raising temps.

If the E-fan and Cooler don't remedy the problem I would start looking at the potential for a blown head gasket as it sounds like you've eliminated all other possibilities.

 

Confident its not the head gasket, because in my (admittedly limited) experience, that will cause overheating during normal operation as well. Also don't see any of the classic signs (milky oil, burnt material in coolant, gysering coolant when starting engine with rad cap off).

Definitely not the fan clutch: that was replaced recently. Mech. fan is working well.

Going to replace elec. fan with direct fit from Oreilly's (I've got a $10 off at Oreilly's

Hope and pray that will cut the cheese.

If not... consider options, AT cooler being top of list.

 

Recent replacement means nothing anymore. I've gotten brand new parts out of the box that were bad or failed within a month or two, and then gotten parts from the same place, same brand that are still going to this day. It's a total crap shoot.

 

So true
On the back of this post I tested my mech fan because I had replaced it a couple of months ago and overheated in traffic since.
I went to the Jeep when cold, span the fan by hand to test the resistance. Started the Jeep, waited for the temp to come up and the electric fan to kick on. Stopped the engine, and span the mech fan by hand again. No Difference!
Looks like that one is going back :/

 

Alright, Dave1123 gets the beer on this one.

Replaced electric fan yesterday, and that afternoon the Jeep sailed right up the 6 miles of dirst/rock track -- no overheating.

The new fan does indeed sound like a tornado. It looks about 4 times more powerful than my old one.

Thanks, all!