2001 Wrangler overheating

A friend of mine has a 2001(?, it's the 2001 style, may be newer) Wrangler that overheats intermittently. It's mostly stock, just a 2" lift and 31" tires. It started while we were offroading and stuck in a creek that was almost up to the doors. It did it again ascending a muddy hill at WOT, and again after a slow descent down a long hill, after a full throttle climb on the other side. Those were the only times it did it while offroading. We didn't really think anything of it, since it was being used fairly hard. The next day he told me that it overheated on the highway while he was drving home.

We have decided it's one of three things:
1) The EGR is failing to turn on, this is what I'm leaning toward without having looked at it except on the trails.
2) The tranny is overheating, causing the radiator to get too hot, in turn overheating the engine. (but the fluid is bright red, and doesn't smell burnt)
3) The guage is wrong, although after pulling the rad. cap off after overheating and sitting for 20 min (we put a sweatshirt over it to protect from the steam), and over a gallon of coolant boiled off. Seems like it was much hotter than the 210 degrees that it normally runs at.

A faulty thermostat was also thrown in by a guy that was out there with us, but it seems like if it were the thermostat, it would overheat immediately after the initial warm-up.

Has anyone else had a similar problem? What was it? I'll probably be driving out to his place to take a look at it next weekend, and it's a 70 mile drive, so I'd like to know every possibility before I get there

Thanks-
-Jason

A friend of mine has a 2001(?, it's the 2001 style, may be newer) Wrangler that overheats intermittently. It's mostly stock, just a 2" lift and 31" tires. It started while we were offroading and stuck in a creek that was almost up to the doors. It did it again ascending a muddy hill at WOT, and again after a slow descent down a long hill, after a full throttle climb on the other side. Those were the only times it did it while offroading. We didn't really think anything of it, since it was being used fairly hard. The next day he told me that it overheated on the highway while he was drving home.

We have decided it's one of three things:
1) The EGR is failing to turn on, this is what I'm leaning toward without having looked at it except on the trails.
2) The tranny is overheating, causing the radiator to get too hot, in turn overheating the engine. (but the fluid is bright red, and doesn't smell burnt)
3) The guage is wrong, although after pulling the rad. cap off after overheating and sitting for 20 min (we put a sweatshirt over it to protect from the steam), and over a gallon of coolant boiled off. Seems like it was much hotter than the 210 degrees that it normally runs at.

A faulty thermostat was also thrown in by a guy that was out there with us, but it seems like if it were the thermostat, it would overheat immediately after the initial warm-up.

Has anyone else had a similar problem? What was it? I'll probably be driving out to his place to take a look at it next weekend, and it's a 70 mile drive, so I'd like to know every possibility before I get there

Thanks-
-Jason


I had similar problems with my 99 TJ. I replaced my stock radiator with a 3 row from radiatorbarn and have not been over 210 since. I also replaced my Fan Clutch.

If its an automatic yes the coolant runs into the radiator also. I added a deep tranny pan. But if I had it to do over would add an oil cooler when I had the radiator out.

HTH

I've had the same problem for over a year now. I have changed 2 thermostats, every hose clamp, two main hoses (top and bottom), the water pump, teflon taped the union in the hose to the tranny and checked for leaks everywhere. I learned a long time ago that an air bubble in the radiator will cause overheating. Every 100 miles or so, I have to top up the radiator, because the overflow is boiling off. After the pump change, it settled down, but still has overheated a couple times. All the overheating has gummed up my oil and caused a oil pressure problem. Once the engine gets to 210, the pressure will go to 0 when idling. I have to rev past 2100 rpms to "pump" the oil back up. I have heard that a slight crack in the head gasket might cause cylander pressure to build up in the radiator and cause boil off. I haven't tested this theory yet, because I haven't wanted to take the head off yet. I am at a loss, but I hope my thoughts will help you figure out your problem. Please let me know if you come up with anything.

TRAD,
have you tried replacing the radiator ? Stock radiators (at least my 99) has a plastic top and bottom that leak. I put in a 3 row for I think under $160 (to my door) and have been running good temps, even with a Warn 9.5ti covering it.

Does it matter what specifications for the radiator? I think the 2001 TJ requires at least 18psi to increase the boil point. Is that pressure requirement essential if I install an aftermarket radiator?

Trad ,
I have heard of fixes with just the radiator cap. You may want to go that route I think they are $3.00. Not sure if it will help or not but its worth a shot. Otherwise you may want to ask at jeepsunlimited.com there forum has an abundance of knowledge. (Probably too much at times)

This is a semi-common problem. The radiator is probably your issue, relpace it (upgrade it) and you will be much better off.

Thanks for all the input guys. Turned out it was the fan clutch. We replaced the thermostat too, just because it was cheap and we figured why not do it.