BluJay

Hey y'all,

I wanted to reach out here before making any final decision a re-manufactured.

It's a 98 Cherokee 4.0 I6 4x4 forest package with about 220k. It was a CA state truck before I got it.

My cherokee has been overheating in the red on me when stationary for a longer than stop light period of time. It's not just the dash going off; the overflow bottle is boiling when the light comes on. It runs hot @about 220-230 when around town it has a 195 thermostat.

I have already replaced my radiator last year to a 3 row due to a leak and since the first overheating I have replaced the water pump, radiator cap, thermostat & housing, upper and lower hose and did a power flush. The electric fan turns on automatically and with A/C and is strong. The engine fan is tight and does not spin freely when you try move with hand.

I also got a test kit for finding exhaust in the radiator fluid and the color did not change to indicate a head gasket leak...

So i'm not sure what else it could be. I thought about trying a kool flow water pump or removing the thermostat but I'd rather fix it right if I can.

It does leak oil from about every gasket, has the high speed wobble and front end popping noise/feel when braking going forward only. Just encase it gives any influence on cooling issue.

Appreciate any input you may have.

Crash_Course

Do you have good airflow through your AC condenser or is it blocked up, preventing air from getting to your radiator?

InitialForce

X2 on checking for blockages on your AC condenser and radiator. Put a light on one side and look at the other side.

BTW the coolant test kits you can buy at an auto parts store are useless... there has to be a massive leak for them to detect anything. Take it to a shop that has a sniff meter (and one that doesn't try to rape you for all your money) and have it tested properly if you suspect a head gasket failure.

Does it overheat even with the AC off or just with the AC on?

Have you verified opening temperature of the thermostat? I have seen quite a few in my time that don't open where they are supposed to

Az93xj

I did the test kit on mine too. I idled it for fifteen minutes while testing and it kept passing too. After fifteen minutes it started spewing water violently for about thirty seconds. After it calmed down I ran another test and sure enough it failed almost right away. Pulled the head off in about three hours last night.

Firestorm500

Either you have a blown head gasket, and/or your head is bad on your Jeep.

With the miles and oil leaks, either the whole engine needs to come out and be rebuilt, or you need to sell the Jeep.

This is about the mileage where you see a lot of non-wrecked Cherokees in salvage yards.

Fred/N0AZZ

My 99 4.0/AW4 has 226,000 on them and both still run strong with good compression. When I first bought it saw a weep hole in the radiator so replaced it along with the complete cooling system all stock from AutoZone water pump, fan clutch, fan, belts, thermostat and housing, hose's. It has never overheated once even on the trails driving very slow in 4L with AC on.


I would say do a compression check on your engine first to see what your working with, if they are all close then proceed. Next oil leaks it may look like its leaking everywhere but may be only a few very easy fix's. First pressure wash the engine top to bottom laying on the ground to get to the bottom and clean off all the old oil. Drive it as little as possible to where you park overnight on concrete so you can see more easily where the oil drips.


You will find most all oil leaks come from 3 places either the oil filter adapter O-rings, Dist. gasket or Valve Cover gasket. All of these run to the rear of the engine and many think it is a rear main seal which it is not. These are very common and happen on a large percentage of all XJ's mine included.


Check these first and also never remove the thermostat, come back and tell us what you find.

VTJeep

Could you elaborate on that point for me? Thanks!

Fred/N0AZZ

That can cause more heating problems with the increased flow/not enough time in radiator to cool.

Turbo X_J

1. Takes forever for the engine to reach operating temperature.
2. The thermostat, popular opinion aside, has absolutely nothing to do with the maximum engine coolant temperature.

VTJeep

Oh, like delete it. Not where my head was at. I was thinking like removing it to replace

BluJay

I plan to run up to checkers and get another thermostat tomorrow, its too late after work to check for blockage but will look tomorrow.

It did overheat 3 times today on way to work, with and without A/C.

However it was overheating when climbing, passing and accelerating. When letting off the gas mostly and coasting it the temps would fall back down. Again the o/f bottle threw up.

Firestorm500

Classic signs of a blown head gasket and/or cracked head.

Fred/N0AZZ

Both of which are easy to check for with a leak down tester that can be borrowed from AutoZone with a deposit. Good idea to eliminate that as a cause before going further.

BluJay

Well I did take get that tester and it was negative, I mentioned that in the first post; perhaps you missed it.

I also verified today that there are no blockages or debris around the fans or radiators.
I took it out today to two auto zones to get the gasket and thermostat. It stayed around 210 with ac on.

Replaced the thermostat with fail-safe one, old one looks in OK condition.

I also did spray out the engine bay today, looks like valve cover gasket for sure and some tbd.











Will take to work later and see whats up. Thanks for all your input.

InitialForce

Make sure you boil test that thing before you put it in.

Edit:
Nvm, misread your post. You can boil check the old one though and see if it was working or not