XJ was Overheating

[kirksjeep]

It all started last week before I left for my trip.  I noticed the radiator cap was leaking a little and was leaving some white residue on the air box.  Last Wednesday I was driving home and noticed a very strong coolant smell.  I pulled over and the radiator cap was off and sitting in the fender well.  Coolant was all over the engine bay.  I put the cap back on, drove a little further until I could get to a store and buy some water to get me home.  After I filled the Jeep up with water, I started driving again and just before I turned into my driveway the cap let loose again and I just parked it.  That night I went out and bought a new radiator cap and filled the radiator back up. 

Today I was driving to work and about 20 minutes into my drive the temp gage starts going up.  I pulled into Dunkin Donuts to get a coffee and as soon as I shut the engine off, the cap released a bunch of stream (but it stayed on).  I limped it to work and shut it off at the first parking lot after the gate and walked to work.  Later I went and bought some more water, filled it up and drove it home on the back roads, it was fine, never over heated, the temp gage stayed right at 210.   

The only things I could think of was a bad thermostat or an air bubble.  I pulled the thermostat and it looked ok.  I replaced it anyway and took extra care to burp the system.  When I was done I let it idle for 20 minutes, and even took it for a few mile drive with the AC on.  The temp with the AC on was just a little below 210.  Hopefully, the problem is fixed. 

[BlacXJeep]

When I first bought mine something simmilar happened. I overheated on my way home from RI. So I put water in just like you did, but then it never did it again. I think it had something to do with the jeep sitting for so long before I got it. Did your XJ sit?

[calvynandhobbs]

It could be that the sensor for the electric fan is not functioning properly. Cherokees have a mechanical fan that runs all the time as well as an electric fan that only comes on when it gets to a certain temperature. I had to hard wire mine with a switch on the dash because mine wouldn't come on at all. It never affected it while driving, but in stop and go traffic it would overheat.

[PaulW]

check the radiator itself.  when i bought my 1991 xj it had 210k on the clock.  it would overheat on the highway, and blow the cap off.  in traffic it was fine when the fans were coming on.  it turned out to be that the radiator had rotted out.  the fins between the cores were non-existent.the individual rows were there but due to the non existent fins, the truck would over heat on the highway.  as soon as the fans cam on then it was all good.

[kirksjeep]

Did your XJ sit?

From what I could tell about the Jeep from the titile, it was driven about 600 miles between last December and when I bought it in June, so it probabaly sat some.  The strang thing is that I have been driving it for a while and it just happened.

[kirksjeep]

check the radiator itself.  

The radiator has been replaced at some point.  I can tell it's not the  OEM one, and doesn't look that old.  The water pump has also been replaced at some point.  I have heard that the fan clutch can go bad and cause problems at highway speeds, so I'm going to keep an eye on that.  I drained the radiator since I had added so much water and the coolant came out a light brown color.  I didn't expect it to look nice and green, but I also didn't expect it to look as bad as it did since I had just drained the radiator and refilled it a few weeks ago. 

If it happens again, I think I might flush the system in-case there is a blockage some where.  I'll also change out the fan clutch, I hear they are only like $40 and hard to diagnose as the problem, but it happens enough to make it worth it.  I have used the prestone radiator flush system that taps into the heater hose, but do you think I should use the radiator flush chemical?

[PaulW]

check the radiator itself.  

The radiator has been replaced at some point.  I can tell it's not the  OEM one, and doesn't look that old.  The water pump has also been replaced at some point.  I have heard that the fan clutch can go bad and cause problems at highway speeds, so I'm going to keep an eye on that.  I drained the radiator since I had added so much water and the coolant came out a light brown color.  I didn't expect it to look nice and green, but I also didn't expect it to look as bad as it did since I had just drained the radiator and refilled it a few weeks ago. 

If it happens again, I think I might flush the system in-case there is a blockage some where.  I'll also change out the fan clutch, I hear they are only like $40 and hard to diagnose as the problem, but it happens enough to make it worth it.  I have used the prestone radiator flush system that taps into the heater hose, but do you think I should use the radiator flush chemical?

If the water that came out looked like rust, then I would absolutly use the flush chemical.  put it it the cooling system and run the truck for a good 15 miles to get it nice and hot.  then let it cool down and go to town with the garden hose.  it will help in the long run to get all of that poop out of your cooling system.  check to see if you have a block drain also.  all of the"debris" inside the cooling system usually sits inside the block.

[kirksjeep]

As I walked by the bucket of old coolant this morning, it looked more orange than rusty and that when I remebered I added Orange coolant instead of green after the cap blew off.  I didn't find any rust or debris at the bottom of the bucket, so I am guessing it is ok. 

[PaulW]

As I walked by the bucket of old coolant this morning, it looked more orange than rusty and that when I remebered I added Orange coolant instead of green after the cap blew off.  I didn't find any rust or debris at the bottom of the bucket, so I am guessing it is ok. 

good to know.  the other thing i would check for is a head gasket concern then.  you can get a block tester cheap at almost any auto parts store.  it goes into the radiator and detects exhaust gasses through a chemical process.  it's worth trying just to make sure you really don't have a big problem.

[kirksjeep]

As I walked by the bucket of old coolant this morning, it looked more orange than rusty and that when I remebered I added Orange coolant instead of green after the cap blew off.  I didn't find any rust or debris at the bottom of the bucket, so I am guessing it is ok. 

good to know.  the other thing i would check for is a head gasket concern then.  you can get a block tester cheap at almost any auto parts store.  it goes into the radiator and detects exhaust gasses through a chemical process.  it's worth trying just to make sure you really don't have a big problem.

If I have any more problems I'll look into that.  The 00-06 heads are know for cracking between the 3rd and 4th cyclinders, so I have been checking for the normal signs.  The 2000 are the worst by far and have something like a 85% failure rate.  The other years are all less then 10%. 

[reptile610]

As I walked by the bucket of old coolant this morning, it looked more orange than rusty and that when I remebered I added Orange coolant instead of green after the cap blew off.  I didn't find any rust or debris at the bottom of the bucket, so I am guessing it is ok. 

good to know.  the other thing i would check for is a head gasket concern then.  you can get a block tester cheap at almost any auto parts store.  it goes into the radiator and detects exhaust gasses through a chemical process.  it's worth trying just to make sure you really don't have a big problem.

If I have any more problems I'll look into that.  The 00-06 heads are know for cracking between the 3rd and 4th cyclinders, so I have been checking for the normal signs.  The 2000 are the worst by far and have something like a 85% failure rate.  The other years are all less then 10%. 

uh oh. 

[PaulW]

As I walked by the bucket of old coolant this morning, it looked more orange than rusty and that when I remebered I added Orange coolant instead of green after the cap blew off.  I didn't find any rust or debris at the bottom of the bucket, so I am guessing it is ok. 

good to know.  the other thing i would check for is a head gasket concern then.  you can get a block tester cheap at almost any auto parts store.  it goes into the radiator and detects exhaust gasses through a chemical process.  it's worth trying just to make sure you really don't have a big problem.

If I have any more problems I'll look into that.  The 00-06 heads are know for cracking between the 3rd and 4th cyclinders, so I have been checking for the normal signs.  The 2000 are the worst by far and have something like a 85% failure rate.  The other years are all less then 10%. 

espically on a higher mileage vehicle.  the leak down/block tester should be part of the annual tune-up.