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  #1  
Old August 11th, 2017, 15:11
cgross220 cgross220 is offline
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Strange overheating problem

So I've had my 2000 XJ (4.0L Auto) for about 2 months now and while I love it I'm afraid I've got a bit of a lemon. Earlier this week "Check Gauges" light came on for a bit, but all gauges seemed normal and the light quickly went off. However, when on the highway today the light came on and I noticed my water temp was almost pinned to 260. Almost right as that happened, I started to notice white steam coming from the hood near the taillight on the passengers side. I quickly pulled over and noticed my coolant was low, so filled it up with some warm distilled water from a gas station. I also noticed there was a good bit of liquid up near the battery, that I thought was coming from the top radiator hose. I was able to get to an O'Reilly's and pick up a new top hose and some clamps. With the old hose off though, I didn't see any cracks or leaks on the radiator or the hose side. Got the new hose on, put the car and park, no leaks at idle (though I didn't see any leaks at idle when I pulled over at first). Brought it to about 2k (just in park) and had no drips under the jeep and no overheating. Good, right? Nope. Pulled out, drove about 2 blocks down and got the same "Check Gauges", high water temp, and white steam. This time I started to look all over, and noticed that the A/C coolant line (at least I'm pretty sure that's what it is) was soaked right near that pancake-looking joint right under the top radiator hose. I should also mention that my A/C went out about a week beforehand, and while I bought freon with some UV dye to see what was going on I hadn't recharged the system and the A/C has been kept off all week. I dried off the area around the radiator and don't see any place for a leak on the radiator, but am baffled as to 1) why an A/C leak would be causing the gauge to read high or for the engine to actually be overheating, 2) why it JUST started if the A/C hasn't been working for a week, and 3) why it's not leaking anything when parked or at idle but seems like it's POURING out when driving. Any help would be appreciated. Thanks
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  #2  
Old August 11th, 2017, 15:18
Slimer Slimer is offline
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Re: Strange overheating problem

Welcome Club XJ. I don't know what to tell you, I am having overheating issues also. I finally gave up and ordered the most expensive radiator and waterpump that I could get. We will see if throwing money at the problem fixes it. I have replaced everything else.
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  #3  
Old August 11th, 2017, 15:52
cgross220 cgross220 is offline
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Re: Strange overheating problem

Well dang that's not comforting haha. Guess I'll just start pulling parts off and seeing if I can find a crack in the radiator I didn't see before or something.
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  #4  
Old August 12th, 2017, 07:12
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Tim_MN Tim_MN is offline
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Re: Strange overheating problem

If the Check Gauges comes on and the temperature is higher than about 220*, and/or there is coolant leakage, you need to find and fix the problems. The A/C not running is seperate and unrelated problem. Google Jeep 0331 head cracking and research why fixing overheating problems are critical.

Overheating can be caused by anything that decreases the cooling system’s ability to absorb, transport, and dissipate heat, such as a low coolant level, loss of coolant (through internal or external leaks), poor heat conductivity inside the engine because of accumulated mineral deposits in the water jackets or radiator, a defective thermostat that doesn’t open, poor airflow through the radiator, a slipping mechanical fan clutch, an inoperative electric cooling fan, a collapsed lower radiator hose, an eroded or loose water pump impeller, leaky frost plugs, or even a defective radiator cap.

The cooling system is a group of related parts that depend on proper function from each of its component parts to keep the engine cool. Service the cooling system and replace any/all under-performing or suspected weak parts. Any component part of the cooling system that is not fully doing its job will stress the others, and your engine will overheat. Temperature creep on the 4x4 trails, at idle, or in stop-n-go traffic, points to a weak or failing mechanical fan clutch or worn out water pump fins.

The most important maintenance item is to flush and refill the coolant periodically. Coolant should be replaced every 36,000 miles, or every two to three years. Anti-freeze has a number of additives that are designed to prevent corrosion in the cooling system, but they have a limited life span. The corrosion causes scale that eventually builds up and begins to clog the thin flat tubes in the radiator and heater core, causing the engine to eventually overheat.

-Inspect/test or replace the mechanical fan clutch. A worn fan clutch will allow temperature creep at stoplights, in heavy traffic, and on the 4x4 trails. A fan clutch that “looks” OK is not the same as working OK.
-Inspect the electric cooling fan and the fan relay. Apply 12 volts and make sure the fan runs. Exchange the cooling fan relay with one of the others similar relays. Confirm that the e-fan starts when engine temps reach 215-218*. Repair or replace the fan or relay as needed.
-Inspect/test or replace the coolant temperature sensor that activates the e-fan.
-Replace the water pump. The pumping fins can deteriorate over time and the pump will not flow enough coolant to keep the temps under control.
-Inspect/replace the radiator hoses. Make sure the coiled wire is installed in the lower hose.
-Inspect all of the freeze plugs in the block and the ones on the backside of the head for rust holes and coolant leakage.
-Use a chemical flushing/cleaning solution to remove mineral buildup or rust, flush with clean water, and then drain and fill the radiator with a fresh 50/50 coolant and water mix. With neglected cooling system you may have to flush several times.
-Inspect the radiator for mud/bugs/grass clogging the outside and mineral deposits clogging the inside. Clean or replace as needed.
-Replace the thermostat with a genuine Jeep 195* thermostat. Cheap thermostats are cheap for a reason.
-Replace the radiator cap if your Jeep has one. An old worn out radiator cap will allow not hold system pressure which can cause boil overs and/or allow the coolant flash over into to steam. You will likely see the coolant temps suddenly jump from 210* to the Red Zone and back to 210* if your radiator cap is weak.


If you have covered all the points listed above and still have overheating issues, inspect and test the head for cracks and head gasket for leaks. Exhaust gasses entering the coolant can raise the temperature of the coolant or cause steam pockets in the coolant that will temporarily block the flow of coolant.


Read more about cooling systems here –
www.offroaders.com/tech/engine-overheating.htm
www.carparts.com/classroom/coolingsystem.htm
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Last edited by Tim_MN; August 12th, 2017 at 07:19.
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  #5  
Old August 12th, 2017, 09:52
cgross220 cgross220 is offline
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Re: Strange overheating problem

It's not a cracked head, oil is clean and there's no water out of the exhaust when hot. And I'm definitely not gonna drive it without coolant or anything, I cracked the heads in my '72 Chevelle and don't want to go through that again. The main thing I was poking for with the A/C was an off chance that somehow the freon leak was causing the high temp gauge to misread seeing as I cannot find a coolant leak otherwise. When at idle, the Jeep leaks nothing. Even at park with the engine revved there are zero leaks. I flushed the coolant system like a week after I got the Jeep and had the system tested at JiffyLube and everything was perfect. Guess I'll go through your list to check over the radiator, shit I'd be happy if it just took a new radiator and I'd be good to go but something is telling me it's not gonna be that easy

Last edited by cgross220; August 12th, 2017 at 09:56.
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  #6  
Old August 12th, 2017, 12:48
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Ecomike Ecomike is offline
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Re: Strange overheating problem

Not much left to add after that awesome post... except to go rent (free loaner) a radiator pressure tester and use it to pressure test the entire cooling system to see if it holds pressure at the test gauge, if not, keep the pressure up and look for the leak source over about 30 minutes, it will show up 95% of the time.

Also T-stats typically go bad when the engine is overheated to 260 F or higher. If it was any good to begin with. So you may have 2-3 problems now.

AC has nothing to do with the leak. Sounds like it might have been a heater hose leaking near the AC compressor. Photos would help, but they must be shared here from another site to display. Google "Jeep Chreokee 2000 engine images" for some edited photos here and there to identify part names. Thingamabobs and whatchamacallits or not useful names for us, LOL.

Replace the radiator cap right away, they are cheap. Make sure the entire jeep is full of coolant, by leaving the Radiator cap off till the coolant visibly flows in the radiator. That happens once the T-Stat opens, to confirm the engine and radiator are full of coolant.

Check the engine oil for white goo, signs of coolant in the oil.

And its not a lemon, its a JEEP, Just Empty Every Pocket. :-)

Good luck and welcome to !!! What part of Texas are you in?

Quote:
Originally Posted by cgross220 View Post
So I've had my 2000 XJ (4.0L Auto) for about 2 months now and while I love it I'm afraid I've got a bit of a lemon. Earlier this week "Check Gauges" light came on for a bit, but all gauges seemed normal and the light quickly went off. However, when on the highway today the light came on and I noticed my water temp was almost pinned to 260. Almost right as that happened, I started to notice white steam coming from the hood near the taillight on the passengers side. I quickly pulled over and noticed my coolant was low, so filled it up with some warm distilled water from a gas station. I also noticed there was a good bit of liquid up near the battery, that I thought was coming from the top radiator hose. I was able to get to an O'Reilly's and pick up a new top hose and some clamps. With the old hose off though, I didn't see any cracks or leaks on the radiator or the hose side. Got the new hose on, put the car and park, no leaks at idle (though I didn't see any leaks at idle when I pulled over at first). Brought it to about 2k (just in park) and had no drips under the jeep and no overheating. Good, right? Nope. Pulled out, drove about 2 blocks down and got the same "Check Gauges", high water temp, and white steam. This time I started to look all over, and noticed that the A/C coolant line (at least I'm pretty sure that's what it is) was soaked right near that pancake-looking joint right under the top radiator hose. I should also mention that my A/C went out about a week beforehand, and while I bought freon with some UV dye to see what was going on I hadn't recharged the system and the A/C has been kept off all week. I dried off the area around the radiator and don't see any place for a leak on the radiator, but am baffled as to 1) why an A/C leak would be causing the gauge to read high or for the engine to actually be overheating, 2) why it JUST started if the A/C hasn't been working for a week, and 3) why it's not leaking anything when parked or at idle but seems like it's POURING out when driving. Any help would be appreciated. Thanks
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091

Last edited by Ecomike; August 12th, 2017 at 12:57.
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  #7  
Old August 12th, 2017, 12:56
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Ecomike Ecomike is offline
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Re: Strange overheating problem

So it only leaks when you drive it?

Check the heater hoses that run from the front of the engine, next to the AC compressor and back to the firewall.

A cheap (like $20) infrared temp tester from harbor freight is a gold mine for tracking down hot and cold spots everywhere under the hood that are awesome clues to where and what is too hot, and what is too cold (and thus not working). And you can verify that the Temp sensor is good or bad with it!!!

Sad to say though, it might be a head gasket leak raising the coolant pressure under load and leaking exhaust gas into the coolant system.

But it is way too early to conclude that.

Quote:
Originally Posted by cgross220 View Post
It's not a cracked head, oil is clean and there's no water out of the exhaust when hot. And I'm definitely not gonna drive it without coolant or anything, I cracked the heads in my '72 Chevelle and don't want to go through that again. The main thing I was poking for with the A/C was an off chance that somehow the freon leak was causing the high temp gauge to misread seeing as I cannot find a coolant leak otherwise. When at idle, the Jeep leaks nothing. Even at park with the engine revved there are zero leaks. I flushed the coolant system like a week after I got the Jeep and had the system tested at JiffyLube and everything was perfect. Guess I'll go through your list to check over the radiator, shit I'd be happy if it just took a new radiator and I'd be good to go but something is telling me it's not gonna be that easy
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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