Coolant question

[Kimber6331]

Does anyone else have weird coolant behavior? Or am I missing something. I checked my coolant reservoir yesterday after my xj was parked for 48 hrs and there was pretty much nothing, which to me meant no coolant. (its been like that for a while and never had over temp problem. Is that weird?) anyway I bought some good stuff filled it up to the max line and put some straight into radiator bout an inch from top. Drove it rest of Sunday. After atleast 12 hours I checked it while engine was cold, fluids cold and my reservoir was already below add line. There's no coolant leak it's been in same spot since yesterday. Does it not flush back to reservoir like most vehicles or is there a problem here? Or like I said am I just missing something?

[XJ Wheeler]

Mysterious disappearing coolant is usually a sign of a head gasket leak/cracked head. Might check your oil? Are you sure there are no leaks? I have a leak on mine currently in one of the heater hoses and it seems to only drain the overflow. If you have an extra piece of cardboard you could lay it underneath the engine overnight.

[Kimber6331]

I'll have to check. i know i have a decent oil leak. but as far as coolant I didn't think I did. As far as being extremely low on coolant and not having overheating problems for months, is that considered normal? If I had that bad of a leak I would think that after 4-5 months there would be a serious issue/indication of some kind.

[4.3LXJ]

I would keep an eye on it and add more before jumping to conclusions.

[Mudderoy]

Does anyone else have weird coolant behavior? Or am I missing something. I checked my coolant reservoir yesterday after my xj was parked for 48 hrs and there was pretty much nothing, which to me meant no coolant. (its been like that for a while and never had over temp problem. Is that weird?) anyway I bought some good stuff filled it up to the max line and put some straight into radiator bout an inch from top. Drove it rest of Sunday. After atleast 12 hours I checked it while engine was cold, fluids cold and my reservoir was already below add line. There's no coolant leak it's been in same spot since yesterday. Does it not flush back to reservoir like most vehicles or is there a problem here? Or like I said am I just missing something?

I had a situation where the leak was so small it was getting the fins wet under the electric fan but I never saw any liquid on the ground. I just happened to but looking around the engine compartment with a flashlight and I noticed that the fins looked darker under the blades of the electric fan.

Then I knew the answer to why my coolant was disappearing slowly. I removed the radiator, had it repaired. Another leak was in one of the freeze plugs on the back of the block covered by the automatic transmission.

Before that it was the freeze plugs just below the intake and exhaust manifolds. :rotfl2:

[prcjeep]

I think you have a small coolant leak... mine was acting just as your describing.

I found my leak by using a loaner tool from oriellys auto for checking coolant sytem pressure. I put the deal where the radiator cap normally goes, started it up and then pumped the pressure up. With higher than normal pressure it made my leak visable that was very small and along the plastic pinch seem on the radiator and the plastics tanks. I guess it was evaporating from where it was leaking before it ever ran down very far.

[Kimber6331]

Yea this all sounds like it might be the problem. When I get some free time this weekend I'm gonna check it out. Thanks for the advice!

[Cheromaniac]

Mysterious disappearing coolant is usually a sign of a head gasket leak/cracked head. Might check your oil?

Unfortunately many '00/'01 4.0L Jeeps were afflicted with a head cracking issue and the first sign is a mystery coolant loss. The coolant slowly seeps into the crankcase through a crack in the head (almost always right in the middle between the no.3 and no.4 exhaust valve springs). Remove the oil filler cap and look in that area for the telltale chocolate milkshake-like emulsion. If left for too long, the oil will lose its lubricating properties due to coolant contamination and wipe out the bearings, resulting in low oil pressure at hot idle.

[Marco13013]

Yea this all sounds like it might be the problem. When I get some free time this weekend I'm gonna check it out. Thanks for the advice!

Did you get a chance to look at it and see where it comes from?
For info, I had the same leak sources than what Mudderoy is mentioning. Small leak from radiator fins, barely visible, small leak from a hose - easy fix, and coolant seeping from a freeze plug right below the manifold (you will see a green deposit but it will be mostly dry) - little more painful since I believe the only way to get there is to take out the intake. Oh, the last one was the shop breaking the radiator cap outlet to the expansion reservoir (had to change the radiator for this - needless to say that's when I started working myself on my jeep).

[Kimber6331]

Sorry for delay work has been picking up. I poked around today and noticed that in front of the head below the belt between the radiator and engine there were signs of a leak. Small green drip puddles settling on horizontal surfaces. I'm guessing main hose between engine/radiator?

[prcjeep]

Sorry for delay work has been picking up. I poked around today and noticed that in front of the head below the belt between the radiator and engine there were signs of a leak. Small green drip puddles settling on horizontal surfaces. I'm guessing main hose between engine/radiator?

My heater hose "weeped" out of the end of the hose, i guess just from age.The upper hose can also leak too and it runs down the front of the block.
Also i think it could be your water pump, look on the bottom side of your lower rad hose and see if you can see signs of coolant(water marks).
Another possiblity could be a pinhole radiator leak spraying onto the front of the block...

[XJ Wheeler]

Could also be the thermostat housing leaking. Just gotta get in there and track it down.

[Cheromaniac]

Sorry for delay work has been picking up. I poked around today and noticed that in front of the head below the belt between the radiator and engine there were signs of a leak. Small green drip puddles settling on horizontal surfaces. I'm guessing main hose between engine/radiator?

The three most likely sources are the water pump weep hole, lower radiator hose (where it connects to the water pump), and the thermostat housing gasket.
If it's the last one, you'll see coolant pooling on top of the water pump. If the top of the water pump looks dry and there are no stains, the leak is likely to be from one of the first two sources.
You'll need to take a look underneath to see where the coolant's coming from but your best chance of finding it is to run the engine up to normal operating temperature, shut it down, and immediately look around for the leak while the cooling system's still pressurized.

[Kimber6331]

ok so I got some free time today and Im poking around and I see water marks? on lower rad hose, and some other small areas. I filled up reservoir and going to watch it today and see where most coming from. some areas it looks like a splatter pattern, not just a simple leak/run

[Cheromaniac]

some areas it looks like a splatter pattern, not just a simple leak/run

Like I said in my last post your best chance of finding it is to run the engine up to normal operating temperature, shut it down, and immediately look around for the leak while the cooling system's still pressurized. If you wait a few minutes, it'll be too late and you might not see where the coolant's coming from.
The splatter pattern suggests that the leak is probably from the water pump weep hole, and it'll also trickle down the lower radiator hose. I had the same thing happen on my Jeep a couple of months ago and sure enough it was the water pump. At least it's very easy to replace yourself if you're a DIY mechanic.

[Kimber6331]

yea I tried that but i couldnt find anything I may not know exactly where to look but I saw nada. Though theres definitly signs of running down the lower hose. I should prob mention that the splatter pattern is towards front of the block, behind/near main wheel with timing belt. idk how to explain. its not really bad but its def a little splatter might be coming from radiator idk. maybe a pic will help since i have no idea what is wrong

[Kimber6331]

popped my head under hood today and noticed a slight significant amount of coolant already gone, and a lot more spatter pattern on front end of block. def thinking it might be radiator spatter, and then a small leak in lower hose. if the case, looking at a new radiator and replace both top and lower hose to be safe. should get another pic of it right after i park

[Kimber6331]

OK I was wrong. There is a crack in upper front of block. Coolant is slowly oozing out as I am driving. So what now?? I wish I had a picture guys but I have a flip phone with terrible lighting. Ill get around to it soon but in the mean time, this is all i got. How would I repair that? I dont think I have a cracked head because oil pressure is actually running high all day (80). I really need to get a picture.

[4.3LXJ]

If it is a cracked block, no fixing it. But there is some stuff at NAPA that is supposed to stop leaks in a cracked block. Not cheap, around $80 but people I know down there say it works. That will give you time to save and come up with another engine to swap or rebuild.

[xj4life2]

Seriuosly , get us a picture , it may not be as bad as all that. At least we can give ya a heads up.

[olliewagon]

thermostat housing

[Kimber6331]

cant get picture up until fri evening sorry. my cameras broke but girlfriend has iphone. "IF" i do have to rebuild or replace engine, what do you guys know about ATK replacement engines? I have a membership with Quadratec magazine (yes I know) and they advertise an engine ATK makes - 4.0l I-6 engine-same as mine now I'm assuming. There is no way I can rebuild my engine, I am short on time, money, tools, space, and my xj is my only vehicle. So I was looking at this. Does this seem legit? "IF" I have to?

http://www.quadratec.com/products/51107_0017.htm

[Carves]

Be careful you dont get too far ahead of yourself .. ;)

Personally ... I wouldnt be worrying about engine replacement until after making sure the leak is not the things - mostly mentioned in previous posts ...


Water pump gasket,
Water pump weephole,
T'stat Housing gasket,
T'stat housing cracked,
Heater hose extension pipe on waterpump rusted out,
A split in a rad hose,
A split in the rad plastic end caps,
A split in the rad core.

That eth-gly is slippery muck ... and compared to water alone - will find the smallest gap to seep out of.