Losing Coolant!

[BooDa]

Hey there, first time poster, long time reader! 

So I have a Jeep 2001 TJ 4L.
A couple weeks ago while I was driving I noticed that I was starting to overheat, my knee jerk reaction was thermostat.
Luckily I was a block from home, so I let the thing cool down and opened the hood. No coolant in the reserve, open the rad, no coolant on the top of the rad.
So I fill it up with 2 of those 1.89L jugs you get from a gas station (high performance) 50/50 mix. Now I know that I should be using Zerex G-05, (can get at walmart I believe?) Anyways, after I fill it, it runs fine as far as temp, so its not the thermostat. Good news I guess?

Now here is where the problem is, I checked the reserve and top of the rad again a week later, the reserve is empty and the top of the rad has no coolant again. So I check for leaks on the rad anywhere, on the hoses, nothing on the rad, top hose, bottom hose look in great shape with no visible leaks.
Check the send and return for the heater core, looks fine. Run the Jeep till the thermo kicks in and crank the cabin heat with the fan on full, no coolant smell and it gets hot.
So I start to panic and think that I might have coolant leaking into the engine. So I take the oil filter off to see if the oil has a milky look to it. The oil looks fine, might need a change in 1000K or so but looks good. I'm not getting a exhaust that has a white look to it. So that might be good news too.

So my only other theory is.........wait for it........Is I haven't flushed my cooling in a long time......
Is it possible for coolant to break down in the quantities I have added to the reserve and rad already,  and what is missing from there again and turn to sludge and collect at the bottom of the rad? Actually as I'm typing this......I'm wondering if there is a bleeder valve for the rad I can check.
Oh one last thing, I am a bit of a maintenance noob and I'm trying to learn as much as I can with a Haynes manual (which I find about as vague and a politician in the middle of a sex scandal).
Any ideas?
Cheers!!!
   

[hps4evr]

well if you're 100% certain there are no outside engine leaks then your only other option is inside. it could be burning it slowly. that year of 4.0L had the odd tendency to crack cylinder heads and leak coolant. the other thought is that when it over heated it pushed a lot of coolant out of the system and when you topped it up you didnt clear the air out of the system. which may sucked the overflow/reserve dry and now the system is low.
now, ive seen cracked rads that only leak at certain times, water pumps that only leak when hot or cold. even the wrong rad cap can cause some funny cooling system issues. so to save yourself some money in the long run you may want to bring it to a shop and have a pro test the system for leaks. once it starts getting cold out your problems will only get worse.

[BooDa]

100% certain? well as good as I can tell there are no leaks.....
This odd tendency that you speak of for 2001 TJs to crack cylinder heads is gonna make me look again at the hoses for leaks lol
Well I'm gonna top it up again in hope that maybe it just burnt it off like you said, and possibly do a coolant flush in the very near future.
Now that I think of it, could a coolant leak could cause rough running on cold starts and poor fuel consumption.....Im mean above and beyond what is considered "poor" for a TJ of that year?

Well, I'm off to top it the rad and reserve off again and look for a good place to test the cooling system, any recommendations?
Let ya know how it turns out.

 

[AV.NINE]

100% certain? well as good as I can tell there are no leaks.....
This odd tendency that you speak of for 2001 TJs to crack cylinder heads is gonna make me look again at the hoses for leaks lol
Well I'm gonna top it up again in hope that maybe it just burnt it off like you said, and possibly do a coolant flush in the very near future.
Now that I think of it, could a coolant leak could cause rough running on cold starts and poor fuel consumption.....Im mean above and beyond what is considered "poor" for a TJ of that year?

Well, I'm off to top it the rad and reserve off again and look for a good place to test the cooling system, any recommendations?
Let ya know how it turns out.

 

Theres a good chance that it is leaking somewhere but evaporating (due to heat) before it puddles. That would be a leak from rad hoses to block type thing.

Go pull out your dip stick (engine oil) and take a picture of it. If its black your good if its milkey I got bad news for ya.

Throw up the pic so we can see it.

Hell come over if you want and Ill run through it for ya too. Im in the NW 403-991-5950

[morerpmfred]

The rad on my jeep leaks at the crimp of the plastic tank and it hard to see where it leaks. It does not leak all the time just whenever it is in the mood. lol. It will use no antifreeze for a year then in a day a couple of cups gone.

[tubby]

The rad on my jeep leaks at the crimp of the plastic tank and it hard to see where it leaks. It does not leak all the time just whenever it is in the mood. lol. It will use no antifreeze for a year then in a day a couple of cups gone.

That is an XJ trait Andy.

They leave a puddle of antifreeze once a year. I got used to it. It's kinda like a dog marking it's territory .

[BUKI]

Have you done a pressure test?  That will tell you if you have a leak. Also check for coolant on the seep hole on your water pump.  Is your rad cap good. Should change soon as it probably has never been changed.  I think you need 16 pounds of pressure to keep bp where it should be.

[BooDa]

Hey all, in the spirit of Halloween I am brining this one back from the dead!
Thanks for all the suggestions so far, they have been a big help.
So a lot has happened since I last posted on this forum.
Firstly I moved to Squamish BC. Love it here, the wheeling is insane, like McLean Creek on steroids.
So when I first got out here, I had to fix a cam shaft and lifter issue. So when that happened, the water pump and timing chain was replaced too. I asked him to take a look at the water pump to see if there was any indication of leaks from there. That way I could say that this was a water pump issue and move on.
No such luck, he said it looked fine and replaced it anyways. After the new system was in place, I got him to do a pressure test on the system (not sure of the pressure he used but if 16lbs is standard I would assume he would use that).
The system came back fine. So, when I first moved out here, I was living in the burbs, the commute of one and half hours to two hours commute one way. It was very stop and go traffic and very little highway traffic, if any. That was for about 7 months, and during that time, I topped up the rad once. Now that I live in Squamish, it's all highway driving and very little stop and go if I encounter any at all. During the 6 months that I have been commuting from Squamish, I have topped up the rad 3 times.
So what would cause coolant loss at high speeds? Checking the Almighty Google, a lot of Americans are saying heater core or hoses to the heater core. Again, no smells when I turn on the heat in the cabin.
I was thinking of just replacing the upper and lower rad hoses and flush the system and start there now that water pump is ruled out.
And thanks for the offer AV.NINE, very much appreciated.

They leave a puddle of antifreeze once a year. I got used to it. It's kinda like a dog marking it's territory .

LMAO!! That is nice one!