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Discussion Starter · #1 ·
The last month or so I have not been able to consistantly get heat coming out of any vents in my 04. I noticed probably 2 months ago that I was low on coolant(at that time I believe I got heat with no issues) so I topped it off. Now I am low again and on top of that dont get heat half the time. It will warm up for awhile then go cold. Figured a leak somewhere could be the cause of this. Haven't noticed any puddles of coolant and cannot see upon inspection where itd be leaking from. anyone know of any common leaks that TJs have that maybe arent that noticeable and are rather slow leaks?
 

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How does your oil look? Does it look like coffee with a lot of cream in it? Check.
 

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Nice 1999-era attempt at humor. What a DB...
 

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Discussion Starter · #4 ·
Ill check the oil tomorrow i didnt know it could leak into the oil.

And like I havent tried googling it??? Do you think if I found the answer on google I would post on here??
 

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Discussion Starter · #6 ·
Have you tried a pressure test? that should help you find the leak. I would also check your thermostat it may have failed and locked open that could be the reason for no heat.
pressure test is next on the list. Going to rent one from Oreilly tomorrow. Could the thermostat still be the problem I do get heat sometimes.
 

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Sounds like to me that you are getting the no heat problem when your coolant is low. Is that correct? If so then that is why you are getting little to no heat, and it is common with low coolant levels. I would not replace parts like tstat just because you have no heat and low coolant.

Mine was leaking as well and I couldn't see any leaks. Ended up being the 4 small (7/8") freeze plugs in the head. The coolant would leak from them and pretty much immediately be burnt off by the exhaust manifold. So I never saw leaks or puddles either.
 

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A hairline crack in the head can leak coolant into oil gallery which makes coolant level slowly go down and oil level slowly go up and turns oil into a contaminated non lubricating milkshake looking mixture leading to engine failure over time

Most common in poor head design of 2000 and 2001 4.0 engine
 

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Discussion Starter · #10 ·
Sounds like to me that you are getting the no heat problem when your coolant is low. Is that correct? If so then that is why you are getting little to no heat, and it is common with low coolant levels. I would not replace parts like tstat just because you have no heat and low coolant.

Mine was leaking as well and I couldn't see any leaks. Ended up being the 4 small (7/8") freeze plugs in the head. The coolant would leak from them and pretty much immediately be burnt off by the exhaust manifold. So I never saw leaks or puddles either.
Yes. topped off the coolant again today and my heat worked for 15 minutes driving and also another 10 in idle. was looking while the jeep was idling at home under the hood and below the jeep. could not find any leaks. this may be my problem because the coolant is obviously going somewhere, but I could never see a leak.
 

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Yes. topped off the coolant again today and my heat worked for 15 minutes driving and also another 10 in idle. was looking while the jeep was idling at home under the hood and below the jeep. could not find any leaks. this may be my problem because the coolant is obviously going somewhere, but I could never see a leak.
look at the exhaust/intake manifolds, right at the top side where they mount to the head are where the freeze plugs are. You will likely see what looks like corrosion in a few areas and if so that is where the leak it. All 4 of mine had holes rusted through them. I'm surprised I didn't have a worse leak considering the size of the holes but I guess the manifold gasket kept them somewhat sealed.
 

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Discussion Starter · #12 ·
look at the exhaust/intake manifolds, right at the top side where they mount to the head are where the freeze plugs are. You will likely see what looks like corrosion in a few areas and if so that is where the leak it. All 4 of mine had holes rusted through them. I'm surprised I didn't have a worse leak considering the size of the holes but I guess the manifold gasket kept them somewhat sealed.
Is your motor a 2.4/5? I watched a video of a 4.0 and it had 5 on the side down where you're talking about. Do you have to take the manifold and everything else on that side of the engine out to get to the plugs?
 

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Mine is the 2.5 but the 4.0 has them as well. Now I'm not talking about the big block freeze plugs, there are small ones in the head that I'm talking about. The ones in the block will generally create a puddle or at least visible signs on the ground because they are below the exhaust. I will try to find the pic I have and yes the exhaust and intake manifold have to come off to get them.
 

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Here is the pic of the side of the 2.5 engine. The 4 little brass plugs I. The head is what I am referring to. I did also change the ones in the block and even seized to opportunity and put in a block heater in place of one of them.
 

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Discussion Starter · #15 ·
Here is the pic of the side of the 2.5 engine. The 4 little brass plugs I. The head is what I am referring to. I did also change the ones in the block and even seized to opportunity and put in a block heater in place of one of them.
So the four on top would cause antifreeze to leak off and essentially just evaporate so you would not see obvious signs of leakage? That would make sense. I do not have a chance to look under the hood but will later. Can you see the corrosion you mentioned earlier without taking off the exhaust/intake manifolds?
 

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So the four on top would cause antifreeze to leak off and essentially just evaporate so you would not see obvious signs of leakage? That would make sense. I do not have a chance to look under the hood but will later. Can you see the corrosion you mentioned earlier without taking off the exhaust/intake manifolds?
yeah I could see it and yeah I never ever saw a leak but was losing about a gallon a month. After pulling everything apart even noticed that some of the antifreeze was being sucked into the intake. The gasket was saturated and the intake port was nasty and slimy!! Got it all cleaned up though and no issues since.
 

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Discussion Starter · #17 ·
So how hard of a repair was it? The plugs themselves don't sound hard but taking the manifold apart is what concerns me. I can turn a wrench and do the basic repairs.
 

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Not too long ago I had a similar issue with missing coolant.. My radiator had cracked near the filler neck which caused low pressure. The coolant wouldn't leak out since it was up high, but would evaporate out from the heat and low pressure.
 

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Discussion Starter · #19 ·
Not too long ago I had a similar issue with missing coolant.. My radiator had cracked near the filler neck which caused low pressure. The coolant wouldn't leak out since it was up high, but would evaporate out from the heat and low pressure.
So new radiator I take it. Was the low pressure obvious?
 
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