I recently found a puddle of coolant under my TJ. I traced the leak to one of the transmission cooler line fittings. But looking at it, the coolant seems to be coming from between the plastic housing and the flange part of the metal fitting, not the actual thread of the hose barb. I’ve been trying to think of a way to fix this, but I’m at a loss. Anyone have any suggestions? Or am I going to be replacing the whole radiator?
Leaking radiator
- Thread starter DanOinAkron
- Start date
I have a manual transmission so I don’t know a lot. But doesn’t the metal flange part you are referring to screw into the radiator? If so might be able to remove it and clean it up use some thread tape and reassemble. Or maybe it just needs to be tightened some?
JKP
TJ Addict
It would be leaking ATF from the hose barb threads.
You might be able to remove the fitting from the radiator tank and reseal it, but I'm not sure as mine are MT. I'm sure somebody knows if that's threaded into the tank, or glued in or..
You might be able to remove the fitting from the radiator tank and reseal it, but I'm not sure as mine are MT. I'm sure somebody knows if that's threaded into the tank, or glued in or..
Take a look at the fitting in this thread. The factory fitting appears to have an o-ring behind the thin washer. I realize that your fitting isn’t a quick coupler, but your fitting may have an o-ring in the same location that could be replaced.
https://wranglertjforum.com/threads/transmission-cooler-quick-connector-leaking.72506/post-1378211
https://wranglertjforum.com/threads/transmission-cooler-quick-connector-leaking.72506/post-1378211
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Clean the surrounding area thoroughly and then do an inspection of the area with a bright light to see if there is possibly a hairline crack starting at the top of the threaded area due to the insertion of the threaded adapter.
LONGJP2
TJ Expert
The fitting for the hose barb is what holds and seals the trans cooler to the inside of the radiator.
You might be able to tighten the fitting nut (not the barb) to stop the leak.
You might be able to tighten the fitting nut (not the barb) to stop the leak.
Thanks for the good ideas. From looking at new radiators on line, I’m thinking the silver part and large bronze colored nut part are molded into the body. And the hose barbs thread into that. But maybe I’m wrong and the bronze part threads into the silver part. But regardless, I guess I’ve got nothing to lose by removing the lines and the hose barbs and seeing how it all goes together. Maybe there is an o-ring in there or something I can tighten.
This is very similar to my situation. But it seems hard to believe just screwing that in would give enough of a press fit to seal it permanently. But maybe with some RTV on it, that might work. I’ll have to disassemble Mine to see what my options are.
So I finally got around to trying to fix this leak. I removed the transmission line and unscrewed the nut. It appears the large jam nut just tightens up and pushes the washer tight against the housing To seal it off. Great I thought, I just have to tighten it up a bit. Well I’ve been tightening it little by little, but it’s still dripping. Then I tightened some more and it started leaking more. So I backed it off slightly and it’s better but still drip drip drip. From what I can see, it looks like the coolant is coming through between the nut and the washer. Should I try some Teflon tape on the threads to possibly seal it up? Any other ideas? This seemed like an easy fix (for a change), but I guess not.
So when I tried to remove the larger jam nut, the entire threaded fitting unscrewed from the transmission cooler. Does anyone know if there is suppose to be an o-ring inside there? (on the inner thread to seal the transmission fluid, not my other coolant leak).
note, the weird blue color is a reflection or something, it doesn’t really look that color.
note, the weird blue color is a reflection or something, it doesn’t really look that color.
Don’t know, but would try it. I’d also try some Teflon tape / paste if they make a high temp one.
ChasUGC
TJ Enthusiast
I would definitely clean the threads on both side with a plastic tooth brush until they are free of gunk and particles. A squirt bottle with water and the plastic tooth brush should do it. If it isn't seating right, because of all the gunk, that may cause leaks. All that pink stuff around the hole, looks like something may have broken up, like an O-ring. Can you contact the manufacturer of the radiator and ask them if there is supposed to be an O-ring in there, or if they recommend Teflon pipe tape on the threads to seal it, because it was leaking there? Ask them if they have email so that you can send them pictures.
The manual transmission Mopar radiator and the automatic one are the same radiator. When the radiators are made, the lower plastic tank is drilled to fit the automatic transmission cooler into it. I don't know much about how the cooler is installed but it must have something to keep the coolant from leaking out. Most probable is an oring. In the pic where you are holding the fitting and can see the part that threads into the radiator, there is a round area of clean metal that looks like it might be where an oring is supposed to go. I think I'd try an oring. Get one of the right size in both diameter and thickness. I'd put a little dielectric grease on it before installing it.
Personally, I suspect you are going to be replacing your radiator sooner rather than later because if it's leaking here, it's likely the radiator tanks will crack as these shitty Mopar radiators are known to do. Just the way it is. I put a Denso in my Jeep not because I think it's for sure better quality but because I believe it's similar quality to the Mopar but at a lot lower price.
Personally, I suspect you are going to be replacing your radiator sooner rather than later because if it's leaking here, it's likely the radiator tanks will crack as these shitty Mopar radiators are known to do. Just the way it is. I put a Denso in my Jeep not because I think it's for sure better quality but because I believe it's similar quality to the Mopar but at a lot lower price.
It's tough to tell in the pictures, but that looks like a soft metal crush washer. If it is, it may be deformed. Sometimes turning them around, or some gentle flattening with a hammer on a flat surface can bring them back, but I would take it into your FLAPS and get a new one. I would also clean both the radiator side and the plug side so there's no debris.
If that doesn't work, like others have said you could wrap the threads with teflon tape.
If that doesn't work, like others have said you could wrap the threads with teflon tape.
I haven't had a cracked Mopar radiator on my TJ since 1999. The OEM Mopar radiator used in TJs is not "known" for cracking, it's only that some crack... even the highest quality parts can and do fail. My current '04 TJ is still on its original Mopar radiator. My previous '97 TJ bought new had a couple cracked radiators within a year or two of buying it new but that was caused by an early design flaw fixed in mid-99. I have had no more radiator issues since then.
LONGJP2
TJ Expert
I don't think the fitting is supposed to seal against the outside of the radiator.
Screwing it in pulls the trans cooler against the inside of the radiator.
If there's a leaking seal, it would be between the two parts in this picture.
You might try thread sealer on the fitting and some RTV everywhere else.
YRMV
KennethS
TJ Enthusiast
I was thinking the same thing. But if there's supposed to be an o-ring there, where did it go? Not installed during manufacturing?
My 2005 cracked. Lots of people have posted their plastic radiator tank cracked. So, the plastic tanks do indeed crack. How often? No idea but it's often enough that lots of people have had it happen to them. Either way....Mopar isn't known for quality. Sucks but that's just how it is. We all know these radiators like to fail as they age. That's why people who want to buy Mopar radiators are always trying to find one to keep on hand because everyone who knows much about these vehicles know the radiator is a weak point.
I've had other non Jeep vehicles with plastic tank radiators crack as well so it's definitely a thing.
I suspect the OP won't be able to fix his radiator but hope he can. Either way, once it starts leaking in one spot, I doubt the rest of it has much life left. I'd be replacing it if I was the OP but he might not have the money to replace it now so if not, it's worth trying a couple things to repair it.