Leaking automatic transmission oil from lower radiator

[SeanMc5]

Hello all,

That title wasn't phrased very well, but in essence I'm trying to figure out what part(s) I need to replace for my leaking transmission oil system. The leak is happening right at the side of the oil tank below the radiator. This is the only picture I have on hand right now:


It's the passenger side tube on the tank directly underneath the radiator. The leak is happening right at the silver washer looking part.

I should note that I'm mostly sure that it's transmission oil, but it very well could be the antifreeze/engine coolant. But from all the diagrams I've seen this tube is the transmission oil line though.

I'm wondering if this is something I can replace easily or if there it's going to be a bigger job (like replacing he radiator itself) I'd be happy to answer any questions you might have. Any help would be much appreciated!

 

[Chris]

That's hard to tell. You could have one of two things going on... it could be a crack in the lower portion of the radiator, or it could be that that brass fitting needs some teflon tape wrapped around it to seal it better. I'd try the latter, then see if the leak continues. Don't wait too long, you don't want your transmission spewing fluid, that wouldn't be good!

 

[SeanMc5]

That's hard to tell. You could have one of two things going on... it could be a crack in the lower portion of the radiator, or it could be that that brass fitting needs some teflon tape wrapped around it to seal it better. I'd try the latter, then see if the leak continues. Don't wait too long, you don't want your transmission spewing fluid, that wouldn't be good!

I see. Is the fitting something that can just be unscrewed? It looks like something I could take a crescent wrench too and get it out, but I'd like to make sure.

 

[SeanMc5]

I would use a crescent wrench to see if the larger brass nut could be tightened a bit.

I would also use the crescent to hold the larger brass nut while you snug up the smaller nut with a box end wrench.
If that doesn't work, i would try @Chris' idea using teflon tape to seal the threads

Alright, that answers my followup question of how that nut is attached. I'll try tightening it first then. I won't be able to get to it until tomorrow but I'll report back what happens!

 

[KCsTJ]

I would use a crescent wrench to see if the larger brass nut could be tightened a bit.

I would also use the crescent to hold the larger brass nut while you snug up the smaller nut with a box end wrench.
If that doesnt work, i would try @Chris' idea using teflon tape to seal the threads

 

[Flivver250]

I would remove it, clean the mating surfaces and use the teflon tape as suggested.

 

[KCsTJ]

I would remove it, clean the mating surfaces and use the teflon tape as suggested.

Thats probably the best way to resolve your leak problem.
However doing this may take a few minutes and in the meantime fluid will want to drain out of the line and radiator so make sure you have something to plug up the line and the radiator.

 

[SeanMc5]

Okay update:

It's most definitely leaking radiator coolant

I tried tightening the larger brass nut, did not help. I then tried taking it off to put the teflon tape around it as suggested. However, the entire fixture does not seem to come out of the radiator. I'm imagining that there is a seal on the inside that the nut pulls toward itself to seal from the inside. I did put tape around the threads I could see but that did not help and now my leak is slightly worse than before . . .

Here's a picture of the overall area I'm working on and then a close up of what it looks like with the nut off.

 

[Chris]

That thing should come out of the radiator, it may be in there with some sort of Loctite, but I'm not sure why it would be.

Sounds like you're going to need a new radiator anyways at this point.

 

[SeanMc5]

That thing should come out of the radiator, it may be in there with some sort of Loctite, but I'm not sure why it would be.

Sounds like you're going to need a new radiator anyways at this point.

Unless they put Loctite in the stock radiator then I don't think that's the case. I thought it odd too. It would go in a little bit, maybe an 1/8th of an inch of play but wouldn't come out any further, and I was giving it a good tug.

That's that I was afraid of. Is putting a new one in all that difficult? I was doing some reading on it and didn't seem terrible. I was also reading that it's good to redo the whole coolant system at the same time, is that true as well?

 

[Chris]

Unless they put Loctite in the stock radiator then I don't think that's the case. I thought it odd too. It would go in a little bit, maybe an 1/8th of an inch of play but wouldn't come out any further, and I was giving it a good tug.

That's that I was afraid of. Is putting a new one in all that difficult? I was doing some reading on it and didn't seem terrible. I was also reading that it's good to redo the whole coolant system at the same time, is that true as well?

Putting a new one in isn't all that difficult, just make sure to use an OE Mopar radiator.

You'll want to check out this thread: Jeep Wrangler TJ Cooling System Overhaul FAQ

If you're already doing the radiator, you'd be dumb not to replace the water pump and thermostat at the same time, that way at least your cooling system is all brand new.

I haven't messed with those brass fittings on my radiator, but someone on here (can't remember who) was talking about it a few weeks ago and mentioning they had to get different brass fittings to put in since the ones that came with their new radiator had the wrong size nipples on them. Apparently they were able to get the fittings out without any issue.

 

[SeanMc5]

Putting a new one in isn't all that difficult, just make sure to use an OE Mopar radiator.

You'll want to check out this thread: Jeep Wrangler TJ Cooling System Overhaul FAQ

If you're already doing the radiator, you'd be dumb not to replace the water pump and thermostat at the same time, that way at least your cooling system is all brand new.

I haven't messed with those brass fittings on my radiator, but someone on here (can't remember who) was talking about it a few weeks ago and mentioning they had to get different brass fittings to put in since the ones that came with their new radiator had the wrong size nipples on them. Apparently they were able to get the fittings out without any issue.

Alright good to know. Hoped I could fix it easily but alas. It's the end of that radiators life span anyway so expected something to happen soon.

 

[Chris]

Alright good to know. Hoped I could fix it easily but alas. It's the end of that radiators life span anyway so expected something to happen soon.

The general rule of thumb is you can expect to overhaul the cooling system (including the radiator) around 100k miles. However, if you have a vehicle as old as the TJ and it's using the original cooling system, it's overdue for it anyways.

 

[SeanMc5]

The general rule of thumb is you can expect to overhaul the cooling system (including the radiator) around 100k miles. However, if you have a vehicle as old as the TJ and it's using the original cooling system, it's overdue for it anyways.

Yeah, I just hit about 117 I believe or right around there. My time has come.

Thanks for all the help though!

 

[Chris]

Yeah, I just hit about 117 I believe or right around there. My time has come.

Thanks for all the help though!

No problem at all! At 117k miles and well over 10 years of age, it's overdue for it anyways! That's not bad though. That means your factory radiator lasted quite a long time! Way more than those cheap aftermarket brand radiators do.