2000 TJ Radiator Drain Valve Leak

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Dondo

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Hi All — I've been reading some on this forum, trying to figure out whats going on with my 2000 TJ Sport. The ol' gal has about 130k miles on it. I've done most maintenance on it since I've owned it (about 7 years) and overall is in pretty decent shape. I noticed last year, when it gets cold out, coolant drips from the radiator drain valve on lower corner, passenger side of the radiator. It wasn't bad enough to really worry about as it only seemed to happen when it was below freezing and the jeep hadn't been driven in awhile. A few drips is all. Well, now, the issue has grown and I'm losing about 8oz a day when it's cold out. I purchased a new petcock valve from AutoZone, unscrewed the old one and screwed the new one in and it hasn't made a difference at all. As it is now, coolant will stream out if you turn the valve a little bit, but you can halfway adjust it to get it to slow back down to a single drip every few minutes. I can get the Jeep up to temperature and it doesn't leak at all, but after I park, let it sit and it gets cold out, drip, drip, pour.....

So, I haven't delved into this too far yet...meaning, I haven't changed the radiator cap, I have refilled the overflow tank after I changed the valve. I've read some about the OEM radiator metal/plastic crimps failing, system pressurizing and not letting out though the radiator cap, stuck thermostat...etc. I don't have an issue starting to throw parts at it, but it seems strange that it only drips from the drain valve when cold. Perhaps it's time for an entire system flush, new 70/30 blend? The system was flushed probably 4 years ago, about 5k miles.

Ideas?
 
Strange indeed. Are you certain the leak is from the pet cock and not somewhere higher up the radiator, leaking down onto the pet cock making it appear as though the pet cock is leaking? (Lol, how many time can I type pet cock in one sentence?)

Old coolant won't cause a valve to begin leaking. Changing the coolant won't stop the leak.

Maybe try another pet cock valve?
 
Have you check around the valve if there is a hairline crack that when the metal contracts due to cold it opens. By the same token when it's hot the coolant circulates and the possible metal crack closes. A propane torch and some plumber lead it may be the solution but make sure is there and not from above.
 
That sentence certainly has a lot of pet cocks in it! So, I did replace the old (lets just call it the radiator drain valve) with a new one, continued to leak. Why does it only leak when cold? When the silly thing is up to temperature, no drips anywhere, temp gauge rock steady at 210. I suppose it could be leaking from somewhere else, but the coolant is literally coming out of the drain...so, yeah...I dunno.
 
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R.Flores said:
Have you check around the valve if there is a hairline crack that when the metal contracts due to cold it opens. By the same token when it's hot the coolant circulates and the possible metal crack closes. A propane torch and some plumber lead it may be the solution but make sure is there and not from above.
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Thats an idea.....not that I'm into replacing stuff just to replace stuff...but, a 21 year old factory radiator...it very well could be time for replacement. Other threads have shown replacing the radiator much sooner. I'm in KS, so 105 in the summer, 10 degrees in the winter....
 
Is this the style plug?

E04BEC63-E4D6-4FB0-B1A5-1FBDAB8165E5.png
 
Dondo said:
That sentence certainly has a lot of pet cocks in it! So, I did replace the old (lets just call it the radiator drain valve) with a new one, continued to leak. Why does it only leak when cold? When the silly thing is up to temperature, no drips anywhere, temp gauge rock steady at 210. I suppose it could be leaking from somewhere else, but the coolant is literally coming out of the drain...so, yeah...I dunno.
Click to expand...
The leak appears when it's cold because there's a crack somewhere (drain valve or radiator). As the coolant gets hot so does the crack, heat expands closing the crack, no more leak.
 
Ok so I had this same problem with this style drain plug. The plug clips in to the radiator and what I think probably happened is that the tabs that are molded in the radiator are either stripped or rounded off just enough that it’s not holding the tension needed to maintain a good seal. You said you’ve already replaced the plug, so that makes me think the problem is with the tabs in the radiator. These things are just made out of plastic so just the slightest over tightening will cause failure. Unfortunately the way I fixed this issue was I replaced my radiator and made sure I got one that has the traditional one piece screw in type plug. I hope this makes sense and I hope it helps. Good luck!

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Thor said:
This is exactly what was happening to me..
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I wonder if it is possible to get the tabbed piece pulled out of the radiator? It looks like you might be able too, but it also looks like one of those things that should be so simple, but after trying to do it for 45 minutes, cursing, standing up, stomping around, that you say to heck with it, and buy a whole new radiator.....
 
That style plug is a 2-piece construction. If you only have the wing nut section out, than you should be able to get the piece that has the tabs out for sure. But I still think your problem is going to be the tabs that are molded into the radiator itself being rounded off and not holding enough tension to seal the plug.
 
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