Tracing coolant leak

So the other morning it was about 9 degrees, so I let my 91 warm up in the driveway for about 15-20 minutes. I come out to leave and there are two sizeable puddles of coolant underneath, one under the passenger and one under the driver side, with steady drips still coming down. I shut it down and let it cool off and sit for a couple days until I could take a closer look.

I cannot for the life of me find a glaring leak now. It looked like it was near the radiator, and that was where it was wet. Dried it off and cleaned it up, and now I can’t get it to leak again. I let it sit in the driveway idling for a good half hour, confirmed the thermostat opened up and it wasn’t overheating, and no leak, at least to the ground. The radiator is also topped off. Cap is ~6 months old.

The only thing I can find that I’m not even sure is an issue, were these wet spots on both radiator tanks, near the inner seams. They will pop up while its idling, then sort of dry themselves up. This is what I’m talking about:



There were a handful that would show up and disappear, on both tanks. Could the tanks both be cracked at this seam from the cold? I’m not a fan of just replacing things arbitrarily hoping they fix the issue without understanding it.

tl;dr: XJ dumped coolant when super cold out, now it’s not. Does my photo look like a cracked radiator tank?

Thanks.


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If your tires were old, and did not hold air, wouldn't you replace them ? Aftermarket radiators do not last anywhere near the lifespan of genuine Jeep radiators. If you plan to keep your Cherokee a little preventative maintenance of the cooling system seems like a good idea.

The plastic tanked radiators have a rubber seal that gets compressed under the crimped seam. It's a common failure point. It's possible it got cold enough for the metal shrinkage to cause a leak, although rubber actually swells when it gets cold.

^ lawsoncl hit the nail on the head . It was a bit colder than you mentioned here last week we had 7 plastic radiator vehicles with sudden leaks where the plastic tanks crimp onto the radiator ends that were only present in the extreme cold .

I agree also. Case of the "Winter Leaks". I don't get them in my '00 but used to get them in my '96. Primarily from the heater control valve. Which in hindsight I probably should have just gotten rid of. But also just around all the hoses at where ever they clamp to. If this is the problem they make this stuff called Indian Head.

https://www.amazon.com/Permatex-205...ocphy=9003405&hvtargid=pla-571549195137&psc=1

It was suggested to me that I try this. Never did though. I hear it works well but if you ever plan on taking off a hose where you applied this I hear it is going to be fun. And not in the good way. Apparently this stuff is pretty much glue. So use it at your own risk. LOL.

I'm guessing your tanks are cracked. You can rent pressure testers,but it us possible to make them worse.

New radiator up friend!

I appreciate everyone’s input, I’m guessing it was an example of a “winter leak,” because it hasn’t happened since. I will probably end up replacing the radiator soon anyway, since I planned on doing a cooling system overhaul before spring.


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throw some of those fiber stop leak pellets in it.
They actuall put a couple of those in new rads at the factory

actually i retract that last post ...you can try those fiber discs but if you have a cracked tank it prob wont do anything.

Is it not possible to edit/delete posts anymore?
I was gonna ad that you can get uv die and add it to your coolant and use the special light and glasses to see where the coolant is glowing

outlander said:

Is it not possible to edit/delete posts anymore?

Click to expand...

It could be a Red vs Black thing, paid members should have more privileges.

I've been Red since 2004 and the information found here has been worth it, many times over.
Support !

how much are dues now anyway,since we veered off original topic...

**EDIT**
I found the info.....sorry for the thread hijack.