Radiator won't play well.....

So, what do you do when you know your radiator leaks, but it only does so when it wants to ?

I even took it to have it pressure tested today, and it showed no signs of leakage, and they even left it pressurized in the tank for over 30 minutes.

It seems to only leak when it is below 35 deg out, and aside from the first time, it never leaks more than a 3" diameter wet spot on the driveway maybe one time every week.

TRCM said:

So, what do you do when you know your radiator leaks...

Click to expand...

Have you actually seen it leaking from the radiator...or just the wet spot? Does it leak when running or when off. Hot or cold? What are you driving??
:anon:

There are several places from which leaks can "migrate" to the front end and appear under the radiator. More info needed.

Namely, pretty much everything else but the heater core can mock a radiator leak by the time it hits the ground. Water pump, thermostat housing, and all your heater hoses are all in the same area as the radiator.

OK, 3 weeks ago, when I came out of the bank, there was a puddle of antifreeze under the pass front corner of the jeep (96 cherokee sport). I could see it dripping from the underside of the radiator.

Got it home, and tried to find the leak by removing the grill and headlight bucket, but couldn't find any obvious leak.

Let it set for a few days, then I started it up and let it get up to temp then shut it off. Did this several times over 2-3 days....no leak showing, but there was always a very small amount of moisture at the bottom pass side at the fin-tank area in front.

Ok, start driving it again... no leak. Then 1 day when it was low 30's out, I could smell the antifreeze and could see the leakage where it had blow out onto the front bumper, and there was a little bit more moisture at the same location (bottom pass side front ), but not even enough to make a spot on the driveway. It did this several times over a week, but no real water loss, less than 3/4" drop in the reservoir. When ever it is 35 or less out, it seems to leak just a tiny bit.

Well, like I said in the 1st post, it passed the pressure test...so now I am wondering what's going on. The leakage is not coming from the water pump of hoses or anything else. And there is no staining in the area of the moisture, but there are rust stains in the middle of the core area, but again, no leaks when under pressure (and he used machanical agitation to try and find it - ie leather hammer).

No, I haven't actually seen a leak, just moisture in an area it shouldn't be (and a minor coolant drop in the reservoir), especially after a 20 mile drive @ highway speeds.

I'm almost ready to just put a new gasket on the petcock and put it back in, and send this $200 radiator that don't fit 100% like it should back to CA. Reason being, I am almost starting to think it was a shrunk gasket on the petcock that was leaking, since they couldn't find a normal leak.

I had something similar on a '92 Sport and the mechanic explained that the factory rad connected the fins to the side tanks through rubber fittings. When the rad is at operating temperature everything expands and you won't see any leaks. When the rad gets old and it is cool outside the sucker cools down, the fins compress and leaks start.

Probably not what you want to hear but a rad replacement was the answer.

HTH
Todd

Understand, but this is an all metal radiator, you can actually see where the fins are soldered to the tanks.

Could it be condensation? Most radiator leaks get worse.... Not hide. This sound like a type of pinhole leak that a 5 dollar autozone stopleak treatment will fix.

Pressure test it filled with water heated 200+ degrees. That should cause any cracks to open up.

Personally, I would leave it until it show it self (get worse).

I'd agree on the petcock...whether it's a gasket (?) or just not secure, or broken etc.

Reason #2043 to never actually USE the petcock.

It could also be a leak at the top hose dripping down to "the puddle"

I vote for the upper hose. About a month or so ago, the original upper hose in mine decided to go the way of the Dodo... Fortunately, I was within striking range of a parts hose and did not loose all that much coolant.

Rubber hoses... Bane of the system.

NO, there was no leakage anywhwere else but the bottom pass corner.....no uppper hose, no water pump, no lower hose........

I had to cut the hoses off they were sealed so well........