'02 Impala 140.2k, Coolant Drip

[Colt Hero]

'02 Impala 140.2k, Coolant Drip

Looking from underneath, the drip is coming out of the center of the cicular black (mounting bumper??) where the driver-side lower corner of the radiator sits. On this car, this is also where the drain cock is, but it's not loose. Can't see anything above or around the area leaking anywhere. Radiator front face has slightly-darker regions on the fins, but there is no liquid anywhere and does not appear to be leaking. Can't see the very bottom corner of the radiator on the engine-side (where the leak appears to orginate) because it sits inside a body-integral sheet-metal pocket that blocks sight of the bottom two inches. Can barely see the plastic drain cock.

Is there any way to prove the radiator has a leak without removing it? Can it be pressure-tested in place? I probably should've pulled the drain cock to check its gasket, but I doubt that's the problem.

[maxwedge]

Get a pressure tester on it, get underneath and see what's what.

[Colt Hero]

Reflecting on my original post, is a pressure test really going to reveal anything I don't already know? It's just going to leak more, right? And I still won't be able to tell from where.

I'm going to check the O-Ring on the drain cock and if that's not it then I think the radiator has to come out, no?

[maxwedge]

Still kinda guess work, I'd march on and try to pinpoint the issue.

[Colt Hero]

Looks like it was the O-Ring on the drain petcock. Tried to get the exact O-Ring from the dealer this morning but they were closed, so I ended up buying a blister pack from Advance Auto. There was one in there that looked pretty darn close to exact. Seems to have stopped the leak.

Had to laugh, though ... for about an hour off and on I was trying to get the plastic petcock out by pushing the two tabs with my thumbs - to no avail. Finally felt around the edge and realized a socket could be sleeved over. 19mm did the trick!

Then, of course, the temp gauge spiked to about 3 lines past mid-scale due to all the air locked inside, but I managed to burp that out and all appears to be fine now...

[Colt Hero]

Darn! Spoke too soon! After installing the new O-Ring and driving the car for a day without any sign of leakage, the wife takes the car for a VERY SHORT trip early Sunday morning (5 mi each way) and a 10" x 16" damp spot appears on the driveway afterwards. It's leaking again. Guess the radiator will have to come out...

Anybody recommend a particular replacement brand? Can I pay as little as $125 at Advance (Ready Rad), or do I have to pay $250 for AC Delco?

[Colt Hero]

Couldn't do much today with the Holiday and football, but I DID see where the leak is. After the upper radiator hose gets really hot, the coolant comes streaming out in an arc through what looks like a pinhole leak in the plastic side tank near where the inlet hose connects. It's definitely not the hose. Looks like the tank has some molded seams to it and the coolant just starts to magically bubble then stream right out of the face of the plastic on the engine side.

I'm going to pull it out tomorrow, but if it's a crack in the side tank, is this in any way salvageable? Seems like a waste to ditch a radiator due to a pinhole crack in a plastic side tank...

[maxwedge]

That really cannot be repaired on a long term basis, 2 stage epoxy maybe but it won't last.