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'02 Impala 140.2k, Coolant Drip

'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.

Just check out the yellow pages and ask around - there are likely shops in your area that specialize in heating & A/C for the car.

They can pressure test your system and identify the leak point.

Reflecting on my original post, I’m starting to wonder if a pressure test will tell me anything. Won’t it just leak more … and I STILL won’t be able to see from where.

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

The point of the pressure test is to make it leak - if there is a place for it to leak. The point about going to a shop is that what’s these people do all day every day for a living. But, if a) you’re certain that it is antifreeze/coolant leaking, and b) it isn’t coming from the drain or from the upper radiator hose (the lower hose is probably on the other side), then a leaky radiator is basically all that’s left.

It’s definitely antifreeze that’s leaking. Many years ago, I pressure tested a radiator that I had pulled out of a wreck in the junkyard. Looked to be pristine, but I didn’t know and didn’t want to install before knowing. Turned out it was good.

In this case, I know there is a leak - just can’t see exactly where it’s coming from. If it’s not the drain cock O-Ring, I think the radiator will have to come out. Then I can do the pressure test and see exactly where the leak is.

But I don’t think the pressure test is going to help me while the radiator is still in the car because I can’t see every inch of the radiator. It’ll probably just leak harder from the same general area (unless it leaks higher up somewhere and doesn’t vaporize, allowing me to see the liquid leaking). But I don’t smell coolant vaporizing, either, so I don’t think that will happen…

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…

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…

It could well be worth a proper diagnosis before throwing parts at it. I imagine a radiator is at least $200, and if it turns out to be a bad $15 cap the analysis would be money well spent.

I don’t think it’s the cap in this case. It’s leaking from the other end of the radiator. And since I cannot see exactly WHERE it is leaking FROM, I think it has to come out, be tested, etc. Or maybe the leak will be obvious at that point and the testing won’t be necessary.

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? Not sure what to look for in a radiator other than to match up the exterior dimensions…

I am guessing the plastic end tanks on the radiator is starting to leak. It maybe time for a new one.

a new one won’t set you back to much,carcode,1380079,parttype,2172 And this project is probably a breeze compared to the intake manifold gasket.

Your car is old enough to need a radiator. This should be very easy to diagnose. Just top off the coolant, throw a pressure tester on it, and look for the trickle of coolant. These cars do have a plastic tanked radiator, so it probably developed a crack or started leaking around the crimp on that side. Also, the drain cock seal is not likely to start leaking unless it has been disturbed recently, and that is still a rarity. Had you recently opened the drain cock to service the system and that prompted you to suspect it was damaged somehow? If not, you can, with great certainty, rule out that as a potential problem. I suspect you will be replacing the radiator in this car. It is a nearly nine year old plastic tanked radiator with over 140k miles on it, so it has served its purpose.

Yeah, I did the intake manifold gasket a couple of years ago and everything went fine with that, so this OUGHT to be relatively easy. But as to the replacement radiator, if I don’t go with the AC Delco and pay the $250, which of “VISTA PRO”, “SPECTRA”, “TYC” or the others “VARIOUS MFG???” have people used with success? I’m guessing some of these are Chinese (maybe even the ones with the Canadian flags). I once bought a gas tank from a company called “Spectra” in Canada … probably the same people??


I responded to you but the post never appeared. Don’t have time to re-enter it…


I’ll re-enter it before I take off … I hate this site … used to be pretty good years ago then they went to this ‘publicbroadcasting’ format which loses posts and has a very primitive interface.

What I had said was I won’t be able to see the leak during the pressure test. It’s leaking at the very bottom corner where the drain cock is. I didn’t THINK it was the drain cock, but I changed the O-Ring anyway because I was driving a long way the next day and didn’t have time to yank the radiator (ended up cancelling the trip). The drain cock had only been removed once previously a couple of years ago or so.

And I’m not in denial that it cannot be the radiator, I was just hoping it wasn’t because I really wanted to make that trip. The car is 8.5 years old. 140,000 miles is “OK” for radiator life; I got 160,000+ miles out of my '89 Colt radiator and my '97 Taurus still has its original unit (190,300 miles right now).

OK … COPY the post this time, THEN click on SUBMIT …

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…

You could try J-B Weld on it. It’s worth a shot. If it fixes it and it holds, great. If it doesn’t, replace it and be done for another eight years or so.