: 96 DeVille losing coolant



djm
10-06-05, 02:37 PM
My 96 DeVille is losing coolant. There is not evidence of leaking on the ground or under the hood. It is not overheating. I had it pressure tested and it shows no problem. The mechanic, who has been reliable on all my cars, is very puzzled.

I've read about pellets, however, wouldn't a pressure test expose a leak that would be fixed with the pellets?

Any suggestions,

DJ

davesdeville
10-07-05, 03:24 AM
All the pellets are for is tiny little fissures/pits that happen around the gasket surfaces when the aluminum is exposed to hot coolant and starts corroding. The bars leak sealant particles seal the fissures to prevent them for corroding further and causing a problem.

How much coolant are you losing anyway?

djm
10-07-05, 09:36 AM
About a pint a week. Just enough to activate the Coolant Level Low message.

DJ

mcowden
10-07-05, 12:11 PM
About a pint a week. Just enough to activate the Coolant Level Low message.

DJ

You might have a pinhole leak in a hose that's too tiny to be seen and only leaks when the system is under pressure (i.e. while driving). That would explain why you don't see any puddles. It could also be the water pump bearing. They leak sometimes, and mine only leaked when the pump was turning and the system was under pressure, so I had no puddles either. The water pump cover gasket has also been a sore spot for some, and I also had to replace the gasket on mine. When that gasket gets replaced, the cover has to be carefully and thoroughly cleaned of any sediment, deposits, debris, etc., so the gasket seals against a clean, flat surface. Otherwise you're wasting your time. If it's the water pump bearing leaking, the water pump needs to be replaced. To find the pinhole leak in the hose, get the car up to full temperature, as in drive it for 20 minutes or more, then leave it running, open the hood, open the throttle a little bit (by hand), and look around carefully. When I had a pinhole leak, it was on the bottom side of the upper radiator hose, way back in the corner, and it was aimed away from your line of sight, so the only way to see it was to look at it from underneath the car or roll the hose over a little bit to see the drip.

A few thoughts anyway. If your mechanic didn't know or do any of these things, it's probably time to find a new mechanic. I'm a computer guy and I figured this stuff out by myself before I ever joined this forum.

Let us know what you find and how you get it resolved. Good luck...

Ranger
10-07-05, 06:19 PM
Also check the surge tank. I recently had a hairline crack at the purge line nipple that was absolutely undetectable til coolan was flowing. Others have reported cracks on the underside. Dried Dex-Cool however does leave a whiteish telltale residue.

zonie77
10-08-05, 12:38 AM
A small leak in the heater core can be very difficult to find.

djm
10-17-05, 10:30 PM
Finally, there was evidence of a leak. I took it to the shop that overhauled the transmission because I thought the reddish fluid might be transmission fluid. They said it was coolant coming from the vicinity of the water pump. However, when they started removing components, they said it was originating at the head gasket.

I had him put pellets in as a temporary measure, but am planning on replacing the car in the next day or two (with a Toyota Camry). $3200 for a head gasket/timesert job doesn't seem to make sense on a car worth about that much.

Thanks to everyone for the advice.

Jesse

davesdeville
10-18-05, 02:43 AM
It's too bad more people won't do any serious work on their own cars...

blb
10-18-05, 09:17 PM
.

blb
10-18-05, 09:19 PM
Finally, there was evidence of a leak. I took it to the shop that overhauled the transmission because I thought the reddish fluid might be transmission fluid. They said it was coolant coming from the vicinity of the water pump. However, when they started removing components, they said it was originating at the head gasket.

I had him put pellets in as a temporary measure, but am planning on replacing the car in the next day or two. $3200 for a head gasket/timesert job doesn't seem to make sense on a car worth about that much.

Thanks to everyone for the advice.

Jesse

Jesse,
I think you made the right decision in the long run. Good luck with the new wheels.