Okay, I've got a dandy for you. My wife's 2004 Grand Prix has started leaving an anti freeze stain in the driveway. My first thought was the water pump. I looked all over around the water pump pulley's etc. Dry. Even the plastic tray under the compressor was clean.
I noticed the over flow tank was low and full of Dexcool crud. I've had bad luck with that stuff in this car. Two years ago I got the PO128 code and the thermostat was stuck open. I replaced it and drained the anti freeze and refilled with fresh Dexcool. Mistake. I should have replaced it with universal anti freeze. I did last weekend. The thermostat was stuck for the third time and kicked out the PO 126 code. The inside of my radiator looked like somebody deficated in it. I flushed it with radiator flush, cleaned out the over flow tank, flushed the system out again with water, and filled it with Peak Global anti freeze.
Now for that leak. I got the car off the ground started it and looked all over for a leak. It seems to run along the seven-inch wide unibody beam that is below the starter and runs to the body mount. The stain is below the overflow tank. It makes me think that the tank ran over and dumped out the drain tube at the top of the tank, or there's a crack. The tank seems dry though. The leak seems intermitent and slow. I checked with my mirror and found the recently replaced coolant elbows are not leaking. I managed to see what looks like a sending unit in the block was dry. I almost want to think the coolant is running out of the front engine mount located below the front of the oil pan. That can't be.
It's a tight fit. I want to rule out the water pump because if it leaked the weep hole would gush enough coolant in its area that it would be hard to miss. The expansion plugs I could see seemed dry. No hoses in the vicinity were leaking.
Could an intake manifold create a subtle leak, or would that be a steamy gusher? The oil is good, so it appears to be an external leak here. I didn't see any seepage around it, but I should go to a car wash and clean it off and look.
Any ideas? I'm going to keep crawling under it. I need to replace the front brakes so with the wheels off maybe I can see something in the passenger wheel well near the water pump area.
