Coolant leak, and effect of driving with temp gauge in red zone

[guitarfish]

This is a little long, bear with me, I need some help.

10 days ago my son is driving to work in his 97 GP 3800 (no SC). (130K miles, very well taken care of). The pulley busts off the idler tensioner, the serp belt falls off. He turns around and drives home. The trip home is about 15 minutes. At about 3 minutes into the trip home, the temp is in the red area of the gauge. You and I would shut the car off, but he didn't.

It was 10 degrees out, and he says he coasted often, and the needle went back and forth between full red and just below red. The last 1/2 mile or so before he gets to the house, the engine is starting to run pretty rough (he described it as sounding diesel-like). Finally home, he shuts it off. Of course, I'm not told about this up front.

I replace the idler pulley, but I also see power steering fluid dripping out at the PS pump seal, so I had to replace that too. Once back together, everything seems OK.

A week goes by, and his low coolant light comes on. There's coolant all around the water pump, I can't tell exactly where it's coming from, but I'm pretty sure it's the pump, so I replace it.

It's been 2 days, and we're still losing coolant, about a two cups per day. I see some coolant around the water pump gasket. (I used blue RTV silicone sealant on both sides of the gasket when I installed the new WP). I am not certain if it's coming through the gasket, or if in fact it's coming from somewhere else, and just landing/collecting on top of the WP.

Now I find out about the high temp drive last week, and I'm in panic mode. Is it possible something more serious is wrong, such as a head gasket, or cracked head, etc?

The engine oil dipstick shows no bubbles and seems to be pure oil. I used some foaming engine cleaner around the WP area tonight to clean things up and hopefully get a better idea where the coolant is coming from.

SO...

-Comments on the high temp, and possible damage?
-Does it sound like it just might be a bad install of the WP gasket?

Thanks guys

[BNaylor]

I'm assuming you gave your son a good stern lecture especially if you are footing the repair bill. It doesn't sound good. I'm surprised he made it that far on battery power.

On the coolant around the water pump does it look like it is residual or an active external leak? I would check the areas around the UIM plenum and lower intake manifold. Another area would be the 90 degree plastic coolant elbow leaking from the main tensioner to the lower intake manifold.

Head gasket is a possibility but so are the UIM and LIM gaskets. Hopefully there is no internal engine damage like pistons/rings, connecting rod/camshaft/crankshaft bearings or valvetrain.

[guitarfish]

Well, I ran the car tonight for about 25 min until it was nice & warm, then pulled it in the garage for an oil change. The area all around the water pump is bone dry, I don't believe it's leaking anywhere there.

However, under the engine, on the steel frame piece that supports the engine, there is a puddle of coolant that has collected there, on the pass side. Underneath the car I can see drops of coolant along the front right part of the u-shaped steel support.

I found the 90 degree plastic elbow water bypass pipe - no leaks there. The leak seems to be down low on the engine - a freeze plug, perhaps?

I think the next step is put it up on ramps and try to find the source. Any thoughts would be appreciated.

[guitarfish]

PROBLEM FOUND !!!

A friend came over tonight, we go out to the car, which has cooled for a few hours. First thing he does is reach in and squeeze the bottom hose repeatedly, and you can hear squirting noises. Holding the flashlight, I can see coolant mist in the light. Survey says: it's the 90 degree coolant bypas hose. Ding ding ding!

Never saw it coming out of there, I was always checking when the car was warm. Lesson learned. Thanks all for the help.