Low coolant light & white smoke

[Ironhead]

I added 2 gallons in 2 weeks. Cant see where its leaking. Take it to dealer and they pressure test and conclude egr cooler is leaking. They say have to order the part and will take more than a week but no harm to drive like it is. With the white smoke that evaporates coming from the tail pipe, I would assume its getting in the combustion chamber. It seems I read some threads here some time ago about the detriment of water in these engines where it dont belong. Do any of you experts agree with the dealer that no harm should come from me driving it the way it is?

[csimo]

I'd be very careful in your situation. It takes very little water to damage a diesel engine. If you see white smoke (steam) that's too much. When the engine is shut off you get condensate in the cylinders, and more water from residual pressure in the coolent system. Very little water will result in hydraulic lockup of the engine.

I don't agree with the dealer at all that it's OK to drive as is. I would call the GMC/Chevy assistance ASAP. You could be doing damage that won't show up for years.

[Redhawk]

Ironhead, ditto on the hydraulic lockup. I had the same problem with an 89 Ford diesel. White smoke and coolant loss. It took a lot to kick over the engine, almost like a dead battery. That was a clear sign that hydraulic lockup was not too far away. Turned out to be a head gasket. Get better dealer help/advice right away. I hope this is all a false alarm, but better to know for sure.