More than likely your intake manifold gasket is shot.  You won't find any
indication of water/coolant in the engine because it is being burned up.
This settlement will help pay for some of the repair, but not nearly enough,
IMO.  http://www.gmcanadiansettlement.ca/english/eng_home.htm.  Tell the
mechanic that does the repair to flush the Dexcool completely out and
replace with something better, like Prestone.

"Fred Mayfield" <> wrote in message news:

It is common for the intake manifold to leak.
It mostly leaks to the outside of the engine, not
in the intake/combustion canals, nor into the
crankcase.  If your Mom's car doesn't need coolant
very often, just fill it, not fill the resevoir, fill to
couple inches from the top.
The way I fixed it on my Malibu is with 'Bars Leaks
Heavy Duty', which you can get from any auto store.
I disconnected my top radiator hose and poured a little
out and then added the Bars Leaks.  I had been topping
off my resevoir, as the other poster says, with regular
antifreeze, not the Dexcool stuff, but that became
worrisome, so I fixed it.
Some will insist to have the intake gasket replaced, but
that will just result in the same problem over time.
The Bars Leaks is a very old, but good fix for minor
coolant leaks.  It doesn't clog the system, it only hardens
where it hits air.
A more complete job would be to drain the coolant
entirely and then add coolant and Bars Leaks, I guess.

i know pontiac had a recall for dex-cool lll eating the PVC intake gaskets
the fix would be an expesive new rubber gasket. get the VIN and call a chevy
dealer (service dept.) and ask them.