Wanted to give a followup on a leaking head gasket on a 2001 Silverado with 5.3 engine. It kept using more and more coolant until I was putting in over a quart every tank of gas. With over 200,000 miles on the truck, I really thougth it was worth the try of one of the magic elixors Tom and Ray talk about. Tried Barrs Leaks for head gaskets - cost about $35.00 - it looks like there are all slivers of bright copper in the solution.
Put it in about a year ago and it really did help. It still uses a little coolant, but more like a pint every 2,000 or 3,000 miles now. I can live with that as the truck is nearing rust bucket status.
Thought people needed a good outcome for a change.