2001 Chevy Silverado with a 5.3 L engine and a leaking head gasket that was getting worse (at 217,000 miles). Car has rusted body (upstate NY), so not going to spend too much for repairs. Decided to try one of those “magic elixors” in a bottle. Went for the Bars Leaks head gasket repair stuff - 16 ozs. cost $35.00 plus tax. Followed directions, etc (put it into the top radiator tube, NOT the overflow bottle). The stuff had little strings of copper-looking stuff floating in it.
Long story short - it worked. After a little more loss of coolant, the coolant loss has finally stopped. Amazing that something like this really worked.