Originally Posted by rkramer
some head gasket sealants DO work, but are never a permanent repair. Its more of a stopgap to allow you to enough time to trade the car in to a dealer for a new one... (I have no problem trading in a $1000 car with a blown head gasket to a dealer, but I'd never sell one like that outright to an individual without disclosing it.)
I'm a former Honda dealer mechanic before working my way to becoming a UPS diesel semi mech. We used block sealer as a last resort a few times at the dealer. It was for unfortunate customers who couldn't afford a proper repair on low value cars. Surprisingly, it worked. if you don't drain the coolant and use water, don't bother. You cant paint outside in the rain, so dump your coolant and do it right.