K&W block seal

well this one is somewhat unique in that you have to drain all antifreeze (flush until clear water) and then let the product circulate for 30, then you drain whats left of the product and let whats left 'cure' for 24 hours. They even tell you to remove the plugs (and unplug injector) in the suspect leaking cylinder (.."if your cylinder is leaking water, youll notice a orange glaze on spark plug tip..") and idle the beast with that plug removed! Then its button up, put your stat back in and refill with coolant without a flush. Id suggest you drain it at the block taps because I suspect it will become hard-block if you just drain the radiator. Well see this afternoon. They had a product called "Blue Devil" that was $65 a bottle, pretty much the last resort pour in fix. I think the used car salesmen buy that stuff by the barrel.