| Re: coolant additive
GM parts counters carry a packaged version of Bar's coolant additive TABLETS.......TABLETS......that (3) are recommended when doing a coolant change. Crumble three and place in the lower hose prior to refill and start up. GM has not stated the procedure is for head gasket problems.....it's used as a possible leak stop for hose and porous casting problems. Most of the N* head gasket problems result from old coolant allowing oxidation of the aluminum in the area of head bolt threads, allowing the metal to powder with subsequent bolt failure. The general school of thought in the threads here is to religiously maintain and change the DexCool with tablets at somewhat earlier than the recommended intervals. It can't hurt. I change the ol' green stuff in my FWC Olds 455 boat engine every 2 years, and for 9 years (knock on wood) not a problem. | 
