Cadillac Repair: Antifreeze, seal tabs, gm engineers

Question
I have a 1990 Cadillac Deville with the 4.5L V8 engine. It has the aluminum engine and the manual recommends adding the GM sealant additive when changing the antifreeze. Can I use an aftermarket sealant like Bar's instead? If so, which particular version do you recommend as there seem to be several kinds. The coolant in the car now is green and if I do a thorough backflush, can I use the 5/150,000 extended life coolant? Thanks, Robert

Answer
Hi Robert, If the bars is in pellet form then maybe it might be ok. GM engineers did a study and issued a major recall to install the GM brand seal tabs because they work. Other things may work as well or better but is a $5,000 engine job worth the research and development on your part if the Bars doesn't seal propperly? The GM recommended seal tabs aren't that expensive...buy the 6pack from the dealer and have peace of mind. As for the anti-freeze GM engineers say that if green anti-freeze is put in with Dex-cool then the engine is contaminated and you will be flushing every 2 years. I would read the bottle and follow the recommendations of the manufacturer. So if say Prestone says you can flush and then add the extended with no adverse problems then that is what I would do and use. Bill