AMSOIL has issued a technical service bulletin on the compatibility of GM Cooling System Sealing Tablets and AMSOIL ANT Compatibility. The issue at hand:
A compatibility question was raised regarding the use of GM Seal Tablets with AMSOIL Anti-Freeze (ANT) specified in multiple GM applications from 1982-1999 including Cadillac, Oldsmobile, Buick, GMC and Pontiac vehicles. These brands require the use of GM Cooling System Seal Tablets when replacing or topping off antifreeze reservoirs. This includes both coolant products used by authorized GM dealers and aftermarket coolants including AMSOIL ANT. The addition of coolant tablets is specified by GM to minimize the possibility of leaks in the cooling system.
The AMSOIL Propylene Glycol Antifreeze and Engine Coolant is indeed compatible with these tablets and the TSB explains the testing methods involved in determining this as well as mix ratio instructions. AMSOIL Antifreeze & Coolant is a revolutionary product that offers not only maximum protection in temperature extremes, it’s unique propylene glycol formula is biodegradable. Its low toxicity limits the threat to children, pets or wildlife. It is also surpasses standards for metallic corrosion. It can be used in both gasoline and heavy duty diesel applications and is compatible with all ethylene and propylene antifreeze and coolant formulations on the market, including DEX-Cool®, Sierra® and Zerex®. This makes AMSOIL Antifreeze & Coolant the convenient choice to serve all of your automotive, industrial and recreational applications.