You want to know what the deal is with ZMAX? Here it goes:

"The US Federal Trade Commission has filed suit in U. S. District Court seeking to halt false and misleading advertising for ZMax auto additives and has asked the court to order refunds to all consumers who bought the products. The agency alleges that enhanced performance claims for the product are unsubstantiated, that tests cited to support performance claims actually demonstrated that motor oil treated with ZMax produced more than twice as much bearing corrosion than motor oil alone, and that the three different products - an engine additive, a fuel line additive and a transmission additive - were all actually tinted mineral oil. zMax is manufactured by Oil-Chem, a wholly-owned subsidiary of Speedway Motorsports, Inc. ''
You really want to try it??
JackD