AMSOIL stands behind all of their products for as long as you use them, meeting and or exceeding manufacturers specifications. It is in fact illegal in Canada and the USA to connect warranty coverage to a particular brand of oil / lubricants / parts you use. If this is the case your manufacturers should provide the parts or lubricants free of charge to you. You have every right to choose the products you want to use including products like AMSOIL that are formulated to extend drain intervals. Manufacturers that deny warranty coverage must show you evidence that aftermarket parts or lubricants caused a failure. Click Here tor Learn More About AMSOIL.