The only people that I know that use Amsoil and also notice a significant drop in oil temperatures verses other oils is Harley Davidson owners that have a temperature probe/oil dipstick. These are air-cooled, large displacement motorcycle engines, and seem to benefit from using this synthetic oil, dropping oil temps by about 20 degrees F. I know a couple guys who will not put any other type of oil in their bike engines, but will put Castrol GTX in their car and truck engines and be satisfied.