Oil Data Sheets provide information about the quality of the lubricant. ; ;One of the key numbers to look at is the NOACK number. ; ;The Test is standardized as ASTM D5800. ; The NOACK number is the percentage of evaporation that happens in 1 hour when held at 250 degrees. ; It's a good measure of heat resistance and the ability to perform under extreme conditions. ; The more a motor oil vaporizes the thicker and heavier they become, contributing to poor circulation, reduced fuel economy, increase oil consumption, and excessive wear and emissions. ; A maximum of 15 percent loss is allowable to meet the API SL and ILSAC GF-3 specifications. ; ; Interesting tidbit; AMSOIL Inc was the first Oil Company in the United States to use and report NOACK results in 1984. ; ; Most oil companies list this information on their data sheets, but some do not. ; These are not made up numbers, they are ASTM tests that companies pay to have done. ; If oil companies do not publish this information it is likely out of embarrassment or it shows their flaws. ; The Lower the number the better. ; AMSOIL Signature Series 5W-20 has a NOACK volatility number of only 5.8. ; ; Another oil I just researched for a customer has a NOACK Volatility number of 13.7! ; ; Remember that is the percentage of evaporation that happens in 1 hour when held at 250 degrees. ; 13.7 may meet the minimum spec but when operating in a commercial environment in extreme conditions of heavy use, pulling heavy loads, with hundreds of thousands of dollars invested in equipment why chance it with an inferior oil? ; AMSOIL provides the extra protection needed to keep equipment running and out of the shop with repairs. ; AMSOIL Signature Series Oils for Gas and Diesel vehicles are designed in the lab and over engineered to provide the absolute best engine protection