The previous topic on finding a good diesel 15w-40 synthetic got me thinking. Why do they make a 15w-40 synthetic? In comparison to a 5w-40 synthetic (forget fuel savings advantages)...does the 15w-40 synthetic offer any advantages as compared to a 5w-40 synthetic?
Mobile Delvac 5w-40 Synthetic Amsoil 15w-40 synthetic
cSt @ 40ºC 98 103.2
cSt @ 100ºC 14.7 14.6
Viscosity Index, ASTM D 2270 156 146
Sulfated Ash, wt%, ASTM D 874 1.0 1.0
Total Base #, mg KOH/g, ASTM D 2896 10.1 10.4
Pour Point, ºC, ASTM D 97 -48 -40
Flash Point, ºC, ASTM D 92 249 238
Why would one run one or the other? Thanks.
Mobile Delvac 5w-40 Synthetic Amsoil 15w-40 synthetic
cSt @ 40ºC 98 103.2
cSt @ 100ºC 14.7 14.6
Viscosity Index, ASTM D 2270 156 146
Sulfated Ash, wt%, ASTM D 874 1.0 1.0
Total Base #, mg KOH/g, ASTM D 2896 10.1 10.4
Pour Point, ºC, ASTM D 97 -48 -40
Flash Point, ºC, ASTM D 92 249 238
Why would one run one or the other? Thanks.