Join Date: Dec 2006
Location: Rockford, MI, USA
In a 5w-40 for example the 5w bit (W = winter, not weight or watt or anything else for that matter) simply means that the oil must have a certain maximum viscosity/flow at low temperature. The lower the "W" number the better the oil's cold temperature/cold start performance.
5 stands for oil viscosity at 0 degrees C, W stands for Winter, 40 stands for oil viscosity at 100 degrees C, that is the oil thickens as it get warmer.
'07 K1200GT Crystal Gray Metalic
'00 Ducati 900 Monster
Last edited by aj7840; Jul 13th, 2019 at 9:00 pm.