By Jim Fitch
Practicing Oil Analysis Magazine
Viscosity can go up, down or remain unchanged. The list of root causes that can alter a viscosity reading is quite extensive; hence the reason why viscosity has become such an information-rich measure of used oil condition. After all, when viscosity has not changed, you can rightly conclude that the many known viscosity-altering factors are probably not happening – a good thing for sure.
What’s not so good is when viscosity moves suddenly with no obvious explanation or warning. What does it mean and why did it occur? Let’s explore the many possible causes of low viscosity.
It’s safe to say that viscosity will not change without a forcing event or condition that incites the change. The oil analysis community is aware of the usual suspect conditions or events, but some remain undiscovered or at least are not fully understood. When it comes to an abrupt loss of viscosity or a downward viscosity movement.