Diesel engine manufactures recommend fairly low viscosity engine oil when the engine is new. As an example, John Deere Plus 50 engine oil has a viscosity rating of 0W-40. Another example, VW recommends 5W-30 for their TDI engines. I've always heard this recommendation for low viscosity oil is because of the very tight tolerances in a new engine. Obviously as an engine gets older wear happens.
I realize that other factors have to be considered for emissions purposes such as low ash oil when there is a diesel particulate filter, but I'm talking specifically about the viscosity rating.
At what point should a higher viscosity engine oil be used, or should you always use the recommended viscosity oil no matter the age/hours on the engine?
I realize that other factors have to be considered for emissions purposes such as low ash oil when there is a diesel particulate filter, but I'm talking specifically about the viscosity rating.
At what point should a higher viscosity engine oil be used, or should you always use the recommended viscosity oil no matter the age/hours on the engine?