Hi Scotty,
All Road side mechanic say as your car engine gets old you need to change oil grade to thicker one for better protection. How true is that?
what the engineers have decided is best for your engine is better then some road side mechanic thinks.
there are very rare exceptions where this is true. (Some of the old Range Rover Diesel engines built by PSA as an example)
if you want your engine to last, change your oil and filter frequently with the OEM spec.
You are confusing engine oil Grade with engine oil Weight. The Grade is an indication of the Quality of the oil, while the Weight (5w30, 10w40) indicates the viscosity of the oil. The Weight of the oil is specified by the manufacturer based on a lot of factors, including the ambient temperature. The Grade is also usually specified. Roadside mechanics are as reliable and truthful as politicians.
