Off Topic question about 5W-30 Engine Oil

Another consideration is the heavier weight oil will use more fuel than the correct weight of oil. Apparently this effect can be seen more on engines requiring 0w20 or 5w20 oil when comparred to using 10w30 in the same engine.

According to Ford, using a heavier weight oil will cause less oil pressure than a lighter weight oil on a newer hydraulic system. This was talking about the hydraulic pressure required to fire the injectors on the diesel engine.

T_Bone

Moving on to your question, another thing I have experienced is that even older cars (both my car and truck are 1987 vintage dinosaurs), 5W30 engine oil gives me less oil consumption than 10W30 oil in both winter and summer. Why I'm not sure but I do know it happens. In my old tractors, I use 10W30 but only use them in the summer months and I'd probably still use 10W30 in the winter too, somehow I think that would still be best but I'm not sure.

Bearing design loading and clearances are built around the intended oil. Thin oil for easier starts with smaller/lighter electrical systems. The thinner oil reduces internal engine windage and pumping losses = less pollution and better mileage. The early death of many small engines, particularly the splash lubricated models. Is directly due to the owner purchasing either what oil was on sale. Or using what Bubba down at the diner said to use. Like it or not, follow the operators manual. At temps below freezing a quality synthetic like Amsoil or Mobile 1 provides supperior lubrication. Other brands of synthetics are not 100% true synthetics and fall far short in performance.