Can anyone answer why I can use for the last few years Mobil 1 Delvac 15W/40 Diesel oil in 4 cylinder, 6 cylinder and 8 cylinder cars with no issues and no MPG loss?
I decided to do an experiment on an older 4 cylinder car of mine after reading an article about a guy who has studied MPG improvements for 30 years. He recommend 15W/40 for all cars.
Right now I am using 15W/40 oil on my 6 cylinder Ford Freestyle and have been doing so for the last 3 years. Also I used it on a 8 cylinder Ford E350 before I sold it to upgrade (or downgrade) to the Freestyle.
I have wondered for the last few years if these oil viscosity recommendations that vary from car to car is nothing but a money making gimmic for the oil companies?
I decided to do an experiment on an older 4 cylinder car of mine after reading an article about a guy who has studied MPG improvements for 30 years. He recommend 15W/40 for all cars.
Right now I am using 15W/40 oil on my 6 cylinder Ford Freestyle and have been doing so for the last 3 years. Also I used it on a 8 cylinder Ford E350 before I sold it to upgrade (or downgrade) to the Freestyle.
I have wondered for the last few years if these oil viscosity recommendations that vary from car to car is nothing but a money making gimmic for the oil companies?