Synthetic In High Mile Engine?

The molecules of air are smaller than the molecules in the oil. If the gaskets and seals are air tight in your motor, which they should be, you won't have any leakage difference from one oil to the other. The only advantage to petrolem based oils are they are cheap, this would be the only advantage. If you want the best of both worlds use a synthetic blend, they are reasonably priced and still have some of the synthetics desirable properties against breakdown and anti wear. If you count the longer mileage you can achieve between oil changes the synthetics become more inexpensive to use. The company I purchase my sythetic oil from do oil analysis for me at oil changes and from that, get recommendations on change intervals. On a '96 Bronco I had it went up to 10,000 miles between changes. If you do the math of purchasing synthetic oil & filter once every 10,000 miles and purchasing petroleum based oil and filter 3 times in 10,000 miles I am money ahead, so the low priced advantage is now gone. This Bronco had 178,000 miles on it when I sold it and was down only one quart at oil change (10,000 miles). The trans, transfer case and diffs also had synthetics in them and they were the original.


Chuck