There has been in the past a lot of descussion aboute synthic oil and what it will do for extending the life of the engine? how does one judge what is the best? Example for the last 20-30 years I have always used Kendall Super D oil in my diesel vechiles Each of which have topped the 200,000-300,000 miles never had an engine failer that could be traced to lubercation.I always chainged oil at 3500-5000 miles. I have had people tell me that that brand of oil is not realy the best.It works for me. I mention this to the Kendall destruter and we descussed oil His openion thet with reguler oil changes a good protilum based oil will do the job Ok. he did reccomend that synthic oin be used in the transmition as it is much more tolerant to overheating 6that often occurs in auto transmitions.
The other side of the conin is I had a little GMC 1/2 ton pickup with a 250cid engine which was often overloaded and pushed to the max. I bought whateaver oil that was on sale at K Marit or other discount houses. Chainged regularly and at 275,000 miles a exaust valve stem broke and finished the engine. at that time it useh a qt between changes. So now tell me what is good oil
Jim Smith
1965 Tradewind(the Silver Abal;tross)
1992 Dodge Cummins Diesel