Have you seen these commercials

Shell has lost a large share of market to the semi synthetic(and are NOT really) oils that are hyped in auto magazines at trade shows and in garages. I prefer Rotella in my machines but also like DELO which is Chevron.


As to my note above, look up Synthetic Engine oil, the tell all is these oils are just reformulated standard petroleum products, 'Enhanced' by that reformulation. None are a True Synthetic, ALL are based on petroleum base stock even if hydrocracked which is hyped as then synthetic.


I as a mechanic do NOT believe in extended interval oil changes. I can see NOT changing oil at 2500 or 3000 miles as the oil really is not broken down by then as My own oil industry grandfather noted. He worked at Standard, they NEVER changed oil just spun on a new filter and added makeup oil but they only kept machines five years. Truth is acids, contaminate particles and the exhausting or volatizing of oil additives happens over a short period of time. Rotella has a great reputation but has changed formula over the years, they ALL have. Oils have Better additives these days and most eliminated Ash content as that was the major source of crud build up IF you did not change often enough, ash was a lubricant additive so long as remained in solution. Oil changes CAN be extended in low stress work such as long term straight line continuous runs under light load. High weight load, multiple engine rpm oscillations(shifting), extreme heat or cold changes all that. Sitting in traffic is the absolute highest stress element of engine oils with pulling long grades or working at excess high hp load conditions as second.


IF you insist of extended service intervals to be expense controlling then rotate your cars more often that is trade off the old one at five six or seven years and begin the program again on the next one as at some point in time the extended intervals will let you down. My Ford SD 7.3 diesel gets oil twice a year due to acidic build up and sedentary life. My AC 7G crawler by either extended use (figured at 40 hours worked) or annually as it does sit considerably. My other engines without hour meters or documentations as the oil appearance tells me is time. Dark, dirty to excess, thin feeling off the dipstick are still Good evaluation considerations. Large engines CAT will accept oil samples to examine and test for a fee, not cheap but worth it on older machines. Most times the reports which do NOT have access to the machines miles will note time to change around the 10-15,000 mile mark, 10K used to be a industry standard for Highway machines years ago. The 20-30-40,000 mile interval on Special Manufacturer oils with the 'Written Guarantee' is as worthless as that guarantee when you try to recover it.

And NO, I have client used and will NOT personally use AMSOIL, my own choice with previous customers that demanded the use in their equipment, is a good oil, I just do NOT buy the hype as have seen too many engines internals on it with changes extended TOO FAR.