What makes AMSOIL different from other synthetic oils is the base stock used pre-production. Brands like Motocraft, Pennzoil and other common brands use what is known as a Grade 3 base stock oil as the base for their formulas. Base stock grades are rated from 1-5. Royal Purple begins it's life as a grade 4 base stock oil. Mobile 1 USE to begin it's life as a grade 4 base stock oil, but back in 2007 when Mobile issued a complaint about Castrol making full synthetic claims while using a grade 3 base stock, Mobile was told by the governing body that received the complain that oil companies have free rein to make whatever claims they want about being synthetic since the word synthetic is a broad based term. So Mobile changed their base stock formulas and began using grade 3 base stocks to save money. Hence why you can now find Mobile oil for so cheap at Walmart and other places.
AMSOIL uses a grade 5 base stock and is one of a very few oil companies that does so. Their oils are formulated to exceed manufacturer specs for engine oil. But you have to use the correct oil for the application. With some brand vehicles, it takes more than just the weight of oil matching the requirement to meet the manufacturer requirements. They offer several different levels of quality in their oils, from their OE oil that is basically meant for your OEM recommended oil changes, their XL level oil that is a little better and their Signature Series oil that is formulated for extended intervals, which, when using their oil filters, are guaranteed for extending intervals to up to 15K miles or one year with severe duty service and 25K miles under normal driving conditions.
THAT being said; I never recommend anyone extend intervals THAT long without utilizing
used oil analysis (UOA) to help determine if extended intervals are right for your vehicle and driving style/conditions. It can also help to warn you of possible issues going on in your engine.
AMSOIL also offers another benefit with their
Preferred Customer Membership program. This membership, for a small annual fee, allows the average Joe to order AMSOIL at factory direct wholesale pricing and have it shipped directly to them for their convenience. Preferred Customers pay the exact same price that dealers like myself pay when ordering. That can amount to up to 25-30% savings on your annual maintenance on your vehicles.
For me personally? I began using AMSOIL in 2006 at the recommendation of a friend that owns our local Carquest auto. He touted extended intervals, etc. But being a user of Mobile 1 at the time, I was slow to make the change. When I did, I still changed my oil every 3k miles until I began using UOA for testing my oil for extended intervals (also by recommendation of my friend). I began testing originally on a 2003 Duramax and my first tested oil change went over 20K miles testing every 4k miles and according to the lab, there were no wear metals present, the viscosity and TBN (Total Base Number) of the oil had not changed. I changed it to test another oil, but wound up going back to the original (diesel & marine oil). Since then, I have only had one vehicle that had issues with it and I honestly think it had issues with the engine right from the start. That vehicle was a 2008 Kia Sportage that I purchased brand new off the showroom floor for my wife. Right from the start, no matter what brand oil I tried, it would burn it up within 2K miles and leave crusty varnish on everything inside the engine.
