I recently watched a lot of youtube, and here's what I learned:

Sta-bil is probably the best fuel stabilizer (actually I already knew that having had very good success with it).

Hot Shot's is probably the best diesel additive by a lot.

Do use fuel additives such as fuel system cleaners.

DON'T use oil additives, except maybe a flush product minutes before an oil change and without driving with it. Oils are already specially formulated to perform as best as possible for whatever specific application they are designed for.

Don't frequently change the brand/formulation of oil, as different formulations can fight with the residue of the last one causing worse oil performance. This is the same reason to not use additives.

Don't use diesel oil in gas engines (women would never do that) or gas oil in diesels; the oil manufacturers know more than you about what works best in what, and doing otherwise really could be catastrophic in a few engines.

Amsoil Signature Series is the best there is in my opinion because it ranks lower high to upper middle across many specific tests and use purposes, which means it is not necessarily best at any one thing, but is plenty good enough at everything. It's an above average average oil such that using another formulation could compromise performance/protection in some areas while improving in others.

Don't use new oil that has been stored for many years (beyond 3-5 years). The fresher the better. Even sealed new oil can degrade, absorb moisture, and oxidize, significantly losing it's ability to protect the engine.

Do make sure the cap is tight on on your unopened oil, and store it on an upper shelf in the house (where it stays warm and the AC keeps the humidity down). Cold, and sitting for years, can cause the built-in additives to separate out, which are not easy to mix back in (shaking the bottle does almost nothing). Old oil still works, but is it worth shortening the life of an engine with as expensive as they are now?


Finally, there is no such thing as Lifetime Fluid. Antifreeze, Brake fluid, Transmission fluid, 20,000 mile motor oil all must be changed regularly and probably much more often than your car dealer recommends, if you want the systems those fluids go in to last more than just 150-300k miles. They attract moisture causing rust, change PH and become corrosive, break down or fill up with suspended sediment that becomes abrasive.

The cause of oil consumption in old engines apart from leaks is probably due to not just regular wear, but the oil rings on the pistons, which have a hard life with little oil flow, getting clogged with sludge, and failing to deliver oil to the cylinders. Sludge comes from old oil getting baked on. It's an indication of excessive heat or mainly not enough fresh oil with fresh detergent is flowing through that area. These lower oil rings may be one of the only places with any indication of sludge due to the harsh conditions they operate in.

A solution would be to use oil with a particularly strong cleaning ability, and changing it every 5k or less, with an occasional detergent engine flush. Sludge can start as soon as 20-30k and get severe enough to cause harm around 60k.