Quote:

---

Quote:

---

Quote:

---

Quote:

---

Now to rile up the arm chair quarterbacks, the facts by Shell oil engineers state that the oil gets acids in it when it sits after being ran. This occurs when the by produces of combustion and the moisture mixes within the crank case is converted to acids and they will start to eat away at different parts of the engine. 6 months on an oil change helps prevent this on an engine that is occasionally driven. The only way to prevent this is to get the oil temps up to 140* F for an hour to evaporate the moisture each time you run the engine.


Also oil does have a problem after it sits, when the manufacturers put the additives in, they do it at specified temperatures, typically they can begin to fall out of suspension within the oil after 4 years. It may not always happen in 4 years but manufactures have tested and proven it WONT in the first 4 years. Only testing can demonstrate whether they have or not. For the cost of a case of oil, I will use only fresh. Tim

---

So if the "additives" settle out, it would seem they could also be just as easily re mixed, with little harm, maybe just shake you motor thoroughly before starting after sitting.

---

No matter where the additives are, when you pour the oil into your motor the additives are going with the motor oil and they will mix just fine if it is even a concern. lol

---

Uhmmm NO they wont. But all of the chemists on here would know that...that's like saying that if you soak your cooked bacon in bacon grease, the grease will go back into the bacon...when you put it back into the fridge. Do what you want, you will anyways, but I do know that it is an FAA violation if you put expired oil in an airplane, there was an airline who flew piston powered airplanes had several engine failures because they were using 15 year old oil. Shell tested it and found that the additives (detergents) separated causing bearing failures.

---

Quote:

---

The chemical processes are the same to add the detergents to the oil. I was using it as an example, airplanes use 1930's tractor technology because tractors were more advanced than automobiles during its infancy. If someone was to have a bad engine, it would either go to the scrap yard or be rebuild without ever being investigated. Its a proven fact that oils do get old and change chemically, but you will still have those who will claim that their oil is good and they will use it anyways.

---

It maybe a proven "fact" that oils change oil time, but no one has proven that here. Only consensus so far I see is additives, settle out, but again no one has proven whether its a chemical reaction to include the additives in the original oil, nor whether it's a chemical reaction that causes the non reversible settling of the additives. And if some one can find one single obscure offball proprietary no name additive that reacts, and decomposes, I likely would not consider that proof of the main premise.

And regrading the example of "SN" oil, it was an example, hence the use of the word "like", I have little knowledge of aircraft oil classifications, mil or otherwise, and was mentioning the classifications/specs also likely change over time, and the 15 years others mentioned, was enough time for the classifications to change, causing the oil to be obsolete, but not really old.

So teach me.