[hurryinhoosier62]

Originally Posted by 78w72

Same here... sometimes 1 or 2 of my cars dont get driven much for whatever reason, working on them or on something else, its hard to put lots of miles on multiple cars sometimes living in the midwest with a shorter driving season than those in year round warm climates.

If i have less than ~1000 miles on the car for the season I dont change the oil, its a complete waste, oil doesnt go bad sitting in the pan (or bottle) in that short of time, same for the filter. If the engine is healthy & not dumping raw fuel into the oil or other major issues like that, the additives neutralize any combustion by products and the anti wear additives dont go bad while sitting. My engines are clean lower mile rebuilds so no high mileage sludge or anything.

I also spoke to valvoline about long term use & was told the same thing, 1-2 years at low miles is not an issue at all, neither is new oil in the bottle for 5 years or more if stored properly. I have & use oils rated SN & SM & even some 15+ year old rotella-T SL grade.... stored in climate controlled area off the ground, shake them every year or so & again before using.

Valvoline FAQ- "DOES MOTOR OIL EXPIRE? IF NOT, HOW LONG DOES MOTOR OIL GENERALLY LAST?
Valvoline motor oils do not have documented expiration dates. When stored under optimal conditions, the product remains stable for an extended period of time. It can be used as long as the American Petroleum Institute (API) rating on the label continues to meet or exceed the requirements listed in your car’s owner's manual. If the rating is still current, we advise you shake the container before use to blend any additives that may have settled."

Combustion byproducts in oil have a nasty tendency to turn acidic in the presence of moisture. I’ve seen it in aircraft recip engines and classic automotive engines as well. Changing the oil is cheap insurance to prevent acid damage of internal engine components.

[Formulajones]

That's why I mentioned the oils formulated to those specific situations of sitting for long periods. That meant in the engine and have been run to some extent. As you said they get vary acidic and cause corrosion etc...

The article quoted above is referring to oil sitting in its original container. Completely different scenario.

Just making sure people are aware of the distinction so there is no confusion

[78w72]

Originally Posted by hurryinhoosier62

Combustion byproducts in oil have a nasty tendency to turn acidic in the presence of moisture. I’ve seen it in aircraft recip engines and classic automotive engines as well. Changing the oil is cheap insurance to prevent acid damage of internal engine components.

Yes im aware of combustion byproducts and acids etc... there are additives in all oils that neutralize them, with lower miles as mentioned, the additives do what they are supposed to do... theres no difference from sitting for a short time with lower miles than driving the car to reach the maximum miles before an oil change, if anything taxed oil at the end of its life has more acids in it and is exposed to more moisture from starting & driving. Clean low mile oil is perfectly safe to sit for a few months during storage or a full year. Valvoline confirmed this when I asked.

Originally Posted by Formulajones

That's why I mentioned the oils formulated to those specific situations of sitting for long periods. That meant in the engine and have been run to some extent. As you said they get vary acidic and cause corrosion etc...

The article quoted above is referring to oil sitting in its original container. Completely different scenario.

Just making sure people are aware of the distinction so there is no confusion

The valvoline article/FAQ was quoted in regards to new oil in the bottle, as I mentioned I have/use older but new oils all the time without issue, and there are lots of people out there with stashes of older oils older than 5-8-10 years.

Some people seem to think new oil goes bad sitting in the bottle for a few years so I quoted the info. Some also think clean oil with lower miles in the engine for ~1 year goes bad and needs to have a special additive package... but then again some think they need VR1 racing oil in their stock cam engine, none of that is true or based on any scientific proof. Valvoline as well as many mechanics I know have said low mile clean oil is perfectly fine to use after 1 year, and based on my experience of doing that for 25+ years theres is nothing to indicate otherwise.

[Formulajones]

Yes but that's not what I was referring to when I mentioned oils formulated for sitting. I was talking about oils already in an engine and the car just sitting for long periods. There are oils formulated just for that purpose that fight against the moisture and corrosion that happens in those situations.

I just wanted to make that more clear in my second post because it seemed my first post was being misunderstood.

[tjs72lemans]

I've always tried to change my classic cars at the 2500 mile mark regardless of time. Unfortunately, it turns into many years. Now, knowing better and educated on acidic issues sitting in the oil pan and bearings make me change more often. Never an issue though with some I've treated that way for 40 years and tens of thousands of miles. Also in an environment like MN, they sit for up to six months at a time. But, sit they do. No starting just to warm up.
With this being my first Pontiac and a fresh expensive build, I wanted to change the oil sooner. I guess my 3 year and 2100 miles wasn't soon enough. When I start it, I drive it. No start just to warm and shut off. This time I thought I was changing it a bit sooner, but that was because I wanted to make sure any build residue left from the 500 mile oil change got dumped sooner. Looks like I may change it sooner this time to see what a new analysis looks like. I have 800 miles on new oil now, so it will probably be next year. I remember a post where one individual claimed he does the analysis so he's not wasting money on oil changes that aren't needed. I feel like my analysis says I'm not changing it soon enough. It doesn't tell you that. You have to read into it.

[hurryinhoosier62]

Originally Posted by 78w72

Yes im aware of combustion byproducts and acids etc... there are additives in all oils that neutralize them, with lower miles as mentioned, the additives do what they are supposed to do... theres no difference from sitting for a short time with lower miles than driving the car to reach the maximum miles before an oil change, if anything taxed oil at the end of its life has more acids in it and is exposed to more moisture from starting & driving. Clean low mile oil is perfectly safe to sit for a few months during storage or a full year. Valvoline confirmed this when I asked.



The valvoline article/FAQ was quoted in regards to new oil in the bottle, as I mentioned I have/use older but new oils all the time without issue, and there are lots of people out there with stashes of older oils older than 5-8-10 years.

Some people seem to think new oil goes bad sitting in the bottle for a few years so I quoted the info. Some also think clean oil with lower miles in the engine for ~1 year goes bad and needs to have a special additive package... but then again some think they need VR1 racing oil in their stock cam engine, none of that is true or based on any scientific proof. Valvoline as well as many mechanics I know have said low mile clean oil is perfectly fine to use after 1 year, and based on my experience of doing that for 25+ years theres is nothing to indicate otherwise.

Not really. I have seen both cranks, cams and bearing pitted by acidic oil in engines that were not warmed up long enough to burn the acidic compounds or the moisture out of the oil. And yes, oil for aircraft piston engines, diesel engines and classic automotive engine allegedly have these “acid neutralizing compounds” in them, but in my 6,000 engines of experience I have seen few engines that were stored long term that DIDN’T have varying degrees of acid damage.

[tjs72lemans]

Yes, having multiple classics to drive as well as a Harley I love to ride limits my cars yearly mileage. Plus the MN area!