Old Oil - really, really old oil...

[patrickt]

As most here know, I tend to change my oil every three or four years and instead rely on oil analyses from oil sucked out of the pan through the dipstick every 500 miles or so. I spend more money on lab reports than most of you spend on oil changes. But those lab reports consistently tell me that there is no reason to change the oil and, more importantly, act to red-flag any unusual conditions that might be going on inside my solid flat tappet FE engine before they become really bad news. So, I wondered... could I go five, ten, fifteen years this way? 25? How about 50? If you look on the internet there are a ton of non-scientific articles that claim that "oil deteriorates over time so you need to change it based on age as well as mileage." Most seem to use almost the exact same language, like they copied it off the guy before them. But the oil lab people are quite adamant that they simply don't see time as a factor. So I asked, "do you ever test old oil just to see if it's gone bad?" And the answer was "of course we do." And the question, does oil age differently if it's in my pan as opposed to a can on my shelf? Here is the fascinating, and fun, reading on when they analyzed the ebay oils that are now decades old.

https://www.blackstone-labs.com/wp-c...ils-Part-1.pdf
https://www.blackstone-labs.com/wp-c...ils-Part-2.pdf
https://www.blackstone-labs.com/wp-c...ils-Part-3.pdf


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[twobjshelbys]

Originally Posted by patrickt

... "oil deteriorates over time so you need to change it based on age as well as mileage."

Bull puckey. Have you ever seen a wildcatter punch a hole in the ground, hit oil, and then cap it because it "was too old"?

Do you see expiration dates on the cans in the store?

[SOKRATES]

Interesting. just curious, where or which lab does the analysis for you? what constituents do you measure?

[Unique427]

Originally Posted by twobjshelbys

Bull puckey. Have you ever seen a wildcatter punch a hole in the ground, hit oil, and then cap it because it "was too old"?

Do you see expiration dates on the cans in the store?

Ya, and did the oil coming up out of the ground
already have a refined additives package and
viscosity indexers premixed in it?

Shelf life of a properly stored unopen container is generally accepted at (5) years (according to Mobil1).
The main issue is separation of components.
The additives can settle into a goop on the bottom.

Engines are expensive.
Fresh clean oil is cheap insurance and peace of mind.

[patrickt]

Originally Posted by SOKRATES

Interesting. just curious, where or which lab does the analysis for you? what constituents do you measure?

I use Blackstone Labs, and have for decades. Not because they're the best, just because they're who I use. Their results check for and measure the presence of wear metals, the levels of additives, the presence of insolubles, water, antifreeze, they measure the viscosity and flashpoint and give you a total TBN number. Just like your blood work at your yearly physical, the numbers are important, but the trend is absolutely fascinating. If you watch it carefully, it will tell you volumes. Much more than if you just blindly change your oil every six months (like some around here recommend, mostly for "peace of mind"). Kind of like the doctor saying, "I know you say you feel great, but your numbers are all down and show you're anemic and your white cells are off the charts. Let's do a little follow-up." Now, the flip side of that is "ok, so what if I just never bother checking wear metals, or for the presence of antifreeze, and one day I eat a cam lobe?" I just pull the engine, put it in a crate, send it to blykins along with a fat check and say "fix it." This is not life and death; it's just a stupid hobby.

Originally Posted by Unique427

The main issue is separation of components.
The additives can settle into a goop on the bottom.

Ahh, you did not read the articles - shame on you (you would then be roasted in front of the class for the next hour). They controlled for that by comparing 50 year old oil that they had put in a paint shaking machine versus cans from the same case that were tested untouched. But that's ok, you're buying peace of mind.

Originally Posted by Unique427

Shelf life of a properly stored unopen container is generally accepted at (5) years (according to Mobil1).

And if I was writing the warranty/rep language I would cap it at five years too. Even if the engineers said "Pat, I think this stuff will last a hundred years and still be good as new." Remember, the people in the oil labs say they don't see time as a factor. But if I'm defending some sort of really expensive claim for the oil company and I find out the guys on the other side used ten year old oil do you think I'm going to proffer scientific evidence? Of course not. I'm going to say "look, it clearly says this oil is no good after five years, can't you morons read?"

[eschaider]

In the FWIW bucket, I decided to experiment with oil changes on a new car I bought in 1977. I drove a lot more back then than I do now so oil changes were a regular occurrence and reprensented something I wanted to minimize.

I did some quick math and determined oil changes and engine rebuilds were in the same ball park for daily driver types like me. I decided to not change oil and just top it off from time to time as needed and see what happened. I drove that car 398,000 miles and never changed the oil or the engine.

On two occasions I had to replace the oil filter because it rusted out (New England winters and road prep). Never smoked and only used a quart of oil every two or three months. The engine was a 385 series 429.

Today's engines are likely more tender and may require more attention to oil changes. All that said Patrick is right about oil and aging. Blackstone Labs will give you more knowledge about what is happening inside your engine than a trip to the parts store for oil.


Ed

[1795]

Originally Posted by twobjshelbys

Bull puckey. Have you ever seen a wildcatter punch a hole in the ground, hit oil, and then cap it because it "was too old"?

Tony,

Isn't oil by definition very old, around 50-250 million years old?

What's the difference of a few more years......

Take care, hope that you are having nice weather.

Jim

[1ntCobra]

Hmm, I used to be under the impression that you drove your Cobra more often than RodKnock, now I am not so sure.

[twobjshelbys]

Originally Posted by 1795

Tony,

Isn't oil by definition very old, around 50-250 million years old?

What's the difference of a few more years......

Take care, hope that you are having nice weather.

Jim

Yep. The other way is I don't see oil wells with a sign that says "too new, must age another 2m years".

Been summery for a week or so. Almost 100. Huge winds came through with a cold front and won't break 70 today. Pool was over 90. Cover blew off so low 80s today.

[patrickt]

Originally Posted by 1ntCobra

Hmm, I used to be under the impression that you drove your Cobra more often than RodKnock, now I am not so sure.

As I've gotten older, I do tend to drive it less. Which brings about an interesting point, what crucial fact does a detailed oil sample not tell me? Everyone by now knows that if you have a solid flat tappet you have to be mindful of ZDDP levels in the oil. And how much ZDDP do you need? Answer: Enough. And it gets consumed as you encounter metal to metal contact. But that metal to metal contact just eats up your ZDDP, not your Zinc and Phosphorus numbers. So when I see an oil analysis that tells me that my used oil still has some really healthy numbers of Zinc and Phosphorus in it I still don't really know what my ZDDP numbers are now. I just know what they were when the oil was new. Kind of like if I split water in to hydrogen and oxygen. I'll still have the same amount of H and O2 that I did before, but I won't be able to drink it if I'm thirsty. And that's why with a SFT in your car you do need to watch the mileage in addition to the lab results. Or you can just wait until you see the wear metals start to go up and then say "ok, I should have changed the oil last time I had it tested."

[hauss]

you did not mention detergents or anti foam all important additives that get consumed . that"s why I 15/40 Cheveron Delo in the 427 stroker every 2000 or 6 months. By the way 8k and counting.

[patrickt]

Originally Posted by hauss

you did not mention detergents or anti foam all important additives that get consumed .

That's the TBN (total base number). Easy to compare and see how the detergents are being consumed. But that brings up another topic. Did you know that changing your oil too often will actually increase the wear on your engine? Tribochemistry. The interaction between the anti-wear additives and detergents creates an upswing in initial wear. You'll win a few barroom bets on that one.

[NROTOXIN]

Originally Posted by patrickt

That's the TBN (total base number). Easy to compare and see how the detergents are being consumed. But that brings up another topic. Did you know that changing your oil too often will actually increase the wear on your engine? Tribochemistry. The interaction between the anti-wear additives and detergents creates an upswing in initial wear. You'll win a few barroom bets on that one.

Is that engine oil's equivalent of GOOD FLORA vs.BAD FLORA?

[patrickt]

Originally Posted by NROTOXIN

Is that engine oil's equivalent of GOOD FLORA vs.BAD FLORA?

Kinda. More like all things in moderation. Including oil changes, detergent additives, and anti-wear agents.

[saki302]

Years ago, my best friend said (regarding really low mileage cars) what difference does it make if the oil sits in a pan or in a bottle on the shelf? ��

I have an ancient honda Z50 which probably has some (good) 30w oil in it that's 2 decades old.. it hasn't blown up yet, but I don't ride it much.. i should probably change it ��
It also runs well on old gas.. but the 8 month old gas in there now is relatively fresh bu comparison (sta bil ized).

[Hotoxide]

I'm surprised no one has mentioned synthetic oil.

Dave and SNAKE65 - on a slippery slope

[patrickt]

Originally Posted by Hotoxide

I'm surprised no one has mentioned synthetic oil.

Dave and SNAKE65 - on a slippery slope

I've used BradPenn 15w-40 forever. Back when I was a kid, it was called Kendall oil and it was green. We always thought it was good stuff. Somewhere around twenty years ago the name Kendall got sold, so it went one way and the green oil went another and became BradPenn. Today's Kendall bears no resemblance to the old Kendall oil at all. Today's BradPenn, which is still green, is also "partially synthetic." Maybe it was always partially synthetic. I don't know exactly what that means. They could just as easily call it "partially natural" or "semi-organic" I suppose. I don't know if the green color comes from dye or not, but I've always kind of liked that. I don't know if the Kendall from when I was a kid was partially synthetic, partially natural, semi-organic or what. But it was green, it seemed to work, and we were kids and knew everything there was to know under the sun. We knew it all. All I know now is what I read on the 'net, and 99% of that is total and complete BS.

[patrickt]

... and I can't remember whether we followed this oil change advice.

[DanEC]

I followed it up until about the late 70s when I realized at least one good thing about unleaded was the plugs and oil seemed to stay clean longer so I figured I could start stretching out those 2000 mile intervals longer.

[MD427]

This is interesting stuff regarding oil age. And it makes enough sense. Not sure if that means I'm willing to forgo an annual oil change...

On the other side of the coin, I recall a fairly recent article. A big name mfg, (want to say, Volvo?) basically put forth the idea that oil doesn't really go bad by itself, it is the accumulated broken down components of everything else that ruins oil over time/mileage. Metals, moisture, fuel blow-by, dirt, pollen, etc. act as contaminants.

I suppose to validate this they designed some super-duper oil filtration system. Then filled up one of their semi trucks and ran it for a million miles. At normal oil change intervals the old oil was run through said super filters and replaced into the semi.

I do think the jist of it was just what was stated, with sufficient filtration, the oil performance never degraded appreciably over the test. After being "properly" filtered of contaminants the used oil performed as well as new.

So I guess if you had a good enough oil filter system you could run the same oil "forever" just replacing the bit consumed over time by combustion and unrecoverable from your filters.

But again, I'm not going to volunteer to be first in line for that experiment.

Edit: After posting I decided to go look it up because I don't want to be the source of a mis-truth on the internet.... I can't find any 1 article referencing Volvo conducting this experiment. What I can find is a 'test' sponsored by "Safety-Kleen" (a producer/seller of "re-refined" engine oil) did a comparison between a truck running its recycled oil vs one running virgin oil. And separately I see some trucking fleets have installed a system that filters oil at 1 micron and burn/scavenges the waste, and at least 1 company running that system is claiming t get nearly 200,000 miles between changes.
So, objectivity aside both cases do seem to support the notion that 'clean' oil is more important than 'new' oil.