NEw oil= increased engine wear?

[ziggy]

I had recently read, that when you drain old oil, and add new oil you are actually causing increased enigne wear, that the new oil needs to be broken in ect, and wont have the same lubricity of hte old oil thats colected dirt and mileage. Is this true? I find that hard to belive... I alwasy thought changing your oil, every 3 months/3,000 miles, whichever comes first,w as the ideal thing to do? As you would be draining out any built up contaminants, replenishing the additive pack with new oil ect/

 

[Ugly3]

There are several studies that suggest used oil produces lower wear rates than new oil. One of the pieces of data I found interesting was the 3MP synthetic oil life study. There was lots of conversation here on BITOG on the subject.

This is one of the small reasons I run 10,000 mile OCIs with synthetic, the biggest reason is I am too old and fat to change the oil.

 

[mechtech2]

In general, it's a safe bet that new clean oil with a lot of fresh additives is better than sheared down, depleted, contaminated oil.

 

[Rickey]

Some have speculated that the fresh oil cleans up contamination left unremoved by the old oil. Sounds hard to prove, and it is an interesting hypothesis.
Rickey.

 

[Ugly3]

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Some have speculated that the fresh oil cleans up contamination left unremoved by the old oil. Sounds hard to prove, and it is an interesting hypothesis.
Rickey.

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Pretty much disproven in the 3MP study where he did a "flush" before each run.

 

[Ugly3]

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In general, it's a safe bet that new clean oil with a lot of fresh additives is better than sheared down, depleted, contaminated oil.

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How about fresh oil verses used oil with 3,000 highway miles on it? The data suggests that the 3,000 mile oil will produce less ware.

 

[Cujet]

Well, there certainly is anecdotal evidence to the contrary. In fact, those who regularly change oil are nearly guaranteed to have longer engine life. All those worn out car engines cannot be wrong. Just where the tipping point is, is the question.

Chris

 

[Ugly3]

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Well, there certainly is anecdotal evidence to the contrary. In fact, those who regularly change oil are nearly guaranteed to have longer engine life. All those worn out car engines cannot be wrong. Just where the tipping point is, is the question.

Chris

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Look at what some the car makers are recommending now. Honda is at something like 10,000 mile OCIs and others have raised their OCIs too.

 

[Pablo]

Most inorganic boundary protectants in motor oils are heat/pressure activated. Fresh oil that just begins to circulate is not fully "active". This is a nearly perfect world view - if you throw in real world stuff - like some engines retain a quart of old oil, this effect gets fuzzy.

I certainly wouldn't sweat it.

Keeping it simple - this is why sometimes a motor oil is not necessarily the best choice in all gear boxes.

 

[CBDFrontier06]

Sounds like there's a HUGE hole in the lubrication market for used oil. They should bottle and sell it with an anti-wear guarantee.

 

[JAG]

SWRI did a great test on this using radioactive tracers (not UOAs) showing it's true. There is a tipping point though which of course depends on a bunch of factors. Trashed oil is still bad.

 

[Laminar Lou]

I paid for the SAE paper on using the radioactive tracer on cam lobes and read it (2003-01-3119). They basically found that there was a scavenging effect on the anti wear film of the previous oil when a fresh oil is introduced. I'd quote the paper but that would be copyright infringement. But they definitely concluded that used oil produced lower wear rates then fresh oil on a broken in surface and even on a new surface.

I've seen evidence in too many places that show that changing your oil more often than is needed will cause more wear. Note I say more often then needed. So people who are changing oil every 3K when they have an OLM that says they only need to change it every 10K or 15K think they are "better than the engineers" are causing needless wear on their engine and wasting money.

Now whether the "extra" wear from changing you oil more often then necessary will actually result in premature engine failure remains to be seen. But it seems senseless to me to ignore the OLM or manufacturers guidelines because Jiffy Lube, your Dad, or some mechanic tells you to.

 

[JAG]

Good post LL. I didn't know it was due to new oil scavenging the previously set up anti-wear film but that makes sense. That raises another question. Is the film being scavenged because of a cleaning effect or because the anti-wear additives in the new oil haven't been activated, thus not being able to keep the film from wearing away in the early stages?

 

[PT1]

With the new OLM systems out even the severe service I run with short trips all the time I still get at least 4000 miles on the OLM in worst case scenario. So there goes the 3000 mile oil change theory.That said, I wouldn't want to take a Toyota past 5000 oci because of the fear of it becoming a sludge factory. I have seen 3 friends all with different Toyotas have sludge issues.

 

[hominid7]

I've always been one to over-maintain my cars and actually have to make an effort not to change the oil too often. All of my previous cars have 'suffered' the same treatment of too frequent oil changes.

The car i owned the longest, a VW Jetta i owned for 10 years might have made it to 3,000 miles between oil changes a couple of times, but usually it was changed monthly at around 2000 miles. It never complained, and was spotless inside and out when i sold it with well over 200,000 miles on it.

The oil filter on that thing was pretty huge and must have held 3/4 of a quart of oil. I never (i repeat never) pre-filled any filter, i just let the engine clack for 5 to 10 seconds upon start-up after changing the oil until the ultra thick Napa-Branded Valvoline 20w50 i used year-round for it's whole life managed to pump its way around.

So to answer your question, does fresh oil cause more wear? I dont know. However it does not seem to produce enough in my experience to warrant extended oil change intervals specifically to avoid any 'harm' done by fresh oil or dry start-ups caused by a new oil filter.

I've been doing better on my current car by letting it go to 3,000 between changes. I even went 3,500 miles once! Of course there was also that time i changed the oil 3 times in one week while experimenting with different brands and viscosities.

A week of vacation can be a dangerous thing.

 

[Laminar Lou]

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Good post LL. I didn't know it was due to new oil scavenging the previously set up anti-wear film but that makes sense. That raises another question. Is the film being scavenged because of a cleaning effect or because the anti-wear additives in the new oil haven't been activated, thus not being able to keep the film from wearing away in the early stages?

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That is the million dollar question I think. I briefly skimmed the article again (it's good reading actually if you want to spend the $20 at SAE.org). The paper did say that "new compounds" in the old oil may provide wear protection. I would draw the same conclusion myself since they cleaned the cam lobes in part of the test with mineral spirits to remove the antiwear film and when they introduced used oil back into the test the wear rate was high initially (like the fresh oil) but dropped to a much lower wear value compared to the new oil. If you looked at the charts on the paper, it was a very significant amount.

So really there are 2 reasons for increased wear. One is the scavenging effect of new oil removing and replacing the antiwear film and the other is that the new oil hasn't created the "new compounds" (or activated the chemistry as you stated) yet.

They did compare the 3 on one graph:

1) fresh oil on fresh surface
2) old oil on fresh surface
3) old oil on broken in surface

The wear rates were ranked in that order with #2 leveling off after 10 hours and hugging the same near horizonal line as #3 (but significantly higher).

I have seen similar information here at BITOG with UOAs and at the famous Mobil1 test on extended drains here (who cited the same SAE study by the way): synthetic oil life study

 

[Sparkman]

I don't have any technical knowledge in this area, but I will offer one tidbit for thought.

Perhaps the worst oil starvation my well-cared-for engines ever see is immediately following an oil change. The engine experiences a prolonged period of low oil pressure after having the oil drained and a new filter installed, as compared to a normal start. I dare say that this does actually generate some extra wear compared to a normal start, though I don't dare speculate to its relative severity.

 

[cmhj]

Might be another good reason to not worry about getting out that "very last drop" when doing OCs unless it's way overdue.

I know I don't get too fussy. Drop the plug for 2-3 min. and go from there. However, I do dump my oil filter if re-using it.

 

[cmhj]

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Might be another good reason to not worry about getting out that "very last drop" when doing OCs unless it's way overdue.

I know I don't get too fussy. Drop the plug for 2-3 min. and go from there. However, I do dump my oil filter if re-using it.

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This could also be another arguement against those that can't see the benefit of using syn type oils, which then allows extending OCIs.

 

[Ugly3]

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I paid for the SAE paper on using the radioactive tracer on cam lobes and read it (2003-01-3119). They basically found that there was a scavenging effect on the anti wear film of the previous oil when a fresh oil is introduced. I'd quote the paper but that would be copyright infringement. But they definitely concluded that used oil produced lower wear rates then fresh oil on a broken in surface and even on a new surface.

I've seen evidence in too many places that show that changing your oil more often than is needed will cause more wear. Note I say more often then needed. So people who are changing oil every 3K when they have an OLM that says they only need to change it every 10K or 15K think they are "better than the engineers" are causing needless wear on their engine and wasting money.

Now whether the "extra" wear from changing you oil more often then necessary will actually result in premature engine failure remains to be seen. But it seems senseless to me to ignore the OLM or manufacturers guidelines because Jiffy Lube, your Dad, or some mechanic tells you to.

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Great post!