Why do some cars burn one oil brand but not another?

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Have driven Hondas for almost 40 years, been keeping records since 2002. Used nothing but Mobil1 in the proper reccomended grade. OCI is approximately 5k on my vehicles, annually on wife's car which is usually less than 5k/yr. Since 2006, always Mobil1 0W-20 AFE/ M1 110/M110A right thru 2019 with Civics and Accords.
Never added a drop between changes. Recently changed to CRV's with the 1.5t engines which seem to be a bit harder on oil than the Civic 1.5t according to the UOA'S performed. Changed to Mobil1 0W-20 EP, same filters, due to somewhat higher OD and subsequent lowered viscosity. I guess future UOA's will tell on those issues and wear metals, but based on past experience, don't expect to see oil usage between changes. The only car I've ever owned that had a usage problem was a 70's VW Rabbit/Golf that had bad valve seals, that was using Castrol GT if I remember correctly.
 
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That is a good question, I never found a real answer to it. In my own VW I use Euro higher HTHS synthetics only, it never used more than 1/2 qt between 3-4K OCI until I used one brand in particular that is supposed to be the best thing since unicorn tears (I wont say but it had HTHS 3.5 and brand name) good god it was drinking it so badly I thought something must be leaking or something like some rings had broken, after 2K into the OCI it was drinking 1qt every 500 miles.

I couldnt find any leaks so I figured I better plan on tearing it down this summer, I changed back to the oil it always used and it stopped, back to what it always was 1/2qt every 3-4K. I have no answer not even a guess.

Edit: The oil was not Mobil or Castrol and cost retail (it is avalable in stores) about $10 a qt
with you Trav, till it happened to me I was very skeptical, but I have sold hundreds and hundreds of gallons and heard many stories
 
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So you're saying that even oils with different manufacturer approvals, certifications and licenses are the same as all the rest?
NOT HYUNDAI, semi-syn as spec'd i even asked about bringing full syn , said not needed, this being said one dealer that offered FREE oil changes
used bulk, and used CORRECT spec for Warranty work, billed back to manufacturer .
 
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I have read this several times here and there. I have a friend who swears his car burned one oil brand, switched to another and hardly any burn. I'm talking same weight.

I switched from M1 to RL and it seems like my car is burning less, but it has only been 600 miles. I want to wait to hit 1000 miles before I draw any conclusions. I did the switch because I thought the burning in my car might be caused by clogged piston rings and RL supposedly cleans better than other oils. I did not want to run an engine flush....have a little bit of a mental block against flushes, but I hear Amsoil's is solvent free and likely is not going to hurt anything.
not hijacking the thread but i had 1 Customer that tracked mileage using different brands, many variables IMHO
 
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NOT HYUNDAI, semi-syn as spec'd i even asked about bringing full syn , said not needed, this being said one dealer that offered FREE oil changes
used bulk, and used CORRECT spec for Warranty work, billed back to manufacturer .
I don’t understand what that means.
 

OVERKILL

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Most people never come to these forums, rarely keep a new vehicle far beyond the factory warranty or yet beyond 10 years and only care about when the OLM tells them to change and where the best price on the next quick oil change. My method is directed at enthusiasts and those wanting to keep their vehicles for long periods of time.
Which is why I specifically mentioned those livelihood applications where the most mileage is accrued.
My wear rates are often 1.5-2x higher when I leave 15-20% of the old in after a spill and fill. I have seen my fuel dilution start off at 1-2% when I do not flush the old oil out and at levels above 4% I see a similar increase in wear. I have seen my iron wear levels start off at 5ppm rather then 0 ppm when I leave the old oil in. That residual wear metals do have an affect on future wear. The viscosity thins out much quicker, and TBN is reduced much quicker when I leave the old oil in.
I think you are conflating wear-rate with residuals from the previous fill. Of course if you don't get all the old oil out those numbers are not going to start at zero. The fact you can measure them however means that all of that is in suspension.
My wife and I follow different oil change methods. She changes every 3k miles in all her cars, with the current recommended API oil that is available at the most convenient oil change service center.. Her car is mechanically sound with no oil consumption, and no fuel dilution, mixed driving and 180k miles. Her camshaft cover and valve train has heavy varnish and deposits. I run 2-3x longer drain intervals, with high fuel dilution and premium synthetic oil and Full Volume oil changes and my valve train has zero varnish and sludge and looks like new at 150k.
I'd suggest cruising through some of the pics that have been posted on here over the years.

This was the S62 in my E39 M5. It has what we would all consider an extremely complex oil system. Dealer oil prior to my acquisition, this run was on M1 0w-40:
M5driveway02.jpg

OCI length I ran was 10-12,000Km (6,200-7,500 miles). This picture was at ~100,000 miles.

This engine fuel diluted like mad, being high performance. As you can see, that didn't result in varnish formation.
How does one know when when the dispersant and detergents holding capacity or threshold is reached. I rarely see much of change in additive levels even when I triple my OCI. Oxidation and nitration only increases small amounts. The dispersants do not help with fuel dilution or wear metals such as iron, aluminum, lead, tin and other metals correct. I think they have some affect on free copper from coolers based what I have read.
It should track with the depletion of the TBN in the oil for the most part. The compounds used to neutralize acids are the same ones used to keep contaminants in suspension. And yes, these help with the wear metals (that's why you can measure them in your UOA) while fuel is just a diluting agent (thinning primarily, though it does work to degrade the oil as well).

Some polar bases, like esters, will chelate copper from oil coolers, I think that's what you are thinking of there.
I would like to see some actual comparative studies between short volume oil changes vs full volume oil changes with respect to wear rates, and lube performance with both normal and extended drain intervals. Many interested parties would cry at the thought of the so-called wasted oil with FVOCs.
@Doug Hillary did extensive fleet tear-down testing of some 500HP Detroit Diesel engines run on Mobil Delvac 1 5w-40 in the Australian outback. OCI's were around 100,000Km, he used centrifuges to control soot loading. There were pictures posted on here from a 1.2 million km tear-down (~750,000 miles) where the liner and bearings measured "as new" and were returned to service.

As I noted previously, the highest mileage vehicles are typically OTR trucks for diesels and courier/taxi/limo service for gas engines. The million mile Ford van was I believe a courier.

The problem with what you are requesting is that nobody operating these fleets of vehicles in service conducive to accruing that type of mileage is going to intentionally waste oil for the purpose of this experiment unless somebody else was footing the bill. If a taxi fleet is able to get 500,000 miles out of a Modular before the valve seals are shot and it starts fogging blue, there's little incentive to double their lubricant use just in order to reach that same milestone.

I'd also expect that if there were merit to this approach you would have seen the oil companies pitching it (double consumer oil use?! sounds like a profit windfall!) but they don't. In fact the focus more recently has been on more expensive oils able to be run longer (M1 AP and EP for example) and testing of this duty cycle (Mobil's taxi test).
Wynns Corporation that makes coolant and transmission fluid exchange machines and used by GM dealers also made an engine flush machines that uses clean oil . I have seen these services in Japan and Korea when I lived there.
And Japan is also the place where engines are retired early and sent over here (JDM import engines, in varying condition). I'm not sure that's a great benchmark, referencing a market where achieving high mileage is almost unheard of 🤷‍♂️ And yes, it doesn't surprise me that a company that makes flush machines would make a flush machine targeted at oil as well.
It never took off or was adopted in the US, because so many believe all the oil drains into the pan upon shutdown, and the minute amount still in the engine has no affect on the new oil or engine. My first engine I rebuilt was a Ford 289, much different design and a lot of oil would drain. These new engines with VVT, DOHC designs, turbos, coolers retain far more. I have looked and have not seen any comparative studies, but I do agree with Machinery Lubrication articles on residual oil and short volume oil changes, and their affects, as I have seen similar affects in my own vehicles.
Lots of experience with Windsors here as well, though primarily 302's (currently have a GT-40 351W in a '95 Supra Comp TS6M). The EFI 302's were quite prone to having the PCV screen plug-up, resulting in a loss of crankcase breathing, often leading to significant accumulation of deposits in the valley, even if run on quality oil. I had a high mileage 302HO from my '87 GT that was pristine at ~340,000Km (~210,000 miles):
rockers.jpg

This was another 302HO, we picked it up as a low mileage donor for a car my buddy bought, not high mileage (probably around 60,000 miles?) but M1 0w-40 was keeping it clean. 1st car we put it in (carb, Vic Jr.):
nateengine01.jpg

Same engine, 2nd car, a couple years later:
NateStang302120K.jpg


Then there was this fun 302HO swap into a clearly abused '90 F-150:
Old engine, obviously not well maintained:
f150swap01.jpg

f150swap02.jpg

Donor Mustang engine, had ~150,000Km on it (100,000 miles) IIRC? Run on AMSOIL:
f150swap05.jpg

f150swap06.jpg


We can probably agree that keeping the oil clean and for longer periods, improves performance, improves oil performance, reduces wear and extends the life of the equipment. I do full volume fluid changes on my transmissions and they have all lasted 250k miles or more.
Sure, a high quality oil changed at reasonable intervals using an efficient filter is my go-to, and has worked for me. That said, I've seen enough pictures on here of engines owned and operated by people that don't go to the same lengths but still stay clean that I'm hesitant to paint with too broad a brush. Duty cycle is clearly a huge contributor, as is engine design. The Honda VCM V6, pictures of which @Trav has posted, is an engine that will readily produce copious amounts of build-up when maintained "normally". A Modular in the same service would stay clean. This is just due to the design.
 
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if i remember correctly, noack increases with decreasing viscosity. simply the oil bases are more volatile.

I am running 0w20 and I don’t burn a drop of oil.
since you mentioned drops- discussion should be opened, how precise is the amount of new oil poured and old drained.
(because 1 drop= 50µL)
are the measurements at least this much precise? ;) (calibrated, nice to have)
93_500_odmerny-valec-250-ml-s-certifikatom-o-overeni.jpg
 
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I have read this several times here and there. I have a friend who swears his car burned one oil brand, switched to another and hardly any burn. I'm talking same weight.

I switched from M1 to RL and it seems like my car is burning less, but it has only been 600 miles. I want to wait to hit 1000 miles before I draw any conclusions. I did the switch because I thought the burning in my car might be caused by clogged piston rings and RL supposedly cleans better than other oils. I did not want to run an engine flush....have a little bit of a mental block against flushes, but I hear Amsoil's is solvent free and likely is not going to hurt anything.
Watch the Project Farm YouTube video of him testing many many different oils from the same weight. He put the oil in a coffee pot on a hot plate portable stove, at a steady temp for a certain period of time. He would even rotate the coffee pots to make sure no hot spots. He would weigh the oils before and after. Some oils burned off more than others.
My wife’s old van has burned less oil with NAPA (Valvoline) than it does with Motorcraft. I don’t know why, both oils are great.
 

OVERKILL

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Watch the Project Farm YouTube video of him testing many many different oils from the same weight. He put the oil in a coffee pot on a hot plate portable stove, at a steady temp for a certain period of time. He would even rotate the coffee pots to make sure no hot spots. He would weigh the oils before and after. Some oils burned off more than others.
My wife’s old van has burned less oil with NAPA (Valvoline) than it does with Motorcraft. I don’t know why, both oils are great.

Project Farm is for entertainment purposes only.

There is actually a volatility test run on motor oils (Noack) but that doesn't necessarily correlate with consumption. One of the purposes of capping volatility is to ensure that the presence of lighter fractions is limited enough that it doesn't result in premature oxidative thickening and lead to breakdown and deposit formation, which is important to oils that see extended use. Euro extended drain oils have had Noack capped at 10% for ages, whilst the API limit was 15%.

The oil our Expedition consumed, AMSOIL AZO 0w-30, had extremely low Noack volatility, while the oils it didn't consume, in the same grade, like M1 AFE 0w-30 and Motul 0w-30, had higher volatility figures, though still well below the API limit.
 

4WD

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Project Farm is for entertainment purposes only.

There is actually a volatility test run on motor oils (Noack) but that doesn't necessarily correlate with consumption. One of the purposes of capping volatility is to ensure that the presence of lighter fractions is limited enough that it doesn't result in premature oxidative thickening and lead to breakdown and deposit formation, which is important to oils that see extended use. Euro extended drain oils have had Noack capped at 10% for ages, whilst the API limit was 15%.

The oil our Expedition consumed, AMSOIL AZO 0w-30, had extremely low Noack volatility, while the oils it didn't consume, in the same grade, like M1 AFE 0w-30 and Motul 0w-30, had higher volatility figures, though still well below the API limit.
If PF would stay off of high tech things like lubricants ? - PF is pretty good for say - testing glue …
Stick the same material together with a half dozen competing products … add weights to failure 😷
 

BlueOvalFitter

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My son and I used some Amsoil SS 5W30 in our engines (mine 4.2 V6) (his 5.4 3V) and they both started consuming the oil. We switched back to Havoline Pro-DS 5W30 in both engines with no more oil consumption. 🤷‍♂️
 
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Guess I'm rare then, I have a 22 year-old Sienna with nearly 450,000 miles on it, a 21 year-old ECHO with almost 300,000 and a 25 year-old Accord that just turned over 300,000 this weekend. Up until recently I had a 27 year-old BMW with about 260,000 miles.

I don't do any of that flushing routine and generally do 10,000 mile OCIs in the ECHO with less in the Accord and Sienna. I've posted pictures here of the valve train, none have a lot of varnish and none have any sludge. In fact the ECHO looked fantastic when I replaced the valve cover gasket (for the first time) about 10,000 miles ago. From what I see it has a lot more to do with the specific engine and operating conditions rather than the oil.

How are you measuring relative wear rates? Surely not via UOA.
What kind of oil are you using?
 

TiGeo

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For the cars in my signature, I have no dicernable oil consumption.

For the Sportwagen, I have tried several different VW502 00 oils (LM LLHT 5W40, LM Molygen 5W40, M1 5W40, M1 0W40, QSUD 5W40) in the last year and none of them show any consumption.

For the Focus, it went from dealer MC syn blend 5W20 changes for it's whole life since new with no consumption to ST HM 5W20 syn this past change; no consumption noted.

For the Lexus, it went from dealer changes (not sure what Toyota/Lexus dealer oil was used or if there was any consumption..it was my parent's) for it's whole life to ST HM 5W30 syn this past change; no consumption noted. This vehicle had the oil cooler line blow while my son was driving it and it was driven with v. little oil left in it before he cut it off.

The W8 hasn't shown any consumption since owning this year on LM LLHT 5W40 and some additives.

The Atlas has had numerous dealer oil changes and has had both 502 and 504 varieties (Castrol and Mobil). I have noticed some consumption but it has varied. Currently using LM LLHT 5W40 and not showing any consumption this fill.

My take away is using oils with the same approval/specs and viscosity will yield similar results.

The only car I've owned that had some consumption issues was my wife's MK4 Jetta ('00) w/2.0. When new, it had some notable consumption (shocking actually) but after taking over DIY changes and using M1 0W40, it drastically was reduced. If I recall, the dealer/other were using 5W30/who knows approvals. That car was known to have consumption issues that were related (from what I remember) to incorrectly installed piston rings at the factory. Regardless, 0W40 sorted it and I sold it after 14 years and 220K. Car went to 300K with second owner.
 
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I have an old car I drive on weekends. A little high revving stroker if you must know. I always use the exact same oil and OCI and filters, yet sometimes it burns a few ounces of oil between oil changes and other times it does not seem to burn any at all.
 
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