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

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in that case level may stay or rise, due to fuel dilution. diesels are most prone.
does the oil pass sniff test?

even if the engine does not consume a drop, oils are commonly at ~10% noack.
that´s probably why i see miniscule decrease on dipstick of a thick 3,9 hths 5w40 (long ~1h trips, no gasoline smell)
No fuel in the oil that I can smell.

I'm sure the engine is not perfect and uses some oil (in an amount that is negligible). All the vehicles I have now get their oil checked monthly just as a precaution.

Those two Chryslers I owned needed top-up every 2-3 weeks. It was significant. I even waited until the oil hit the low mark on the dipstick to see if oil level had any impact on the consumption rate. Nope. They drank it at a constant rate. At oil change time, I would buy 1 filter and 2 jugs of oil. One jug to pour in and the other to top off with. When the second jug was empty and the engine needed topping off, the van would have about 5000 miles on it.
 
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How many quarts of oil does your engine hold? Do you drain 3 quarts, top it up with the new oil you plan on running, run the engine 20 minutes, drain that, then swap the filter and fill with the oil you plan on using?
I complete a normal filter change, long drain, then refill with 3 quarts in the 5qt system. If I use a less expensive petroleum flush oil, or drive on the highway, I put the whole 5 quarts in. Then run for 20 minutes to operating temp. You can run a lower capacity sump if your just idling. The second drain will come out dark as the new and old oil mixes. This is far safer and more effective than using harsh solvent flushes, and the percentage of solvents do not circulate with the old oil for the next full OCI. The new oil does not need to use its additive package to counter the oxidation and contaminants of the old oil. I have a by-pass filter, and this time I will experiment with a Drain & Refill and a line purge that some in the machine industry use. My by-pass filter is after the full flow filter and at the end of the circuit before oil returns to the sump so it will not starve other parts of the engine. Figure I can use half as much flush oil as the double oil change. I reuse my flush oil in an older car, use it a second time as a flush, or used in my yard equipment.
 
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That "fella" MACTFORDEDGE knows little about what he's claiming to know. I've watched his videos before (as they have been referenced on here multiple times) and he's seriously lacking in technical knowledge and basic experimental procedures.
Believe me I know, been kicked off his FB page for suggesting logic and the scientific method. He turns off all commenting on his videos because he does not have time to respond to them all. LOL, Of the videos I have watched, this was the only one I found of marginal value, but common sense will tell you that additives, VIIs, various base oils and binding agents were not going to play well together, regardless of driving conditions.
 
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I complete a normal filter change, long drain, then refill with 3 quarts in the 5qt system. If I use a less expensive petroleum flush oil, or drive on the highway, I put the whole 5 quarts in. Then run for 20 minutes to operating temp. You can run a lower capacity sump if your just idling. The second drain will come out dark as the new and old oil mixes. This is far safer and more effective than using harsh solvent flushes, and the percentage of solvents do not circulate with the old oil for the next full OCI. The new oil does not need to use its additive package to counter the oxidation and contaminants of the old oil. I have a by-pass filter, and this time I will experiment with a Drain & Refill and a line purge that some in the machine industry use. My by-pass filter is after the full flow filter and at the end of the circuit before oil returns to the sump so it will not starve other parts of the engine. Figure I can use half as much flush oil as the double oil change. I reuse my flush oil in an older car, use it a second time as a flush, or used in my yard equipment.
Interesting, you have no concerns idling for 20 minutes with being down 2 quarts of oil? I realize it's not under load, I'm just curious, that's all. Thanks.
 
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It’s the same way with heavy duty trucks I found. My Series 60 used Rotella but hasn’t required any make up of the Detroit branded 15w40(Delvac). Oil pressure is also up slightly with Donaldson filters over the Wix I had on it.
 
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Interesting, you have no concerns idling for 20 minutes with being down 2 quarts of oil? I realize it's not under load, I'm just curious, that's all. Thanks.
The engine retains 3/4 to a full quart of old oil in the pump main and two minor oil galleries, in the VVT, on top of the cylinder head and many bearings and small oil orifices. Not worried about it, as the flow rate is rather low at 900 rpm. Requirements would vary based on engine and design. I have done it both ways and monitored oil pressure and oil analysis immediately afterwards show no wear materials. The oil remains very clean for several thousand miles, compared with a normal spill and fill.
 
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The engine retains 3/4 to a full quart of old oil in the pump main and two minor oil galleries, in the VVT, on top of the cylinder head and many bearings and small oil orifices. Not worried about it, as the flow rate is rather low at 900 rpm. Requirements would vary based on engine and design. I have done it both ways and monitored oil pressure and oil analysis immediately afterwards show no wear materials. The oil remains very clean for several thousand miles, compared with a normal spill and fill.
Why not just spill & fill twice as often? You'd use the same amount of oil.
 
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The engine retains 3/4 to a full quart of old oil in the pump main and two minor oil galleries, in the VVT, on top of the cylinder head and many bearings and small oil orifices. Not worried about it, as the flow rate is rather low at 900 rpm. Requirements would vary based on engine and design. I have done it both ways and monitored oil pressure and oil analysis immediately afterwards show no wear materials. The oil remains very clean for several thousand miles, compared with a normal spill and fill.
Thanks. It sounds like you did the homework for your application. I'd feel more comfortable being a quart low on the dipstick, but that's just me. Depending on the engine itself there are some safety margins built into how low the oil level can be before there's a cause for concern.
 
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Why not just spill & fill twice as often? You'd use the same amount of oil.
So I can run premium oil, 100% synthetic oil 2-3x longer as opposed to using less expensive oil, and not have to deal with the residual wear metals, fuel dilution, soot and contaminants, and oxidized oil for another full OCI or more. In my engine, 15% of the oil would run another full 4k OCI, for a total 8k, and 2-3% of that would see three OCIs a total 12k. Every wonder why engines still see heavy varnish build up on static surfaces, even when regular oil is changed more often. The wear metals and fuel dilution also accumulate and not all are drained out, which increases wear rates in the long term. Probably why OEMs say to run a full OCI on new engines, they come from the factory with a full sump of clean oil. I dont though, need to get the break-in metals and contaminants out early. I use the original flush oil in older cars, lawn equipment or second time to reduce waste.
 
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Mind me asking for a car that start burning oil, what care is recommended?
The treatment depends on the source and reason for the oil consumption. If the valve stem seals are hard and leaking, they need to be replaced. If the PCV system is not performing well or partially clogged, then cleaning and repair is needed. If rings are gummed up and stuck, some top end solvents in the cylinder can loosen them up and restore sealing. If the rings and pistons and rings are worn, they need to be replaced. Try a high quality oil with a lower volatility score, and/or high viscosity. I do not recommend oil additives.
 

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Every wonder why engines still see heavy varnish build up on static surfaces, even when regular oil is changed more often. The wear metals and fuel dilution also accumulate and not all are drained out, which increases wear rates in the long term.

They don't. Plenty of engines, even run on cheap bulk oil changed regularly end up looking fantastic at high mileage. We've had plenty of "post under your valve cover" threads here.

Contaminants, such as broken down VII molecules, soot and the like are held in suspension by the detergents and dispersants that make-up the lubricant's additive package. It is when the contaminant holding capacity of that lubricant is exceeded that these products plate-out on surfaces, most often those that are cooler and low flow. As long as the lubricant is changed before this threshold is reached, things will stay clean.

If you have an engine that is extremely hard on oil and rapidly breaks it down, it doesn't matter if you flushed it 5x before an OCI, if you exceed its contaminant holding capacity, deposits will form as a result.

If you have an engine that is extremely easy on oil, as long as the lubricant is changed at a reasonable interval that is below its threshold for contaminant holding capacity, things will remain clean.

Wear is more to do with duty cycle and design, not oil change procedure. That's why OTR diesels rack up obscene mileage and why the highest mileage gas vehicles on the road are typically seen in some sort of courier, limousine or taxi service, none of which experience exotic oil change rituals but all of which have long periods of stead-state operation with oil up to temperature.

Does that mean we shouldn't strive to do what we feel is best for our equipment? Absolutely not, but I think it important to acknowledge that most people will never accrue the type of mileage that vehicles maintained far less rigorously will see in service more conducive to it.
 
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2015 Chevrolet Trax. I have used PP, PPU, QSUD, M1 original, Valve synth, Castrol Edge, Motomaster F1, and Kirkland synth. I don't even go close to GM mileage %. Usually change around 9000kms and the meter is reading 40% left. I'm at 110k kms on the odometer.

Castrol Edge burns or evaporates I dunno it's just goes away. Every other oil is just fine. Castrol just disappears and there is considerable smoke/vapour when I open the oil cap. was topping off well before 5000kms. Every other oil is just fine. It is my personal opinion that Castrol Edge is complete garbage. I'm Using Kirkland now only cause it's the cheapest by far and is working great.
 
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2015 Chevrolet Trax. I have used PP, PPU, QSUD, M1 original, Valve synth, Castrol Edge, Motomaster F1, and Kirkland synth. I don't even go close to GM mileage %. Usually change around 9000kms and the meter is reading 40% left. I'm at 110k kms on the odometer.

Castrol Edge burns or evaporates I dunno it's just goes away. Every other oil is just fine. Castrol just disappears and there is considerable smoke/vapour when I open the oil cap. was topping off well before 5000kms. Every other oil is just fine. It is my personal opinion that Castrol Edge is complete garbage. I'm Using Kirkland now only cause it's the cheapest by far and is working great.
I wonder how Castrol Edge 0W-40 gets all those approvals?
 
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They don't. Plenty of engines, even run on cheap bulk oil changed regularly end up looking fantastic at high mileage. We've had plenty of "post under your valve cover" threads here.

Contaminants, such as broken down VII molecules, soot and the like are held in suspension by the detergents and dispersants that make-up the lubricant's additive package. It is when the contaminant holding capacity of that lubricant is exceeded that these products plate-out on surfaces, most often those that are cooler and low flow. As long as the lubricant is changed before this threshold is reached, things will stay clean.

If you have an engine that is extremely hard on oil and rapidly breaks it down, it doesn't matter if you flushed it 5x before an OCI, if you exceed its contaminant holding capacity, deposits will form as a result.

If you have an engine that is extremely easy on oil, as long as the lubricant is changed at a reasonable interval that is below its threshold for contaminant holding capacity, things will remain clean.

Wear is more to do with duty cycle and design, not oil change procedure. That's why OTR diesels rack up obscene mileage and why the highest mileage gas vehicles on the road are typically seen in some sort of courier, limousine or taxi service, none of which experience exotic oil change rituals but all of which have long periods of stead-state operation with oil up to temperature.

Does that mean we shouldn't strive to do what we feel is best for our equipment? Absolutely not, but I think it important to acknowledge that most people will never accrue the type of mileage that vehicles maintained far less rigorously will see in service more conducive to it.
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.

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.

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 have seen many of the same examples as well on both ends of the spectrum.

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.

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. 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. 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.


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.
 
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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.
 
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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.
How is that possible? The particle size measurable by an ICP is too small to cause wear. We are talking nearly atomic size, more in solution than anything else. Are you performing UOA with an acid digestion?
 
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