Wear Increases After OC?

[CarbonSteel]

It has been said here at various times that increased wear rates happen after an oil change. While I can potentially see that happening if the oil brand/type was changed or if there was a reformulation of the oil currently being used that happened between the oil changes (like changing additive packs or API designation), but with everything else remaining the same, I wonder if wear rates really do increase after an oil change.

Components of the additive pack linger past the OC when the new oil does not have that component (titanium vs. moly or sodium as an example). Ergo, logically thinking why would there not be remnants of higher concentrations of wear metals which are in the oil that remains in the engine after an oil change and it levels off as the new oil picks up new wear metals.

It would also seem the only way to know if my hypothesis has any merit to it would be the completely clean the engine internals between OCs as part of a controlled test (which may not be feasible), but it would eliminate some variables.

Here Mobil Super 5000 has sodium as part of its additive pack, but Kendall does not (as far as I know), yet you see sodium showing in the Kendall UOAs after the MS5K was used. If this is true and it appears to be, what is stopping wear metals from doing the same?

What are your thoughts?

 

[ZeeOSix]

If the new oil strips away a lot of the AF/AW tribofilm that was produced by the previous oil run, then it's possible there might be a slight decrease in wear protection (and more wear) for components in the boundary and mixed lubrication realm until the new oil can build back up the tribofilm.

 

[CarbonSteel]

If the new oil strips away a lot of the AF/AW tribofilm that was produced by the previous oil run, then it's possible there might be a slight decrease in wear protection (and more wear) for components in the boundary and mixed lubrication realm until the new oil can build back up the tribofilm.

I would agree with that, but how do you discount the inevitable residual wear metals? I also not sure how the wear rates are being measured--is it via UOA or a tear-down?

 

[ZeeOSix]

I would agree with that, but how do you discount the inevitable residual wear metals? I also not sure how the wear rates are being measured--is it via UOA or a tear-down?

Residual wear metals?

Best way to measure wear would be with radioactive parts to monitor the real time wear ... but it's probably super expensive testing that only places like the SWRI does.

Radioactive Wear Measurement

We have used radioactive tracer technology (RATT®) for over 50 years to make highly accurate and sensitive, real-time wear measurements in operating engines and other mechanical systems. Friction and wear are typically measured in engines to evaluate lubricant chemistries, component design, and...

www.swri.org

SwRI adds unique, efficient engine wear testing rig

Southwest Research Institute recently added an additional single cam rig (SCR) to its considerable array of tribology testing equipment. The rig, which investigates wear mechanisms in engine valvetrain components, was designed and created by SwRI staff led by Staff Engineer Dr. Peter Lee.

www.swri.org

 

[SC Maintenance]

I would agree with that, but how do you discount the inevitable residual wear metals? I also not sure how the wear rates are being measured--is it via UOA or a tear-down?

I think maybe your referring to this thread?

Another "Taxi" Study: Relationship of Engine Bearing Wear and Oil Rheology 872128

1987-11-01 Relationship of Engine Bearing Wear and Oil Rheology 872128 Member OVERKILL referred to this SAE paper, another Taxi test. It is from a 1987 published paper but I felt it was worth reviewing: One premise they stated was: ...it is not clear that thicker oil films will lead to less...

bobistheoilguy.com

My guess is things have changed a bit since 1987?

 

[CarbonSteel]

Residual wear metals?

Best way to measure wear would be with radioactive parts to monitor the real time wear ... but it's probably super expensive testing that only places like the SWRI does.

Radioactive Wear Measurement

We have used radioactive tracer technology (RATT®) for over 50 years to make highly accurate and sensitive, real-time wear measurements in operating engines and other mechanical systems. Friction and wear are typically measured in engines to evaluate lubricant chemistries, component design, and...

www.swri.org

SwRI adds unique, efficient engine wear testing rig

Southwest Research Institute recently added an additional single cam rig (SCR) to its considerable array of tribology testing equipment. The rig, which investigates wear mechanisms in engine valvetrain components, was designed and created by SwRI staff led by Staff Engineer Dr. Peter Lee.

www.swri.org

Yes, residual wear metals that are inevitably in the oil that remains in the engine--just like the additive elements remain as shown in my image I posted.

 

[CarbonSteel]

I think maybe your referring to this thread?

Another "Taxi" Study: Relationship of Engine Bearing Wear and Oil Rheology 872128

1987-11-01 Relationship of Engine Bearing Wear and Oil Rheology 872128 Member OVERKILL referred to this SAE paper, another Taxi test. It is from a 1987 published paper but I felt it was worth reviewing: One premise they stated was: ...it is not clear that thicker oil films will lead to less...

bobistheoilguy.com

My guess is things have changed a bit since 1987?

No, there have been a number of members state that wear increases after an OC, I am questioning if it really does or if it is due to metals in the oil that remains in the engine.

 

[ZeeOSix]

Yes, residual wear metals that are inevitably in the oil that remains in the engine--just like the additive elements remain as shown in my image I posted.

No, there have been a number of members state that wear increases after an OC, I am questioning if it really does or if it is due to metals in the oil that remains in the engine.

If any residual wear metals are left in the engine after an oil change, it's just what's supspended in the old left over oil, or what's fallen out in the pan that basically stays where it sits even as the engine runs. Why would that left over residual wear metal all of a sudden show up right after an oil change if it wasn't there right before the oil change? If there is more wear after an oil change, it's most likely due to stripping of the AF/AW tribofilm factor.

 

[CarbonSteel]

If any residual wear metals are left in the engine after an oil change, it's just what's supspended in the old left over oil, or what's fallen out in the pan that basically stays where it sits even as the engine runs. Why would that left over residual wear metal all of a sudden show up right after an oil change if it wasn't there right before the oil change? If there is more wear after an oil change, it's most likely due to stripping of the AF/AW tribofilm factor.

That's my point, it doesn't just show up, just like the additive pack elements from a previous oil (that are not in the new oil) don't just show up--they are already there in the residual oil. The new oil picks it up as it is mixed with the old oil.

As the new oil gets time and miles on it, the wear metal concentrations level off and thus gives the impression of more wear at the onset of a new OC.

 

[ZeeOSix]

That's my point, it doesn't just show up, just like the additive pack elements from a previous oil (that are not in the new oil) don't just show up--they are already there in the residual oil. The new oil picks it up as it is mixed with the old oil.

As the new oil gets time and miles on it, the wear metal concentrations level off and thus gives the impression of more wear at the onset of a new OC.

I don't think the studies that try to determine if the wear increases with an oil change use a Blackstone type of UOA. They are probably using much more sophisticated test methods.

The longer the oil is ran, the more cumulative wear metals should be in the oil. So how could the wear metals ppm increase right after an oil change if most of those wear metals were removed by changing the oil? If a really good UOA was done at an oil change (say with 10,000 miles on the oil), and then again shortly after an oil change with fresh oil (say with 2000 miles on the oil), and the ppm of wear metals rate increased compared to the 10,000 mile rate it couldn't really be from left over residual oil because that volume of oil is very small compared to the volume of the used oil removed at with the oil change. Maybe a baseline UOA should be done like 10 miles after the oil change and compare the ppm rate increase from that point forward to null out any "residual oil effects".

 

[CarbonSteel]

I don't think the studies that try to determine if the wear increases with an oil change use a Blackstone type of UOA. They are probably using much more sophisticated test methods.

The longer the oil is ran, the more cumulative wear metals should be in the oil. So how could the wear metals ppm increase right after an oil change if most of those wear metals were removed by changing the oil? If a really good UOA was done at an oil change (say with 10,000 miles on the oil), and then again shortly after an oil change with fresh oil (say with 2000 miles on the oil), and the ppm of wear metals rate increased compared to the 10,000 mile rate it couldn't really be from left over residual oil because that volume of oil is very small compared to the volume of the used oil removed at with the oil change. Maybe a baseline UOA should be done like 10 miles after the oil change and compare the ppm rate increase from that point forward to null out any "residual oil effects".

If all of this is true, they why in the image I posted is the sodium from the add pack that high from such a small amount of oil that remains?

Two OCs later and it is still there and the two OCs afterwards were not short. What I'm suggesting is if the add pack elements carry over, then why wouldn't the wear metals? Thereby creating the perception that wear is increasing after an OC.

I would assume that more sophisticated tests are ran, but I would also wonder if the engines were completely flushed to remove all residuals before running the next oil in the test to see the wear increases.

 

[ZeeOSix]

Did you have a VOA of the Kendall so you knew where it's baseline was? Why are most of the add pack compounds higher on the 2nd run of the Kendall GT-1? It can't be from residual GT-1 oil if that residual oil had the same ppm of those compounds.

What was the VOA of sodium on the Mobil? The level of sodium can be due to other factors besides what was in a VOA before use.

What happened with the Magnesium between run 1 and run 2 of the GT-1?

Look at the iron ppm. There was way less miles put on the Mobil oil. So look at the miles per ppm rate.

Mobil: 3947/8 = 493 miles/ppm
GT-1 Run 1: 9245/15 = 616 miles/ppm
GT-1 Run 2: 8196/12 = 683 miles/ppm

The wear rate was actually higher on the Mobil and went down with run 1 of GT-1, then went down slightly more with run 2 of GT-1. The difference between run 1 and run 2 of GT-1 isn't much, so it's maybe possible that some of the Mobil residual bumped the run 1 of GT-1 up slightly. But this is a small sample of data, and who knows the accuracy of the UOA data. You could probably do 10 UOAs on the same exact oil sample and get some spread on these numbers.

 

[billt460]

"Wear increases after oil change"? Has anyone worn out an engine from changing their oil too much? That's like saying body odor increases after showering. Perhaps if you put on the same old smelly clothes...... Or leave the same old dirty oil filter in place.

 

[demarpaint]

If any residual wear metals are left in the engine after an oil change, it's just what's supspended in the old left over oil, or what's fallen out in the pan that basically stays where it sits even as the engine runs. Why would that left over residual wear metal all of a sudden show up right after an oil change if it wasn't there right before the oil change? If there is more wear after an oil change, it's most likely due to stripping of the AF/AW tribofilm factor.

My bet would be the remaining oil that didn't drain and has wear metals in suspension gets mixed in with the new oil after a few seconds of the engine running. That oil in comparison to fresh oil has a higher % of wear metals in it, just enough to show an increase once mixed in. That imo would explain a slight increase in wear #'s after an oil change.

 

[ZeeOSix]

My bet would be the remaining oil that didn't drain and has wear metals in suspension gets mixed in with the new oil after a few seconds of the engine running. That oil in comparison to fresh oil has a higher % of wear metals in it, just enough to show an increase once mixed in. That imo would explain a slight increase in wear #'s after an oil change.

You'd have to do a UOA like 10 miles into the new OCI to get a starting baseline. But what would that UOA show if the left over oil had say 8 ppm of iron when its volume was say only 10% of the total new OCI volume (1/2 qt of left behind old oil mixed with 5 qts of new oil). In that case, the ppm of the mix should be 1/10 of the dirty oil, or less than 1 ppm. That ppm level would be lost in the accuracy/noise level of a UOA done 8000 miles later.

 

[demarpaint]

You'd have to do a UOA like 10 miles into the new OCI to get a starting baseline. But what would that UOA show if the left over oil had say 8 ppm of iron when its volume was say only 10% of the total new OCI volume (1/2 qt of left behind old oil mixed with 5 qts of new oil). In that case, the ppm of the mix should be 1/10 of the dirty oil, or less than 1 ppm. That ppm level would be lost in the accuracy/noise level of a UOA done 8000 miles later.

Good point, thanks. There are a lot of variables to consider. I think this additional wear we speak of is a moot point, a non-event. A UOA is pretty much useless for determining wear, which has been mentioned countless times here.

 

[ZeeOSix]

A UOA is pretty much useless for determining wear, which has been mentioned countless times here.

Yeah, especially when trying to compare only 2 or 3 UOAs down to the resolution of 1 ppm. I'd like to see the same collected sample of oil ran 10 times through the same test machines in the same lab by the same operator to see the repeatability spread. Then run it through 10 diffetent labs to see the accuracy comparisons between labs.

 

[High Performance Lubricants]

This.

I always recommend taking a reference sample when beginning a UOA program. This should be taken within the first hundred miles. At that point you will see whatever residual material there is from the previous change. There is a large variation between vehicles. I have seen vehicles that hold a full gallon of oil, and others that have very little residual oil. The reference sample solves this, and in my opinion is the larger cause of this “scenario” than any tribofilm variation. It is such an easy thing to understand your true starting point.

 

[demarpaint]

This.

I always recommend taking a reference sample when beginning a UOA program. This should be taken within the first hundred miles. At that point you will see whatever residual material there is from the previous change. There is a large variation between vehicles. I have seen vehicles that hold a full gallon of oil, and others that have very little residual oil. The reference sample solves this, and in my opinion is the larger cause of this “scenario” than any tribofilm variation. It is such an easy thing to understand your true starting point.

I think the additional wear right after an oil change is blown out of proportion. As you mentioned some vehicles hold more residual oil than others, then you have the time the oil was allowed to drain. Some people allow a few minutes, others hours or even overnight. You need a starting point.

 

[High Performance Lubricants]

Aside from the west issue this approach will also help you when trying to look at the viscosity on fuel dilutors. A simple approach to help determine dilution vs shear.