Oil Level Change Weirdness
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Originally Posted By: CharlieBauer
Be much easier to understand the graph if the y axis was oil qty. Then have two curves. 1 for oil level and 1 for oil consumption.
When I have some time I'll also make some graphs of dipstick oil level vs miles on the oil.
Be much easier to understand the graph if the y axis was oil qty. Then have two curves. 1 for oil level and 1 for oil consumption.
When I have some time I'll also make some graphs of dipstick oil level vs miles on the oil.
You could avoid the issue of possible dipstick non-linearity by adding oil back to the original point on the dipstick each time you check, and keep track of how much is added.
Originally Posted By: Rand
How much oil is actually used? try going until the add mark(without adding before) and let us know the miles
The oil level only goes down ~1/2 quart between changes. So I won't run it long enough to hit the "Add" mark. As mentioned earlier, I have verified that 1.0 qt does take the level from "Add" to "Full" when cold. I just need to verify dipstick linearity.
How much oil is actually used? try going until the add mark(without adding before) and let us know the miles
The oil level only goes down ~1/2 quart between changes. So I won't run it long enough to hit the "Add" mark. As mentioned earlier, I have verified that 1.0 qt does take the level from "Add" to "Full" when cold. I just need to verify dipstick linearity.
Originally Posted By: OilUzer
Originally Posted By: ZeeOSix
Originally Posted By: OilUzer
FYI
I asked a question regarding oil burning off or evaporating quicker in the first 500-1000 miles ...
From MotoTribologist (sp?):
"Evaporation rates generally start high and level off over time as less and less volatile material remains in the bulk of the oil due to said evaporation."
however your observation is different!
Maybe due to more than one thing going on at the same time in the first 1000 miles.
Actually the later part of your observation (based on your charts), is same as what MotoTribologist was saying as far oil burning "leveling off" ...
The first part of your graph (the hump) however may not look very conventional and looks inverted. This is based on my experience but I never collected this level of data & details.
It's actually the exact opposite of what would be expected. The leveling off should be toward less consumption than the initial rate, not more. The rate is nil to begin with and after 1K miles it skyrockets and settles at the rapid rate of loss. (All relative to the original rate though, since 1 qt for 5K miles isn't extreme from my experience.)
Perhaps the byproducts of the oxidation are more volatile somehow?
Originally Posted By: ZeeOSix
Originally Posted By: OilUzer
FYI
I asked a question regarding oil burning off or evaporating quicker in the first 500-1000 miles ...
From MotoTribologist (sp?):
"Evaporation rates generally start high and level off over time as less and less volatile material remains in the bulk of the oil due to said evaporation."
however your observation is different!
Maybe due to more than one thing going on at the same time in the first 1000 miles.
Actually the later part of your observation (based on your charts), is same as what MotoTribologist was saying as far oil burning "leveling off" ...
The first part of your graph (the hump) however may not look very conventional and looks inverted. This is based on my experience but I never collected this level of data & details.
It's actually the exact opposite of what would be expected. The leveling off should be toward less consumption than the initial rate, not more. The rate is nil to begin with and after 1K miles it skyrockets and settles at the rapid rate of loss. (All relative to the original rate though, since 1 qt for 5K miles isn't extreme from my experience.)
Perhaps the byproducts of the oxidation are more volatile somehow?
Originally Posted By: MotoTribologist
It's actually the exact opposite of what would be expected. The leveling off should be toward less consumption than the initial rate, not more.
Perhaps the byproducts of the oxidation are more volatile somehow?
That's what I was thinking based on my observation with different cars and oil. Basically more oil loss at the beginning (e.g the first 400-1K miles) then the loss levels off and also lower relative to beginning.
If the OP graph was "used quarts vs. mile" (instead of miles per quart) and looked exactly the same, the general shape of it would make more sense. the graph looks inverted!
Maybe other things are at play here! Can you expand on "perhaps the byproducts of oxidation are more volatile somehow?"
It's actually the exact opposite of what would be expected. The leveling off should be toward less consumption than the initial rate, not more.
Perhaps the byproducts of the oxidation are more volatile somehow?
That's what I was thinking based on my observation with different cars and oil. Basically more oil loss at the beginning (e.g the first 400-1K miles) then the loss levels off and also lower relative to beginning.
If the OP graph was "used quarts vs. mile" (instead of miles per quart) and looked exactly the same, the general shape of it would make more sense. the graph looks inverted!
Maybe other things are at play here! Can you expand on "perhaps the byproducts of oxidation are more volatile somehow?"
Originally Posted By: OilUzer
Can you expand on "perhaps the byproducts of oxidation are more volatile somehow?"
Not really, no. Oxidation is just the only other thing that should be happening over the time frame. Though it should be making heavier compounds, not lighter.
Other than fuel dilution, which the OP says is definitely not happening, I can't think of anything off the top of my head that would increase the consumption that rapidly. 1/5 of a quart for every 1000 miles isn't all that much, but still it's a weird correlation.
Can you expand on "perhaps the byproducts of oxidation are more volatile somehow?"
Not really, no. Oxidation is just the only other thing that should be happening over the time frame. Though it should be making heavier compounds, not lighter.
Other than fuel dilution, which the OP says is definitely not happening, I can't think of anything off the top of my head that would increase the consumption that rapidly. 1/5 of a quart for every 1000 miles isn't all that much, but still it's a weird correlation.
A car of mine does something similar. Recommended OCI is 8000km, at oil change time the oil is reaching the high mark on the dipstick. It stays there for about the first 3500-4000km. Then by 6000km it drops to the low level on the dipstick. Then I top up with nearly 1 quart back to the the high level and it will stay there until 8000-9000km.
I have no explanation on why most of the oil would disappear mid-OCI and not at the beginning or the end of it.
I have no explanation on why most of the oil would disappear mid-OCI and not at the beginning or the end of it.
A graph of the cold oil level vs vehicle mileage (x-axis) was added for both Oil Fill #1 and Oil Fill #2. 100% oil level is the "Full" mark on the dipstick, and 0% oil level is the "Add" mark on the dipstick. It's 1.0 qts between the Add and Full marks.
The added graph shows that the oil level stayed pretty constant until around 600~700 miles were put on the oil. That's why you see the 'hump' on the Oil Use (Mi/Qt) graph - if the oil level never went down the hump would continue upwards on the Oil Use (Mi/Qt) graph. Then the hump disappears as the oil level starts to go down after the 600~700 mile mark.
Oil Fill #1
Oil Fill #2
The added graph shows that the oil level stayed pretty constant until around 600~700 miles were put on the oil. That's why you see the 'hump' on the Oil Use (Mi/Qt) graph - if the oil level never went down the hump would continue upwards on the Oil Use (Mi/Qt) graph. Then the hump disappears as the oil level starts to go down after the 600~700 mile mark.
Oil Fill #1
Oil Fill #2
You're basically seeing a 0.2 qt anomaly at the full level, where the oil level appears to stay constant for a while. I'm pretty sure it has nothing to do with anything other than the geometry of your oil pan. Chances are that the cross section of your oil pan suddenly widens at the full level and that's where the 0.2 qt goes in. For example, see this oil pan for the Honda K engine:
What is your car? Perhaps we can find a picture of your oil pan, which could explain this.
Here are the cross sections for the Toyota 2ZR-FE engine:
Therefore, I wouldn't worry about this. Perhaps you can pinpoint the cause of your oil consumption and see if higher viscosity and/or lower NOACK helps.
What is your car? Perhaps we can find a picture of your oil pan, which could explain this.
Here are the cross sections for the Toyota 2ZR-FE engine:
Therefore, I wouldn't worry about this. Perhaps you can pinpoint the cause of your oil consumption and see if higher viscosity and/or lower NOACK helps.
Originally Posted By: Gokhan
... Here are the cross sections for the Toyota 2ZR-FE engine: ...
According to that illustration, the height at which the cross-section suddenly increases is about the same height at which the big ends would dip into the oil.
That's an interesting page because I have the closely related 2ZR-FXE.
... Here are the cross sections for the Toyota 2ZR-FE engine: ...
According to that illustration, the height at which the cross-section suddenly increases is about the same height at which the big ends would dip into the oil.
That's an interesting page because I have the closely related 2ZR-FXE.
Originally Posted By: Gokhan
I wouldn't worry about this. Perhaps you can pinpoint the cause of your oil consumption and see if higher viscosity and/or lower NOACK helps.
I'm not worried about it ... I'm just showing what I've seen with the oil level recordings. It could be the oil pan geometry ... but every engine is different, and seems engineers wouldn't make the design so the dipstick is non-linear in level indication between the "Add" and "Full" marks.
I'll know more after I verify the dipstick linearity and also use a different oil with lower Noack, which I plan on doing in a month or so with the next oil change to see if the same trend occurs. I'm betting an oil with a lower Noack will probably show a different trend.
I wouldn't worry about this. Perhaps you can pinpoint the cause of your oil consumption and see if higher viscosity and/or lower NOACK helps.
I'm not worried about it ... I'm just showing what I've seen with the oil level recordings. It could be the oil pan geometry ... but every engine is different, and seems engineers wouldn't make the design so the dipstick is non-linear in level indication between the "Add" and "Full" marks.
I'll know more after I verify the dipstick linearity and also use a different oil with lower Noack, which I plan on doing in a month or so with the next oil change to see if the same trend occurs. I'm betting an oil with a lower Noack will probably show a different trend.
Originally Posted By: CR94
Originally Posted By: Gokhan
... Here are the cross sections for the Toyota 2ZR-FE engine: ...
According to that illustration, the height at which the cross-section suddenly increases is about the same height at which the big ends would dip into the oil.
That's an interesting page because I have the closely related 2ZR-FXE.
Looking at those engine cross sections, it looks like the end of the dipstick is well below the stepped section of the oil pan, so shouldn't cause much non-linearity on the dipstick reading.
Originally Posted By: Gokhan
... Here are the cross sections for the Toyota 2ZR-FE engine: ...
According to that illustration, the height at which the cross-section suddenly increases is about the same height at which the big ends would dip into the oil.
That's an interesting page because I have the closely related 2ZR-FXE.
Looking at those engine cross sections, it looks like the end of the dipstick is well below the stepped section of the oil pan, so shouldn't cause much non-linearity on the dipstick reading.
Originally Posted By: nap
A car of mine does something similar. Recommended OCI is 8000km, at oil change time the oil is reaching the high mark on the dipstick. It stays there for about the first 3500-4000km. Then by 6000km it drops to the low level on the dipstick. Then I top up with nearly 1 quart back to the the high level and it will stay there until 8000-9000km.
I have no explanation on why most of the oil would disappear mid-OCI and not at the beginning or the end of it.
interesting! I had a similar experience couple of times that i remember mid oci I had to add oil. Not much loss before and not much after ...
in both instances, it was after a 3-4 hours trip with relatively higher than normal rpm/speed and one time if was relatively hot weather as well.
I attributed it to high rpm/heat but it's under my radar. Trying to duplicate again... but different variables involved.
Did you run the car hard before the oil loss?
A car of mine does something similar. Recommended OCI is 8000km, at oil change time the oil is reaching the high mark on the dipstick. It stays there for about the first 3500-4000km. Then by 6000km it drops to the low level on the dipstick. Then I top up with nearly 1 quart back to the the high level and it will stay there until 8000-9000km.
I have no explanation on why most of the oil would disappear mid-OCI and not at the beginning or the end of it.
interesting! I had a similar experience couple of times that i remember mid oci I had to add oil. Not much loss before and not much after ...
in both instances, it was after a 3-4 hours trip with relatively higher than normal rpm/speed and one time if was relatively hot weather as well.
I attributed it to high rpm/heat but it's under my radar. Trying to duplicate again... but different variables involved.
Did you run the car hard before the oil loss?
I had a 1997 Chevy Malibu with the 350ci engine that I bought new. When taken on the highway the oil would drop to the halfway mark on the dipstick between gas fill ups. I would top it off and move on. Back down to half full at the next gas fill up. Finally I just left the oil at the half full to see if it would go to the low mark at the next gas fill up. It never did. So I just left the oil at the half full for the rest of it's life. I never could explain this to myself. Probably had the wrong dipstick.
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