No. The oil all mixes. The very oldest oil will still be there in small quantities even after your last topoff. The oldest oil will never completely leave. It does not burn out starting at the oldest and working toward the newest. Instead, it all mixes together. It is like when I was a chef. If you mix old food with new food, then the entire container is only as new as the oldest food in it. Likewise, your total oil makeup will only be as new as the very oldest oil in it, which could be years old.
Never change oil, only filter?
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Originally Posted By: caveatipse
No. The oil all mixes. The very oldest oil will still be there in small quantities even after your last topoff. The oldest oil will never completely leave. It does not burn out starting at the oldest and working toward the newest. Instead, it all mixes together. It is like when I was a chef. If you mix old food with new food, then the entire container is only as new as the oldest food in it. Likewise, your total oil makeup will only be as new as the very oldest oil in it, which could be years old.
Well you don't worry about that, btw shouldn't you be changing your oil now. You must be close to your 1000 mile OCI.
No. The oil all mixes. The very oldest oil will still be there in small quantities even after your last topoff. The oldest oil will never completely leave. It does not burn out starting at the oldest and working toward the newest. Instead, it all mixes together. It is like when I was a chef. If you mix old food with new food, then the entire container is only as new as the oldest food in it. Likewise, your total oil makeup will only be as new as the very oldest oil in it, which could be years old.
Well you don't worry about that, btw shouldn't you be changing your oil now. You must be close to your 1000 mile OCI.
What if there is a leak you are constantly topping off?
Awsome thread, I have often wondered about this myself. If the car is paid off, and you arn't worried about selling it. I say give it a try for a year and do a UOA at the end of the year and post it.
Also, you may want to eventually try replacing the filter every 5,000 miles just so that you get larger particles out and have extra make up oil.
I say do it and let us know how it goes. If you start having trouble with it you can always Auto RX or MMO it, choose your posion.
Also, you may want to eventually try replacing the filter every 5,000 miles just so that you get larger particles out and have extra make up oil.
I say do it and let us know how it goes. If you start having trouble with it you can always Auto RX or MMO it, choose your posion.
Originally Posted By: JonnyHotcakes
What if there is a leak you are constantly topping off?
If you're losing or using 1 qt of oil/1000 miles it makes no difference, the math would be the same as per the above example. The leak situtaion would be better for the engine/cat since the oil would be lost externally vs. consumed. JMO
What if there is a leak you are constantly topping off?
If you're losing or using 1 qt of oil/1000 miles it makes no difference, the math would be the same as per the above example. The leak situtaion would be better for the engine/cat since the oil would be lost externally vs. consumed. JMO
Originally Posted By: demarpaint
Originally Posted By: JonnyHotcakes
What if there is a leak you are constantly topping off?
If you're losing or using 1 qt of oil/1000 miles it makes no difference, the math would be the same as per the above example. The leak situtaion would be better for the engine/cat since the oil would be lost externally vs. consumed. JMO
I only ask because a car in my family that I maintain and use for long hauls as it's great on gas is leaking oil at a rate that is higher then a quart per 1k.
It's been doing this for over a year and a half and I've only changed the filter and topped off. It seems to be doing quite well with the regimen, it is routinely ran for long trips by me, and when used by family members it gets short hops in the extreme cold. Always starts up, runs quiet and smooth, great mileage.
Originally Posted By: JonnyHotcakes
What if there is a leak you are constantly topping off?
If you're losing or using 1 qt of oil/1000 miles it makes no difference, the math would be the same as per the above example. The leak situtaion would be better for the engine/cat since the oil would be lost externally vs. consumed. JMO
I only ask because a car in my family that I maintain and use for long hauls as it's great on gas is leaking oil at a rate that is higher then a quart per 1k.
It's been doing this for over a year and a half and I've only changed the filter and topped off. It seems to be doing quite well with the regimen, it is routinely ran for long trips by me, and when used by family members it gets short hops in the extreme cold. Always starts up, runs quiet and smooth, great mileage.
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Some cars have those problems. If its not worth fixing or the repair is being put off till a later date then topping them off and changing a filter will keep'em going for a long time.
sorry if i'm resurrecting a dead thread, but i'm new...
i think you should just use cheap oil from farm/fleet or autozone brand or whatever is on sale in bulk and change it at a reasonable interval while continuing to top it off
i would think brand new oil (even if cheaper quality) every now and then would outweigh a superior oil that's got parts that never get flushed out. i don't think there's any substitute for a full drain of your oil since you simply can't count on the complete and even burn off of all the debris and contaminants that are designed to be suspended in the oil.
i think you should just use cheap oil from farm/fleet or autozone brand or whatever is on sale in bulk and change it at a reasonable interval while continuing to top it off
i would think brand new oil (even if cheaper quality) every now and then would outweigh a superior oil that's got parts that never get flushed out. i don't think there's any substitute for a full drain of your oil since you simply can't count on the complete and even burn off of all the debris and contaminants that are designed to be suspended in the oil.
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Hi
At 1 quart in 1000 miles it would be OK if you did that 5000m distance within 6 months or less.
If it takes longer than 6 months to do the 5000 miles then I would do an extra filter changes ie every 3 months just to keep the oil fresh.
Make sure you keep the oil in the sump near the full line on the dipstick at all times to keep the concentration of contaminants as low as possible.
Perhaps you should top up every week or when it drops 300ml (or every 300 miles) below the dipstick full line. I would not wait for it to drop 1 quart practiising this regime.
Do a complete oil change every 12 months.
At 1 quart in 1000 miles it would be OK if you did that 5000m distance within 6 months or less.
If it takes longer than 6 months to do the 5000 miles then I would do an extra filter changes ie every 3 months just to keep the oil fresh.
Make sure you keep the oil in the sump near the full line on the dipstick at all times to keep the concentration of contaminants as low as possible.
Perhaps you should top up every week or when it drops 300ml (or every 300 miles) below the dipstick full line. I would not wait for it to drop 1 quart practiising this regime.
Do a complete oil change every 12 months.
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I also am an electrical engineer and actually build stuff. I would like to say thank you to the math guys that gave us the building blocks to do what we do. Being a math guy as you are and used to being able to "prove" things, dosent it get frustrating reading most of this oil stuff where there is very little "Proof". I very rarely see good conclusive tests with posted results and a good summary of the data. I believe oil companys do this on purpose so people can never really know.
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