Hi guys, I had a quick question. If synthetic oil is designed to NOT breakdown, in theory, can't we only just change the oil filter and let the filter clean out this oil instead of swapping it?
Do you really EVER have to change synthetic oil?
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Welcome! Good question for a first post.
No, syn will eventually break down.
Now I back away and let the REAL experts chime in.
No, syn will eventually break down.
Now I back away and let the REAL experts chime in.
Member TIG1 uses Mobil 1 0w20 and goes 10,000 oci
AZjeff
$50 Site Donor 2023
Originally Posted By: car51
Member TIG1 uses Mobil 1 0w20 and goes 10,000 oci
What's special about that? Our RAV4 specifies 0W20 and that OCI. You mean 100,000 maybe?
Member TIG1 uses Mobil 1 0w20 and goes 10,000 oci
What's special about that? Our RAV4 specifies 0W20 and that OCI. You mean 100,000 maybe?
Because the additive package will become depleted over the running time of the engine. Somewhere out there around 5~25K the additives would be used up and then you are into acids in the oil w/o any way to neutralize them ...
Running premium filters, and maybe a by-pass filter system, you could keep the oil visually clean. But it would still be chemically contaminated by combustion by-products ...
Running premium filters, and maybe a by-pass filter system, you could keep the oil visually clean. But it would still be chemically contaminated by combustion by-products ...
1. Light/medium duty automotive application filtration systems are not even close in terms of particulate size to remove soot. You need by-pass filtration for that.
2. You can't filter fuel out of oil.
3. The oil looses its TBN and becomes acidic as it is more and more contaminated.
In other words, the answer is no.
2. You can't filter fuel out of oil.
3. The oil looses its TBN and becomes acidic as it is more and more contaminated.
In other words, the answer is no.
Kind of a good question, as some do that with the bypass filters, so maybe with a really good filter like a fram ultra, and changing it and topping off the oil every 5000 miles or even less???? But then even so, probably not the bes idea if you want the engine to last 200k or more. But then it may depend on the type of driving you do also. I had an uncle that back in the early 60's had a 59 ford 6 cyl. stick, that he drove a 80+ mile trip to work and back every day. He never changed the oil, just the filter and kept the oil full. He would run them 100k and drop a new (rebuilt) engine in. And of course the oil those days wasn't nearly as good as today, and no synthetic.
Surprised this hasn't been brought up:
http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/mobil1.html
I think they went 18k on 2002 vintage Mobil 1
http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/mobil1.html
I think they went 18k on 2002 vintage Mobil 1
You can do it. I do not find oil changes to be so expensive that I would take the risk.
Originally Posted By: AZjeff
Originally Posted By: car51
Member TIG1 uses Mobil 1 0w20 and goes 10,000 oci
What's special about that? Our RAV4 specifies 0W20 and that OCI. You mean 100,000 maybe?
What's special about what I do for OCIs is that I have been doing 10K OCIs for 37 years with M1. Others have done that, but not many.
Originally Posted By: car51
Member TIG1 uses Mobil 1 0w20 and goes 10,000 oci
What's special about that? Our RAV4 specifies 0W20 and that OCI. You mean 100,000 maybe?
What's special about what I do for OCIs is that I have been doing 10K OCIs for 37 years with M1. Others have done that, but not many.
Originally Posted By: BrocLuno
Because the additive package will become depleted over the running time of the engine. Somewhere out there around 5~25K the additives would be used up and then you are into acids in the oil w/o any way to neutralize them ...
Running premium filters, and maybe a by-pass filter system, you could keep the oil visually clean. But it would still be chemically contaminated by combustion by-products ...
Right...the additives get depleted, but the oil molecules themselves are just fine.
Because the additive package will become depleted over the running time of the engine. Somewhere out there around 5~25K the additives would be used up and then you are into acids in the oil w/o any way to neutralize them ...
Running premium filters, and maybe a by-pass filter system, you could keep the oil visually clean. But it would still be chemically contaminated by combustion by-products ...
Right...the additives get depleted, but the oil molecules themselves are just fine.
Looks like you've got some good answers already, but the additives do break down especially ZDDP which is important for anti wear. Also oxidation causes the oil to thicken over time eventually rendering it too thick to flow well enough to lubricate under all conditions before eventually leading to sludge.
If you have time check out this
ZDP Depletion and GM Oil life monitor
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=130036
If you have time check out this
ZDP Depletion and GM Oil life monitor
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=130036
Can't figure out if it's a serious post or trolling.
MolaKule
Staff member
Originally Posted By: oil_dude08
...If synthetic oil is designed to NOT breakdown...
That premise is questionable at best.
It is not that we design formulated oils to break-down or not break-down.
We design oils to last as long as possible based on the performance expectations.
But the physio-chemical facts are that in an ICE, and when subjected to heat and oxidation and contaminants, the oil does degrade, and thus must be changed.
How often the oil must be changed depends greatly on the how well the specific oil and engine play together.
Stating "peanut-buttering" rules for OCI's is ridiculous. One must consider the whole system and its interactions.
...If synthetic oil is designed to NOT breakdown...
That premise is questionable at best.
It is not that we design formulated oils to break-down or not break-down.
We design oils to last as long as possible based on the performance expectations.
But the physio-chemical facts are that in an ICE, and when subjected to heat and oxidation and contaminants, the oil does degrade, and thus must be changed.
How often the oil must be changed depends greatly on the how well the specific oil and engine play together.
Stating "peanut-buttering" rules for OCI's is ridiculous. One must consider the whole system and its interactions.
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MolaKule
Staff member
Originally Posted By: maximus
Many gas turbine engine have no OCI. Oil is simply replaced via attrition. Of course in a turbine power plant, oil isn't subjected to combustion, kinda like ATF.
However, the bearing cells are subjected to very high temp conditions and loads, hence the need for special anti-oxidants and AW additives.
And true, due to replenishment upon attrition, these additives get refreshed.
Many gas turbine engine have no OCI. Oil is simply replaced via attrition. Of course in a turbine power plant, oil isn't subjected to combustion, kinda like ATF.
However, the bearing cells are subjected to very high temp conditions and loads, hence the need for special anti-oxidants and AW additives.
And true, due to replenishment upon attrition, these additives get refreshed.
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This is what would look like if you don't change your oil, synthetic or dino.
A BMW engine with too long OCI, even with synthetic oil.
A BMW engine with too long OCI, even with synthetic oil.
Wow. For real?
Originally Posted By: HTSS_TR
This is what would look like if you don't change your oil, synthetic or dino.
A BMW engine with too long OCI, even with synthetic oil.
Nobody knows theaverage oci these engines had gotten... 15k once 20k twice, a few 30k after all that? Assuming synthetic in this case.
This is what would look like if you don't change your oil, synthetic or dino.
A BMW engine with too long OCI, even with synthetic oil.
Nobody knows theaverage oci these engines had gotten... 15k once 20k twice, a few 30k after all that? Assuming synthetic in this case.
All oil oxidizes. Synthetic just takes a little longer than mineral oil to oxidize....
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