What/Why/How do extended OCI damage the engine?
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Originally Posted By: Spetz
Does 10K oil not protect the engine as well as 6K oil?
Who said that extended OCI damage the engine? Many engine manufacturers certainly don't think so.
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From what I understand the oil gets diluted with fuel and there are wear items in the oil?
If you have a fuel dilution problem, then it's going to be an issue for your engine regardless if you run short or long OCI.
Does 10K oil not protect the engine as well as 6K oil?
Who said that extended OCI damage the engine? Many engine manufacturers certainly don't think so.
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From what I understand the oil gets diluted with fuel and there are wear items in the oil?
If you have a fuel dilution problem, then it's going to be an issue for your engine regardless if you run short or long OCI.
I've heard sulphuric acid builds up in the oil which can cause pitting and corrosion on the engine block. This would still be there regardless of whether the oil can still perform as an effective lubricant and the longer the OCI, the higher the concentration.
Could be wrong but that's what I've been told
Also the manufacturers recommendations tend to be dragged out as long as possible as environmental agencies tend to persuade them to make the interval as high as possible before it becomes dangerous, to cut back on oil usage and wastage.
The OCI in my manual was stretched to 15k but I do it at 7.5k. I stretched it out to 10k once and didn't like what I saw haha
They were also pushed by the enviros to recommend 5w30 to save fuel, but this caused early engine problems and was quickly changed back to 10w40!
Could be wrong but that's what I've been told
Also the manufacturers recommendations tend to be dragged out as long as possible as environmental agencies tend to persuade them to make the interval as high as possible before it becomes dangerous, to cut back on oil usage and wastage.
The OCI in my manual was stretched to 15k but I do it at 7.5k. I stretched it out to 10k once and didn't like what I saw haha
They were also pushed by the enviros to recommend 5w30 to save fuel, but this caused early engine problems and was quickly changed back to 10w40!
At some point in time, for a variety of reasons, oil starts to lose its ability to lubricate as well as it did when it was fresh.
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As with all things in life, the oil's ability to do its job is relative.
As oil ages the additives in the oil become depleted. The oil becomes saturated with combustion by-products and at some point will reach a level where these particulates become abrasive. The oil is subject to thermal cycling which leads to oxidation and nitration. Over time this causes the oil to become corrossive which leads to erosion on the engine components.
The structure of the oil also changes over time. As the molecules shear and re-bond and change shape they will eventually reach a point where they no-longer can retain their originial design properties. Once this happens the oil will usually degrade at a higher rate and will ultimately not be within the intended design parameters required to perform satisfactorily. Because of this phenomenon it is very difficult to say that one oil will last "X" number of miles while another will last "Y" number of miles. The declination of properties is simply not linear.
External environment also affects the oils ability to meet design parameters. Fuel dilution, fuel quality, engine efficieny, engine design, climate, etc, all play a role in how well and how long a motor oil will last.
So to address the original question you would have to define what is meant by extended drain interval. Any useage past the oils serviceable life will cause engine damage. The question to answer is how hard is my engine on oil. I've had engines that destroyed oil in as little as 4,000 miles and some that were cruising along at 15,000 miles. Oil brand and type wasn't really what set those limits.
As oil ages the additives in the oil become depleted. The oil becomes saturated with combustion by-products and at some point will reach a level where these particulates become abrasive. The oil is subject to thermal cycling which leads to oxidation and nitration. Over time this causes the oil to become corrossive which leads to erosion on the engine components.
The structure of the oil also changes over time. As the molecules shear and re-bond and change shape they will eventually reach a point where they no-longer can retain their originial design properties. Once this happens the oil will usually degrade at a higher rate and will ultimately not be within the intended design parameters required to perform satisfactorily. Because of this phenomenon it is very difficult to say that one oil will last "X" number of miles while another will last "Y" number of miles. The declination of properties is simply not linear.
External environment also affects the oils ability to meet design parameters. Fuel dilution, fuel quality, engine efficieny, engine design, climate, etc, all play a role in how well and how long a motor oil will last.
So to address the original question you would have to define what is meant by extended drain interval. Any useage past the oils serviceable life will cause engine damage. The question to answer is how hard is my engine on oil. I've had engines that destroyed oil in as little as 4,000 miles and some that were cruising along at 15,000 miles. Oil brand and type wasn't really what set those limits.
All vehicles when switched to an extended drain by the OEM have had the capacity of the sump increased.
Extending the drain period beyond the OEM recommendations without some monitoring or testing system is always a risk.
Check under what conditions the OEM manual says id recommended for a 15k interval.
For interest what was the sump capacity of the same model of your vehicle before the OCI was extended to 15k.
Extending the drain period beyond the OEM recommendations without some monitoring or testing system is always a risk.
Check under what conditions the OEM manual says id recommended for a 15k interval.
For interest what was the sump capacity of the same model of your vehicle before the OCI was extended to 15k.
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Originally Posted By: FowVay
As with all things in life, the oil's ability to do its job is relative.
Not to quote the whole of your post (which I agree with), the next point is that everything in life is on a probability curve, whether it be the batch variation of the oil that's used, the wear rates, dilution, and contamination that occur...was trying to explain to a junior engineer the other day that it doesn't matter how "careful" he is, he needs to be prepared to be a father...
Manufacturers play the odds, and choose where they want to live on the probability curve, and how far they want to stretch that with marketting.
Mitsubishi had 15,000km OCIs on their diesel utes, not because they had a better/more robust design, but the small probability of failure (that they couldn't blame on a customer) was offset by the vehicles that they sold to businesses who had 30-60% less days off the road for servicing.
Extended OCIs don't damage any engine per se, they just reduce the safety margin that you have at the end of the OCI...possibly to a zero, or negative impact.
As with all things in life, the oil's ability to do its job is relative.
Not to quote the whole of your post (which I agree with), the next point is that everything in life is on a probability curve, whether it be the batch variation of the oil that's used, the wear rates, dilution, and contamination that occur...was trying to explain to a junior engineer the other day that it doesn't matter how "careful" he is, he needs to be prepared to be a father...
Manufacturers play the odds, and choose where they want to live on the probability curve, and how far they want to stretch that with marketting.
Mitsubishi had 15,000km OCIs on their diesel utes, not because they had a better/more robust design, but the small probability of failure (that they couldn't blame on a customer) was offset by the vehicles that they sold to businesses who had 30-60% less days off the road for servicing.
Extended OCIs don't damage any engine per se, they just reduce the safety margin that you have at the end of the OCI...possibly to a zero, or negative impact.
There are several errors in the replies to this post. As long as the TBN stays above 1 (I would say 2) acid will not build up. There are additives to deal with the acid that is created. Over time the base oil will shear and oxidize. The extent to which this happens is normally related to the quality of the basestock. Fuel dilution is usually not a problem with an engine that is running properly (including fuel injectors). Any fuel that gets in should be burned off. However a leaky injector could cause an issue. Contaminants like iron and silicon do accumulate in the oil. The larger size particles will be filtered out. To a small extent the oil filter will do a better job of filtering filer particles as it fills up.
All of this is dependent upon the quality of the oil and condition of the engine.
Extended OCIs are certainly possible. I am running 18K on my Ram pickup with a Cummins diesel. But the oil sump is 12 QT, the oil is a top of the line Rotella T6, I do UOAs to see where I stand and the engine is a Cummins.
But if you have a worn engine, oil from the Dollar Store, coolant leak into the oil, air intake allowing dirt into engine, or many short trips then an extended OCI may not be wise.
All of this is dependent upon the quality of the oil and condition of the engine.
Extended OCIs are certainly possible. I am running 18K on my Ram pickup with a Cummins diesel. But the oil sump is 12 QT, the oil is a top of the line Rotella T6, I do UOAs to see where I stand and the engine is a Cummins.
But if you have a worn engine, oil from the Dollar Store, coolant leak into the oil, air intake allowing dirt into engine, or many short trips then an extended OCI may not be wise.
Originally Posted By: Donald
There are several errors in the replies to this post. As long as the TBN stays above 1 (I would say 2) acid will not build up.
Acid does continuously build up, which is manifested by the increasing TAN. Now the question is, at what point does it become harmful? Some say it's at a point when TAN intersects TBN. Others have different points of view on this.
There are several errors in the replies to this post. As long as the TBN stays above 1 (I would say 2) acid will not build up.
Acid does continuously build up, which is manifested by the increasing TAN. Now the question is, at what point does it become harmful? Some say it's at a point when TAN intersects TBN. Others have different points of view on this.
Depends upon the oil, the engine and how the car is driven.
The right oil in an undemanding application that's driven pretty easily and not strictly short-tripped could probably give 10K with some margin left over.
My '12 Accord will allow 10K or longer drains under the right driving conditions, for example. On my commute, I was seeing from 1K to 1.2K per 10% decline in oil life. On my wife's commute, which involves a lot more traffic, oil life declines at about 800 miles per 10%.
Change any variable and you change the useful service life of the oil.
Manufacturer's recommendations are usually pretty conservative for the US market at least.
The right oil in an undemanding application that's driven pretty easily and not strictly short-tripped could probably give 10K with some margin left over.
My '12 Accord will allow 10K or longer drains under the right driving conditions, for example. On my commute, I was seeing from 1K to 1.2K per 10% decline in oil life. On my wife's commute, which involves a lot more traffic, oil life declines at about 800 miles per 10%.
Change any variable and you change the useful service life of the oil.
Manufacturer's recommendations are usually pretty conservative for the US market at least.
Originally Posted By: 19jacobob93
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Also the manufacturers recommendations tend to be dragged out as long as possible as environmental agencies tend to persuade them to make the interval as high as possible before it becomes dangerous, to cut back on oil usage and wastage.
The OCI in my manual was stretched to 15k but I do it at 7.5k. I stretched it out to 10k once and didn't like what I saw haha
They were also pushed by the enviros to recommend 5w30 to save fuel, but this caused early engine problems and was quickly changed back to 10w40!
I don't know about your local, but one of the main driving forces in the longer oci's here is cost of ownership. Car makers have to compete with sticker price plus the cost of fuel and service for a given ownership interval. The US has cafe standards, which push efficiency, but there are also market pressures at work. Some of those buying high efficiency cars are tree hugging liberals, but as many are sold to businesses and cheap old conservatives who want to save some money.
...
Also the manufacturers recommendations tend to be dragged out as long as possible as environmental agencies tend to persuade them to make the interval as high as possible before it becomes dangerous, to cut back on oil usage and wastage.
The OCI in my manual was stretched to 15k but I do it at 7.5k. I stretched it out to 10k once and didn't like what I saw haha
They were also pushed by the enviros to recommend 5w30 to save fuel, but this caused early engine problems and was quickly changed back to 10w40!
I don't know about your local, but one of the main driving forces in the longer oci's here is cost of ownership. Car makers have to compete with sticker price plus the cost of fuel and service for a given ownership interval. The US has cafe standards, which push efficiency, but there are also market pressures at work. Some of those buying high efficiency cars are tree hugging liberals, but as many are sold to businesses and cheap old conservatives who want to save some money.
Logically extending fluid change intervals does NOT shorten engine life.
Not performing maintenance can shorten engine life.
Most all (but not ALL) engines will not a show a bit, a wit, or any difference at all between a 6K and 10K OCI with a good synthetic oil.
You are correct about one thing - fuel (raw and partially oxidized) in the oil is indeed the hardest thing on the oil and eventually the engine. Mostly in the form of varnish and contaminants. If your engine, diesel or gas, is blowing fuel past the rings, then extended OCI's should be monitored closely.
Not performing maintenance can shorten engine life.
Most all (but not ALL) engines will not a show a bit, a wit, or any difference at all between a 6K and 10K OCI with a good synthetic oil.
You are correct about one thing - fuel (raw and partially oxidized) in the oil is indeed the hardest thing on the oil and eventually the engine. Mostly in the form of varnish and contaminants. If your engine, diesel or gas, is blowing fuel past the rings, then extended OCI's should be monitored closely.
Originally Posted By: Spetz
As per title really.
Does 10K oil not protect the engine as well as 6K oil?
No.
As per title really.
Does 10K oil not protect the engine as well as 6K oil?
No.
I have been using 10K OCI's on every car I have maintained since the early 1990's. These included a 1989 Accord, 1990 Escort, 1993 Escort, 1999 Isuzu Oasis, 1999 Infiniti I30, and 2003 Toyota Highlander (2.4L). I had to change the oil pan gasket on the 93 Escort and the valve cover gasket on the 03 Highlander. I had to pull the valve cover on the 89 Accord at regular intervals for valve lash checks. None of these vehicles failed to be spotless and none had lubrication or compression related issues. All were kept to at least 150,000 miles (354,000 in the case of the Accord). I used whatever synthetic oil was on sale, though, now with Wal Mart's consistent pricing for most 5 qt jugs I stick with 1-3 name brands.
There is just way too much effort being put into what brand and OCI to use. Pick one, go with 10,000 miles, and worry about something else.
There is just way too much effort being put into what brand and OCI to use. Pick one, go with 10,000 miles, and worry about something else.
I went 12k miles in our 07 Civic EX, which was 2x what Honda suggests as the recommended oil change interval (the maintenance light came on regularly at 6-7k based on our driving conditions.
The lab results showed that I could go longer if I wanted too as there was still a decent amount of TBN left.
Some engines require a short interval due to design, so you need to do some testing or at least view the results on an extended interval of the same engine from another member. So engines just aren't a good candidate for extended OCIs.
The lab results showed that I could go longer if I wanted too as there was still a decent amount of TBN left.
Some engines require a short interval due to design, so you need to do some testing or at least view the results on an extended interval of the same engine from another member. So engines just aren't a good candidate for extended OCIs.
Mostly reasonable answers here. Yet, with this, there really is no substitute for simply trying it out in fleet testing over time. http://papers.sae.org/2007-01-4133/ should be a must-read, even if you just read the summary. Ford/Conoco basically found that new fresh oil in an engine has the highest wear rates, yes, counterintuitive at first. I think the answer is to only change half your oil out about once or three times a year, then a complete change every 2 or 3 years. ... (There are other concerns, like the one I have in one vehicle: Short trips, oil seldom gets up to temperature! -- Can cause sludge to build up quickly.)
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This is why I always idle my engine for a good 10 minutes while I do cleanup, to not only allow the new oil to circulate but to also give it time to warm up and "break-in" so to speak, before any serious engine load is applied.
I think the topic is too complicated anyway and the tests that are posted are flawed and here's why... The longer the OCI, the more the filter gets clogged and therefor, the better it filters before reaching capacity. These tests that show used oil is getting better with age are simply showing that the oil is getting filtered better as the OIL FILTER ages.
If used oil is so much better, wouldn't all these professional racing teams be using some "pre-owned" racing oil off another car in their engines? Why are they all using FRESH, NEW oil? Don't they know the secret about old, dirty, black oil and that it works better?
or are they reusing that old oil from a prior race in that freshly rebuilt engine during another race? I doubt it.
I want to see some REAL testing of this so called MYTH.
How about someone runs new oil in an engine without an oil filter for 1,000 miles and then sample it.
Then drain the oil, run it through a filtration system to remove all wear metals and put it back into the engine and run it some more.
If that engine shows less wear the older the oil is, I'll believe it and will then proceed to reuse 3,000 mile old oil from fellow friends who bump it because they think its BAD. I'll put their 3,000 mile old oil into my $65,000 Lexus and sleep well at night, knowing that the older oil is protecting my engine way better then any new oil off the shelf and I'll laugh as I'll see people carrying new oil jugs to the checkout and think "sucker". Hahahaha.
Joke over. I'm gonna go change my oil with NEW lubricant...
I think the topic is too complicated anyway and the tests that are posted are flawed and here's why... The longer the OCI, the more the filter gets clogged and therefor, the better it filters before reaching capacity. These tests that show used oil is getting better with age are simply showing that the oil is getting filtered better as the OIL FILTER ages.
If used oil is so much better, wouldn't all these professional racing teams be using some "pre-owned" racing oil off another car in their engines? Why are they all using FRESH, NEW oil? Don't they know the secret about old, dirty, black oil and that it works better?
I want to see some REAL testing of this so called MYTH.
How about someone runs new oil in an engine without an oil filter for 1,000 miles and then sample it.
Then drain the oil, run it through a filtration system to remove all wear metals and put it back into the engine and run it some more.
If that engine shows less wear the older the oil is, I'll believe it and will then proceed to reuse 3,000 mile old oil from fellow friends who bump it because they think its BAD. I'll put their 3,000 mile old oil into my $65,000 Lexus and sleep well at night, knowing that the older oil is protecting my engine way better then any new oil off the shelf and I'll laugh as I'll see people carrying new oil jugs to the checkout and think "sucker". Hahahaha.
Joke over. I'm gonna go change my oil with NEW lubricant...
Originally Posted By: virginoil
All vehicles when switched to an extended drain by the OEM have had the capacity of the sump increased.
Or enhance the oil specification in one way or another, such as dexos1, ACEA specifications, and so forth. Certain oils are obviously more capable of handling an extended OCI than others.
All vehicles when switched to an extended drain by the OEM have had the capacity of the sump increased.
Or enhance the oil specification in one way or another, such as dexos1, ACEA specifications, and so forth. Certain oils are obviously more capable of handling an extended OCI than others.
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