Oil Change Intervals 3k vs Longer with full synthetic

When manufacturers recommend maintenance intervals we must remember the following: the manufacturer doesn't want you to keep the car ten plus years. There job after all is to sell you a new one. The manufacturer also makes it seem like the cost of ownership and maintenance will be less money by recommending longer intervals. This makes the buyer think " "wow this car won't cost me much to operate ". Plus they get government credit for providing environmentally friendly vehicles. Less oil changes, trans services and other services equals less waste fluids and less pollution. Just because they may recommend certain intervals does not mean it's what's best for the vehicles

The counterpoint to this is that manufacturers absolutely care about resale value. Toyota and Honda DEFINITELY benefit from return/repeat new car customers as they pass their 8+ year old car to their kids/family. They know no one wants to buy a car that is hard to off load when you've decided to move on (looking at you Tesla) or becomes a money pit that you can't really maintain as a beater/hand-me-down.

Also some manufacturers go to GREAT lengths to determine stringent testing protocols that result in outstanding fluid performance (looking at you VW/Audi, BMW, MB, Porsche, GM).

If you're using an oil that meets an extremely stringent specification (and doesn't stress degrade a system of your vehicle) you'll likely be fine with extended fluid intervals.
 
It surprises me when I hear about members here who have one of these Kia/Hyundai GDI vehicles that are so failure prone unless you change the oil at such low intervals. Didn’t they do any research before buying? There’s so many other choices they could have gone with that aren’t so sensitive to oil choice/interval.
The Hyundai/Kia problematic 4-cylinder engines seem to be MY2011 on, but I didn't start hearing about widespread problems with them until about 2018.

So, there was a window there where an informed consumer could have bought one in good faith, expecting they would be as good as the earlier H/K engines.

Several friends and acquaintances have experienced low-mileage H/K engine failures in the past year.
 
When manufacturers recommend maintenance intervals we must remember the following: the manufacturer doesn't want you to keep the car ten plus years. There job after all is to sell you a new one. The manufacturer also makes it seem like the cost of ownership and maintenance will be less money by recommending longer intervals. This makes the buyer think " "wow this car won't cost me much to operate ". Plus they get government credit for providing environmentally friendly vehicles. Less oil changes, trans services and other services equals less waste fluids and less pollution. Just because they may recommend certain intervals does not mean it's what's best for the vehicles
This is a great point that bears frequent repeating. The classic example is when Toyota went to 10,000 mi intervals. That decision was not made by the engineers. It was made by the marketing department. The engineers were overruled.
 
One must keep in mind that service intervals are driven by two things.

First and foremost, they are calculated to provide the absolute minimum servicing the vehicle needs to get it through the provided warranty. It’s kind of a ******** sales pitch that associates use to make you think you’re saving money.

Additionally, in recent years, the published extended service intervals are to satisfy the EPA and CAFE mandates allowing manufacturers to state that these vehicles are now designed to use less oils and lubricants. Using less oils and lubricants, at a longer interval, creates less waste.

A smart person will take whatever the manufacturer is stating and cut it in half or 1/3 if he or she desires to prolong the life of the vehicle to its fullest extent
 
The counterpoint to this is that manufacturers absolutely care about resale value. Toyota and Honda DEFINITELY benefit from return/repeat new car customers as they pass their 8+ year old car to their kids/family. They know no one wants to buy a car that is hard to off load when you've decided to move on (looking at you Tesla) or becomes a money pit that you can't really maintain as a beater/hand-me-down.

Also some manufacturers go to GREAT lengths to determine stringent testing protocols that result in outstanding fluid performance (looking at you VW/Audi, BMW, MB, Porsche, GM).

If you're using an oil that meets an extremely stringent specification (and doesn't stress degrade a system of your vehicle) you'll likely be fine with extended fluid intervals.
that would be very true if only CAFE and the ecological mandates do not exist.
Currently all manufactures care mostly about saving a drop of fuel and jeopardizing reliability by pushing new questionable tech into new models. Otherwise hefty fines are issued by regulators.

Let's not forget recent examples failing Tundra's new turbo engines after moving away from NA V8 due to the same same chase to save some fuel. How Toyota allowed this untested unproved engine in mass production, is very well understood. They're caring about CAFE more than about returning customers.
 
that would be very true if only CAFE and the ecological mandates do not exist.
Currently all manufactures care mostly about saving a drop of fuel and jeopardizing reliability by pushing new questionable tech into new models. Otherwise hefty fines are issued by regulators.

Let's not forget recent examples failing Tundra's new turbo engines after moving away from NA V8 due to the same same chase to save some fuel. How Toyota allowed this untested unproved engine in mass production, is very well understood. They're caring about CAFE more than about returning customers.
The Toyota turbo V6 failures were brought about due to debris left in the engine following machining. This is a direct result of the failure to clean and prep the engines prior to assembly. This is a breakdown of the established norms that are always to be in place prior to engine assembly. This is a human failure, not an engineering or sales or marketing failure that is driven toward fuel economy

It’s my opinion that if these Tundras were built in Japan, this would not have been an issue. I hate to say it, but the quality of many vehicles built and United States and Mexico is far lesser than those built in Japan.

We have a 2008 FJ that was built in Japan as they all are. I hate to say it, but it’s been the best vehicle I’ve ever owned. I also hate to admit it was quite a step buying a Japanese produced vehicle for me. Long time Chevy, long time Ford owner.
 
The Toyota turbo V6 failures were brought about due to debris left in the engine following machining. This is a direct result of the failure to clean and prep the engines prior to assembly. This is a breakdown of the established norms that are always to be in place prior to engine assembly. This is a human failure, not an engineering or sales or marketing failure that is driven toward fuel economy

It’s my opinion that if these Tundras were built in Japan, this would not have been an issue. I hate to say it, but the quality of many vehicles built and United States and Mexico is far lesser than those built in Japan.

We have a 2008 FJ that was built in Japan as they all are. I hate to say it, but it’s been the best vehicle I’ve ever owned. I also hate to admit it was quite a step buying a Japanese produced vehicle for me. Long time Chevy, long time Ford owner.
beside debris I am seeing reports issues with turbo, Leaking head seal, Waste gate issues
 
This is a great point that bears frequent repeating. The classic example is when Toyota went to 10,000 mi intervals. That decision was not made by the engineers. It was made by the marketing department. The engineers were overruled.
I don't think it's the interval itself that's the problem but rather Toyota's decision to run with a mileage counter instead of an iOLM, something that takes operating conditions into account. There are certainly conditions under which 10,000+ miles is attainable, the problem is of course that there are others under which it grossly exceeds the capability of the lubricant, resulting in ring coking and other issues. An iOLM would account for this, and I'd argue that Toyota is generally never on the forefront of innovation, but that's not really a valid excuse here, since GM has been using them for 20 bloody years, they are hardly bleeding-edge tech at this juncture.
 
that would be very true if only CAFE and the ecological mandates do not exist.
Currently all manufactures care mostly about saving a drop of fuel and jeopardizing reliability by pushing new questionable tech into new models. Otherwise hefty fines are issued by regulators.

Let's not forget recent examples failing Tundra's new turbo engines after moving away from NA V8 due to the same same chase to save some fuel. How Toyota allowed this untested unproved engine in mass production, is very well understood. They're caring about CAFE more than about returning customers.
The Tundra issue was a manufacturing issue. Debris was left in the engine. People who did the early oil change that everyone should do were smart.
 
The Toyota turbo V6 failures were brought about due to debris left in the engine following machining. This is a direct result of the failure to clean and prep the engines prior to assembly. This is a breakdown of the established norms that are always to be in place prior to engine assembly. This is a human failure, not an engineering or sales or marketing failure that is driven toward fuel economy

It’s my opinion that if these Tundras were built in Japan, this would not have been an issue. I hate to say it, but the quality of many vehicles built and United States and Mexico is far lesser than those built in Japan.

We have a 2008 FJ that was built in Japan as they all are. I hate to say it, but it’s been the best vehicle I’ve ever owned. I also hate to admit it was quite a step buying a Japanese produced vehicle for me. Long time Chevy, long time Ford owner.
Yes, the Tahara plant in Japan is legendary. They make the Lexus GX, LX among others, and the 4Runner and Land Cruiser. I'd take a 20 year old SUV made there over many new cars.
 
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Oil doesn't age in "miles", it's a poor metric, but it's simple and easy to track, which is why most cling to it. Engine hours or fuel burned are both better proxies for degradation.
What's your take on time as a variable? What if you're under engine hours, miles, and fuel burn, but the oil was changed 6 months ago? My manual (among others) recommends 6 months or 5000 miles, whichever comes first, for severe service.
 
What's your take on time as a variable? What if you're under engine hours, miles, and fuel burn, but the oil was changed 6 months ago? My manual (among others) recommends 6 months or 5000 miles, whichever comes first, for severe service.
My SRT recommends 6 months, last OCI was 16 lol. It has an iOLM, so I ignore the 6 month recommendation and just run out the OLM.
 
One must keep in mind that service intervals are driven by two things.

First and foremost, they are calculated to provide the absolute minimum servicing the vehicle needs to get it through the provided warranty. It’s kind of a ******** sales pitch that associates use to make you think you’re saving money.

Additionally, in recent years, the published extended service intervals are to satisfy the EPA and CAFE mandates allowing manufacturers to state that these vehicles are now designed to use less oils and lubricants. Using less oils and lubricants, at a longer interval, creates less waste.

A smart person will take whatever the manufacturer is stating and cut it in half or 1/3 if he or she desires to prolong the life of the vehicle to its fullest extent
💯💯
 
My SRT recommends 6 months, last OCI was 16 lol. It has an iOLM, so I ignore the 6 month recommendation and just run out the OLM.
So do you think there’s no reason for time based oil changes? I posted a thread about it soliciting opinions. People are divided on it.
 
So do you think there’s no reason for time based oil changes? I posted a thread about it soliciting opinions. People are divided on it.
I think OEM's use time as a factor to ensure that oil is getting changed, though 6 months seems nuts, but I believe GM limits it to one year. This is because moisture and fuel can both accumulate in oil and this isn't accounted for in the OLM algorithm.

If, like me, you are getting the vehicle up to temperature, but you don't drive it huge distances regularly, then that issue isn't present, as evidenced by my UOA's. Of course the OEM's can't expect that of the end user, so they do a CYA by mandating a time based interval, irrespective of mileage.

My engines are also port injected and don't meaningfully fuel dilute. If you have a DI mill that's dumping gas in the oil and the vehicle is short tripped a lot and not regularly getting up to operating temperature, getting that oil out of there at least ever 12 months is probably smart, if not sooner.
 
I think OEM's use time as a factor to ensure that oil is getting changed, though 6 months seems nuts, but I believe GM limits it to one year. This is because moisture and fuel can both accumulate in oil and this isn't accounted for in the OLM algorithm.

If, like me, you are getting the vehicle up to temperature, but you don't drive it huge distances regularly, then that issue isn't present, as evidenced by my UOA's. Of course the OEM's can't expect that of the end user, so they do a CYA by mandating a time based interval, irrespective of mileage.

My engines are also port injected and don't meaningfully fuel dilute. If you have a DI mill that's dumping gas in the oil and the vehicle is short tripped a lot and not regularly getting up to operating temperature, getting that oil out of there at least ever 12 months is probably smart, if not sooner.
I’m sorta on the fence regarding do I even care about improving oil consumption in the case of my 07 Fit because when I look at calculating hours on the oil; I’m around 30 HRs / month. Or 360 annually. Most of the driving is simply commuting. 20 miles interstate / 7 miles side roads with minimal stop and go each way; 40 minutes max.

It’s on its second interval of Amsoil SS now. The UOA on the first run last fall was at 12.5k miles; or approximately 210 Hours on the oil.
This run I’m going for 15k miles. And the thing is it may be more repeatable in part due to being able to top off that 1 Qt every 4k miles; thereby boosting TBN. Annual mileage is 18k. If the 15k comes back good, do I just shoot for the 1 year?

Interestingly, Amsoil Signature states 700 Hours maximum operation for both their Normal & Severe service recommendations. I wonder why the Hours are not reduced for severe service? Is it instead based on increased unburned fuel and dusty conditions so the hours don’t really matter as it becomes a passing of time/miles thing will happen before the hours are reached? I suppose I expected to see the hours cut down to maybe 500 for severe. 🤔

Of course, I digress…it’s still more expensive having to top off and the interval likely is fine on SS if it didn’t have any consumption given the usage in this case falls under Normal service conditions.
 
If you have an engine prone to piston ring stuck issues, or an engine this is very hard on the oil, then 4k OCI with full synthetic is similar to 3k OCI with conventional oil.

If you have an engine which isn't too hard on the oil, then 5k OCI with full synthetic should allow you to reach 300k miles with the vehicle.
5k miles / 6 month is my limit for an oil change.

I like buying cars from very old retired couples who never heard of BITOG and barely know what an oil or engine does.
They change oil every 3k miles, which I like.
Yep, I bought my 04 Expedition 5.4ls 2v that was elderly owned, oil changed every 3k at dealership and the engine was spotless inside. Nothing wrong with 3k oci at all. On the other hand my 05 Element had stuck rings and cam lobes were covered in heavy varnish by using cheap quick lube oil when the maintenance light came on, 7500 miles.
I do 3-5k (or every 6 months) oci's and will continue to. Like some mentioned it gets you under the vehicle to check for any problems.
 
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