The oil change recommendations in the Owner’s manual are an attempt to cover a wide variety of situations with as simple of instructions as possible. To cover every scenario would take reams of pages and few would even bother reading. An oil test like the one posted is definitive for that person’s use case. I would trust that over any other recommendation based on general conditions or assumptions…
Eh, the car is out of warranty, do what ever you like.
Thanks for good advice. I cannot edit it so I have removed the link.
I know it seems counterintuitive but here’s why I claim that this time interval guidance cannot be intended for low mileage drivers.
The time interval for oil changes is the same as for the mileage interval maintenance. If I seldom drive the vehicle, I can reach the 30,000 mile maintenance level in two years with less than 5,000 miles on it. By then, according to the manual, I will have had 6 oil/filter changes and be due for extensive engine and mechanical inspections, lubrications and replacements–some of which I will have had earlier as each 4 month time interval passes. This does not make sense for a car with so few miles on it. It is usage that creates wear and tear and the need for adherence to the maintenance schedule. Oil is not like milk. It doesn’t curdle while in an unused vehicle.
So why mention a time interval at all? Good question. The people making these cars are engineers, MBAs, and generally pretty smart people. There must be a reason for it that makes sense, unlike the problem I have outlined for low mileage drivers. Here it is: as many persons in this Cartalk Community have pointed out, driving a vehicle extensively without changing the oil is likely to be very destructive to it. If in warranty, it may void coverage. So putting a time interval into the maintenance schedule is a way of emphasizing the importance of timely maintenance by reminding owners of how frequently they should be planning to service their vehicles. In effect, it says “Mark your calendars every four months” for needed vehicle maintenance. If your driving level is well short of the projected activity level, no harm done. Just wait until you get to the recommended mileage level. But including a projected time interval could be very important for high mileage drivers who don’t monitor their odometers or recall the mileage interval guidance.
In short, the time interval does not make sense for low mileage drivers, especially when the maintenance schedule does not distinguish between oil/filter changes and other maintenance services. It makes a lot of sense for high mileage drivers who do not pay attention to their odometer but do keep an eye on their calendar.
So the time interval is there only for high mileage drivers who ignore the odometer.
I guess self delusion and conformation bias of wanting to confirm what you want to believe can convince some people of anything.
I think this is the strongest example I have ever seen.
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One can only hope James does not cause anyone else to think like he does.
If he doesn’t use better logic in court, I hope he avoids trials.
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Hi Volvo_V70:
I’m puzzled by that reply.
James wanted to see how much the manufacture’s “one-size-fits-all” oil change recommendation fit his specific situation. He asked here and got answers all over the map. So he paid for an oil analysis to get factual information on the state of his oil.
Is there something flawed with that thought process?
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The only flaw was insisting that the time element in the owners manual did not pertain to low mileage drivers when low mileage drivers are the only ones it can pertain to.
The fact that oil analysis shows that he is not hurting his engine proves only that either Toyota builds great engines or there is a large safety factor in the recommendations.
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Sigh. Despite multiple, repeated explanations of the problem with the four-month time interval in the owner’s manual, I’m going to waste a few more minutes and try again. My owner’s manual projects driving 1,250 miles per month. This adds up to 5,000 miles, the mileage interval for service. Surely it is obvious that this is not a coincidence. But what if the owner puts more miles on the car than 1,250 per month? Then the mileage standard would kick in and the owner should have the maintenance service earlier than four months. Mileage indicates actual usage of the engine and other moving parts in the vehicle. Getting all of the scheduled maintenance services, including oil/filter change, is appropriate at that time. Even if the owner is following the four-month schedule, it probably won’t matter unless he is driving back and forth across the country.
But what if the mileage driven is less? In that case, the actual usage of the vehicle is less than projected and wear and tear will be less, too. What if it is substantially less to the point that only 5,000 miles have been put on the car in the first two years? According to the time interval alone, this vehicle should be receiving the 30,000 mile maintenance at that point and have had FIVE oil/filter changes already. The vehicle will receive checks, lubrications, replacements and new parts according to all of the time interval maintenance services that you dutifully brought your vehicle back to the dealer to receive despite not driving nearly enough to need most of them. If this makes sense to you, go for it.
Everyone in this community understands that running worn out oil through a vehicle’s engine is a recipe for early engine destruction. The manufacturers know that, too. They want to build good cars that have excellent reputations and repeat buyers. That’s how they prosper. But a good vehicle with no problems and no repair requirements might lead some owners to defer maintenance since everything seems to be ok. Putting a time interval in the maintenance schedule along with the mileage schedule is a way of emphasizing the need to have scheduled maintenance services. Better to do it too often than not often enough. If the owner does not have enough common sense to realize that operation of the vehicle is well below the expected level–and that, therefore, some services may not be needed as often–well, still better to overdo than underdo and the dealer gets extra service business. PLUS, the time interval is a reminder to owners who don’t watch their odometers. I assume that doesn’t apply to anyone interested enough in cars to join CarTalk Community but it certainly applies to some drivers in the general populace.
I have always followed the mileage schedule or an annual visit to the service department for the mileage maintenance services. In the past, these two generally coincided. But now that I am older and further confined by the COVID-19 pandemic, I am not driving anywhere near 5,000 miles per year. So I asked this community what concerns that might raise for my oil replacement. I am sorry to note that most of the replies were useless and many of them downright rude and insulting. A few wandered into the “stupid” lane.
Here’s a parting clue for how to participate in any general forum. Be polite and respectful. If you don’t understand something, acknowledge it, disagree, present your objections based on your own analysis and then move on. Agree to disagree. Attacking the proponent of a different point of view is poison for dialogue and a beneficial exchange of views. Volvo_V70 was snarky and insulting from his first comment and only got worse. I don’t know why this community tolerates a member with so much animus and so little to contribute.
As for me, this community is not one to which I will return. I did get the guidance I needed, thanks to JoeMario, Circuitsmith, and Wolyrobb. But the unwillingness and apparent inability of some of you to engage in a polite discussion and a courteous acknowledgment of a point of view you might not have considered before makes this forum a huge waste of time for someone (talking about me now) who doesn’t take everything at face value.
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Thank You.
Just being polite for James decision.
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Sorry you feel such troubles. I do oil changes spring and fall regardless of mileage. Don’t mind the posts as it is an open possibility in any board. Better too often than not often enough, my philosophy.
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“JamesCarney, post:91, topic:163296”]
As for me, this community is not one to which I will return
No great loss of some one who know’s he is the only one right and every one else is wrong.
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This is where your logic falls apart because you haven’t factored in degradation of the oil from short trips. Lower usage often means not getting engine warm or lots of short trips. In those cases, blowby is higher and water condenses but doesn’t burn off. This creates acidic oil and that erodes everything, especially bearings. Now low mileage could also be one or two long trips and that is less impactful. But the manufacturer cannot cover every scenario and so they lean toward worst case.
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Out of warranty for 12 years, do whatever you want.
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Engineers wrote it so the math works out. Not a coincidence but not a plot either. Those same engineers that wrote it also had it reviewed by a team of lawyers whose task is to make sure that no one will sue the car maker if the service is followed to a T and the engine still fails under the warranty period and much longer. This point is completely ignored in your argument.
An incorrect assumption of the maintenance based on the time. The dealer has records of mileage and as such will not just do the tasks listed in the 6 month or 12 month list that do not meet the mileage targets such as air filters and cabin filters. They will, of course, do or not do exactly what you ask them to do and are willing to pay them to do. They will not do anything more. Your records, your choice.
Really? Is this your first day on the internet?
So you got what you came for and changed no one’s mind to your position and now you are leaving. Sorry to see you go as this provided loads of entertainment for those of us who answered your question over and over again with the same answer.
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