Didn't mean to strike a nerve here. I know some of you have an overriding desire to be right all the time and that is fine. I will read the thread recommended by Thai. The unbiased opinion was tongue in cheek folks. Lighten up. I do know that I have changed oil in my 99 SR5 every 3k mi since new. It has 107k on it now. The old oil has been dark ever since about the 15K mi oil change. That dirt/carbon in suspension is not a lubricant. No science will tell me otherwise. Too many mechanics have said change it every 3-5k miles. I stand by my original claim that oil is cheap and rebuilds are expensive. In the 30+ cars I have owned over the years I never had to do a rebuild. I change the oil.
I did work for an oil company, and their studies did confirm the breakdown of additives at 2k miles. I would not expect their recommendations to be unbiased as they do sell oil. By the same token auto companies sell cars. If you need a new car b/c you did not maintain, they are happy to sell you a new one.
I apologize. I did not want to start this age old argument on this forum. Instead I will return to lurk mode and leave things to the pontiffs.
eace:
No sweat bluebullet, its not really about being smart or right, but realizing how far weve come and embracing new technologies. While long oil changes are getting more mainstream these days there was a time not too long ago you were thought insane for changing oil at 15K miles. Not unlike flying or going into space, thought impossible or suicidal at the time, after research, testing, and experience its a fairly mundane task at present. Warranty concerns aside.
A followup. I did read the thread Thai recommended and I have trouble concluding that my advice was bad. Seems opinions are all over the place.
A clarification. Some oil additives begin to breakdown at 2K mi. The keyword may be begin. The additives are still effective, just less so. I do not know when the breakdown is complete or even 50% complete. It also will vary for each type of additive.
I can see stretching the oil change interval to 5K mi. In fact I do that on my Duramax diesel rationalizing 2.5 gal of oil should last longer than 6 qt in my 4Runner. OTOH I change it at least every 200 mi in my KTM 4 strokes. Crankcase capacity is 1 L on one and 600ML on the other.
I would agree and go even further and say that the add pack
begins to breakdown within as little as 1K mi depending on the oil. But that breakdown is not linear, meaning it wont start at 10 and just go straight down to 0 in 5K miles. It will start at 10 then drop to 6 after 2K mi then by the time you reach 5K it will be at 4.
All things considered it would be quite foolhardy to throw in some syn oil and think you can make it 15K without changing it. That is why a used oil analysis is such a useful tool when determining how long to extend your oil changes by analyzing the condition of the oil after X miles. Im sure that Toyota in this case has done just that, in addition to tear downs and many other forensic analysis. The size of the sump has little to do with it as well, as Hondas have small sumps and are OE spec'd to go 7500 miles.
Something I find interesting is that the 3K/3mo oil change is "cheap insurance" in this country but we spend extra billions of dollars, generate excess waste, and waste way too much time. Thats hardly cheap, European cars have had OCI of 10K mi +, and rarely (if ever?) have oil related engine failures.
I was recently having this discussion with my friend who thinks Im nuts for going even 10K on oil, and I wanted to compare it to something that was easy to visualize and was a similar consumable item. Tires! What if the "American Tire Institute" or OEM recommended changing your tires every 15K miles? A tire with 15K miles on it is no better than a tire with 20K, and plenty of people measure their tires and go, hell up to 80K depending on the tire. You could say that you changed your tires every 15K mi for 100K mi and everytime you change them they are more worn down then when you installed them, but what did you really gain over the guy going 80K on 1 set of tires? So as long as you are aware of the condition of the tires (or the oil) you could use them until they were no longer safe (or offering protection).
Sorry for the long winded reply. I used to be firmly in the 3K/3mo camp and got sucked in over at BITOG and havent been the same since.
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