Last a few months wasn't too happy with car performances. Engine sputtering and transmission acting confused what speed when. Well, I said whatsoever car is 294k and probably do not get better than it. Past Sunday I did figure out that rear passenger caliper is sticking and pad is gone. Characteristic worn pad noise. It turns out both rear calipers were frozen and one brake bracket. But only rear passenger was dragging at rotor. Replace it and it was less sputtering and transmission worked fine. 6 days later, Saturday replaced oil and filter. I'm adding oil once per month because is leaking somewhere. I'm suspecting it is from drain plug but it is happening only when I drive so I'm not sure. Will see with new plug. So, because I use synthetic I didn't replace oil for 30K. I know for sure 25k work with synthetic as I follow it for 15 years at all my cars. Here I went 30k because I add quart once per month. Problem was I didn't replace filter to for 30k and it is rated only for 20K. Well after replacing oil and filter and before it solving sticking brake pad car is again driving like a champ. Both engine and tranny are flawless. Just head up.

 

I think that even newer vehicles that use synthetic oils will have OBD that tell an owner that the oil needs to be changed based on a number of factors. I doubt any new vehicle would last that many miles without needing an oil change prior to 30K miles; so it would be unrealistic to expect that from a 20 year old engine.

With regard to your oil leak, I am guessing (based on the pics from your other post) that your leak is coming from that oring just above the rear main seal; which (I've found out through experience) is a very common thing with our engines.

https://acurazine.com/forums/second-...6-swap-983133/

 

3000 miles or one year. That's my engine oil change schedule. I guess it's just shows how much punishment these j-series can take. Since we've all seen some of your very competent work here on the forums, I'm kind of curious as to your thoughts behind waiting that long between changes.
I agree about the oil leak. My TL is part of the leaky o-ring club. Took a while to be sure because of the way the oil gravitates downwards around pan. Definitely wouldn't have figured out it was that o-ring without the info on these forums.

 

Sounds like a personal problem.

I have that same leak though, I’ll eventually replace that o-ring if/when anything transmission wise acts up or it gets worse. For now I just use an oil mat when parked in my garage.

 

As you would guess I did investigate and wrote it in my Microsoft word file. File is 30 pages long. For one I use Mobil extended performance fully synthetic that is good for 20K. At Acura I replace oil every year once and it is somewhere from 20-25k unless leak show up like now so I did 1,5 years but obviously oil filter come into play. At my F250 LD once in 3 years and it is 18K around. It all come after a lot reading. Obviously cannot copy paste that folder here. Of course I use filters that are good for 20k. I'm planning to do oil testing and will do for Acura next year after 20k.
A few comments from there
"The once a year oil change is correct for old dino based oils, but if you use a modern full synthetic it won't degrade when not in use for far longer. Modern synthetic oils do not absord moisture or break down in the same way as the older engine oils and Blackstones labs just had an oil sample from a Nissan truck returned that was not changed for 15 years and it showed no signs of old age in terms of water content or viscosity changes, although it did contain high levels of wear metals due to the 165,000 miles it had done.
Not running the engine is the real issue, because if you don't run an engine at least every month it can result in corrosion of the injector tips and even the cylinder rings. There will also be an increase in initial wear factors when the engine is next started, unless it is turned over first to lubricate the cylinders etc."

"When the additives wear out in a synthetic oil it still has the same viscosity. It will not thin as a mineral oil. The fear that some say Porsche has that oils thin when the VII runs out is not applicable to these synthetic oils. These oils will always have the correct thickness when hot and will still be too thick at startup as with all oils of all types, regardless of the API / SAE viscosity rating.
Synthetic oils are a whole different story. There is no VI improver added so there is nothing to wear out. The actual oil molecules never wear out. You could almost use the same oil forever. The problem is that there are other additives and they do get used up. I suppose if there was a good way to keep oil clean you could just add a can of additives every 6 months and just change the filter, never changing the oil." This guy was chemical engineer and spent all life in car oil making industry.

"LDB (this is that guy doctor in oil industry)
The VI improver issue can’t be countered by additives since that is itself an additive. Its problem is that it isn’t all that stable, and as it degrades, you can lose viscosity. The biggest advantage to full synthetic oil is that you get a 25 spread between W and normal number (such as 5W30) without VI improver. But wide spread full synthetics like 0W40, or pretty much any dino oil needs VI improver. That’s why most extended life oils are full synthetics with no more than 25 spread. Note that I retired 11 years ago and doubtlessly, VI improvers are getting better with time. But I sure wouldn’t go past 10,000 miles in my own car on any full synthetic with more than a 25 spread. And while dino oils are fine out to 10,000 miles, since they use VI improver at all spreads, I wouldn’t go further than that on any of them (except for the few, low volume, niche oils that are made with the few dribbles of real Pennsylvania grade crude that are still around, but that's a longer topic that I've covered in other posts)."

LDB

"LDB
See post #10. You might think the answer is too trivial, but it’s not. Assuming decent rings, which then means no excessive sludge, and further assuming no VI improver is needed, which in turn means little or no shear degradation of viscosity, there’s not much to “wear out” in a full synthetic. All that’s needed to extend the oil change interval are a few band aids. As noted in post #10, the biggest one is pH buffer. You can’t go to zero blowby, which means you can’t go to zero carboxylic acids, which means if you don’t want to corrode your engine away you must have a considerably higher loading of pH buffer. Besides that, there’s probably a bit higher loading of anti-oxidant and a few other minor tweaks, but if you said it’s the 10,000 mile stuff with more pH buffer, you’d be pretty close. And by the way, the comments don’t just apply to Mobil1. They don't have the market cornered on extended interval oil. All brands of extended oil change interval oil must address the pH issue.
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You are correct. Frequent oil changes are not cheap insurance, they are wastes of money and resources. As you point out, in comparison to the “3000 mile days”, the oil itself is vastly better today, but there are also fuel and emissions system changes that help with oil life by making the environment in the engine’s crankcase vastly friendlier to oil.

Remember that due to piston blowby, the environment in the crankcase would be pure exhaust gas if it weren’t for PCV system, which draws outside air into the crankcase. With PCV, depending of course on the condition of your rings, the crankcase environment is usually more air than exhaust gas. It should be intuitively obvious that exhaust gas is more corrosive and has greater potential for sludge formation than air. And the diluted amount of exhaust gas that does remain in the crankcase is less harmful to the oil due to fuel changes (essentially zero sulfur and zero lead). Bottom line is that while the 3 month, 3000 mile rule made perfect sense in 1960 with 1960 oil additive technology, no synthetics, before PCV, and with both sulfur and lead in gas, it’s wasteful overkill sixty years later.

While it probably won't change many minds among the frequent oil changers, I know oil backward and forward, and change oil in my own cars at 10,000 miles or 18 months, whichever comes first. If I'm still in warranty I stick with 12 months to stay out of warranty risk, but other than warranty there's certainly nothing magic about 12 months. For those who don't drive very many miles, if out of warranty related risk, you could probably go beyond 12 months too. Before saying how much further, I'd ask why the low mileage. If it's because you don't drive the car often, but when you do drive it, you usually drive far enough to get the oil hot (meaning oil above 170, coolant temp doesn't matter), I wouldn't be afraid of 24 months. But if due to most of your trips being short, where the oil often doesn't get above 170, I'd say stick with 12 months. Reason for the difference is that when cold, some of the water vapor from piston blowby condenses to liquid water. Liquid water is a serious enemy of oil due to carboxylic acid formation, so if you don't get the oil hot enough to evaporate it, your oil life suffers. And due to that liquid water problem, if you are in the prior group of low mileage because it's not driven very often, don't make the mistake of starting it now and then in the garage to "coat the cylinders with oil". Once you start the engine, minimize the number of times you turn it off before the oil reaches 170.
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Yes, I'm a chemical engineer who spent a career at a major oil company, retiring in 2011. I stayed on the technical side rather than crossing over into management, and if this makes any sense, ended up as a technical specialist in being a refinery generalist. That means if you considered any individual area of the refining business, you?d find experts who knew more about that area than I did, but I knew more about the technical aspects of refining taken as a whole.
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"Today’s lowest grade motor oil now has sufficient additives for 8,000–10,000 miles; however, standard filters clog in about 5,000 miles, making an oil change necessary. The report stated that, in some cases, major automobile manufacturers have enough experience with onboard diagnostic systems to use 10,000–12,000 mile oil changes. This more than doubles the current U.S. average oil change interval, which is approximately 4,500 miles. Adopting this new oil change interval would reduce waste oil generation from the automobile sector by half. The report showed that oil change intervals of nearly 20,000 miles can be achieved using fully synthetic oils. Heavy-duty vehicles were shown to achieve oil change intervals of 60,000 miles and more with HE filters." (I use sharply filters rated for 20k at all my cars)