Synthetic oil change intervals

Well said, Wha Who. The people who claim the most expertise on synthetic oils almost always admit they have never used it. I am going to copy and paste a posting I just made the other day on Old Wrench on this topic. Let me know if pasting a posting I made myself elsewhere has some sort of Netiquette rules, but if I thought so, I wouldn’t do it. And, yes, I am well aware there will be someone who says labs don’t know what they are doing, hee, hee.

On automobile forums, people are all over the place on when to change oil, with personal preferences being a major factor in the decision. However, too many people push their personal preferences as if they were on a stone tablet carried down from the mountain top, which can be really confusing when there are different personal preferences. Not to mention unpleasant at times when someone tries to force his opinion on others.

The most common personal preference seems to be oil and filter change every 3,000 miles. I have no problem with this decision, even if it could be shown to be unnecessary. Thirty dollars, 30 times, in 100,000 miles is peanuts compared to cost of a car or new motor. If someone feels better doing that, they sure need not explain to anyone. In fact, if a person has no specific reason when to change oil, but believes it need to be done more than factory recommendation, I think 3,000 miles for average drivers with traditional oil is probably a good idea.

Some people have reported similar cars in Europe have very long factory recommendations on oil change numbers, but no one seems to know why, unless it is a desire to reduce waste oil.

I am not exactly an average driver. I sometimes leave McAllen and drive thousands of miles before returning, and do not feel compelled to stop on the highway to change my oil at 3,000 miles as I would have in 1965. Oh, wait a minute, it would have been every 1,000 back then, right?

Also, over the years there have been some strong, but at times also wild, opinions stated on oil. One of the wildest was a person in the last week or two on CT who suggested anyone who believed synthetic oil had any advantages was experiencing the placebo effect. Blechhh!!!

So, finally, earlier this year, I decided to run my oil a bit longer than usual and have it tested to settle the matter once and for all FOR MY DRIVING PATTERNS. I didn’t realize at the time all the information one gets in the test. I thought I would just find out if the oil was still usable. (It was.)

My driving, mileage wise, is mostly highway, but I spend some months a year here in Mexico, in a dusty quarry town, and take a number of short trips a week, plus several hours to the city for shopping each month.

I returned to the States in early October, and changed out my Mobil-1 EP, and Toyota filter, which had 8800 miles on them, and the motor had around 158,000 on it. I sent a sample to Blackstones. I do not intend to endorse them over any other lab, assuming others exist. It was simply the one I read about. I think by the time I paid (Fed Ex or UPS? I forget, though I know where the drop-off place is) shipping, to avoid dealing with government employees, it came to the thirties.

I expected to post the report but it says Copyright all over it. I can see that. If I start summarizing or explaining it, I may not do it accurately.

To my surprise the oil test is a good report on engine condition and wear. They check a variety of “wear contaminations”, compares them to their running average of test customers, and explains what that contamination tells you about your motor. If your lead contamination is high, that implies, for example, more bearing wear. There is one which they say may indicate worn rings with blow-by. Copper might be wear on another part of the motor. There are others as well. Water in the oil is measured. Gasoline. Antifreeze contamination will be reported. Silicon indicates the amount of dust which gets past the air filter, and mine agreed with use in a dusty quarry town, heh, heh.

The average mileage on a Blackstone oil test is around 4800 miles, as compared to my 8800 miles. Some of my wear contaminations were higher than average, but not in proportion to the fact it had nearly twice the miles on it.

The ‘tbn’ whatever that is, which they say correlates to remaining additives, was around 2, and new runs perhaps 10 or so. So, at 8800 miles, I feel (my own ignorant opinion, or personal preference if you wish) I would not want to have used that oil more than 10,000 miles or so.

Blackstone did not exactly say the oil was still good. What they said was they recommended testing it again after another 7,000 miles. I may be wrong, but I cannot imagine their lawyers telling them to recommend putting another 7,000 miles on bad oil.

At the same time, I also don’t feel compelled to change my Mobil-1 EP oil under current warm weather driving conditions before perhaps 7,500 miles minimum.

I had thought to do this testing only once. But, now that I have learned it supplies a lot of information on motor condition, I will probably do it every year or two. It’s just too much information for too small a price.

I am not going to ‘recommend’ others have their oil tested. I will say that the information it supplies on the condition of the motor makes it a rational act if someone wants to do it. The thing to remember is each car and its maintenance and its uses are different, so one cannot use my test results to make his own decision on oil changes.

Most comments here have referred to the oil and not to the marriage.

You’ve been married how long, and you are trying to change your wife’s chosen oil change pattern???

The Cartalk brothers often refer to this issue in their answers in the columns. Even if you are technically right, it makes no sense to antagonize your new wife over something trivial like oil changes. If she changed it every 30,000 miles that might make sense, but to antagonize her over changing it too often, seems to be an irrational act in a nation with a 50% divorce rate. Speaking as a man who supplied no-fee counseling to more than 1,600 divorced men. You can pay for an awful lot of oil changes cheaper than lawyer fees; property settlement; alimony; child support; etc.

That truck is ten years old, and it sounds like she has kept it running very well. A $30 oil change 30 times in 100,000 miles is not worth interfering with her.

I think you may be just trying to justify running a new car down to 3% but do what you want. For $24 I can get the oil and filter changed at the dealer while I read a book. You run it down to 3% and I run it down to 50% so you’ll just have less reading time.

Now if you think engineers (and competent ones) make all of the decisions that make it into the owner’s manual, I think you are forgeting the marketing departments. There has been a strong push from the marketing departments to extend maintenance periods and increase fuel economies at our expense. Thus 7500 mile oil changes and 5w20 oil. Some of us choose to be more conservative in our maintenance while the jury is out on the wisdom of the marketing departments. So do what you want.

Amen brother. Nothing like cutting through all the garbage to the real issue. Now if you’d like to help on the narrow snow tire controversy . . .

Well I use synthetic oil change at 10,000 miles, my 85 Toyota had 235,000 miles when I sold it and it might have used a quart by the time it was due for a change. My Suburban had 79,000 and used no oil when I sold it, my current Toyota Sienna has 50,000 and doesn’t use a drop between changes. By the way I towed a small boat with all of these vehicles nearly every weekend 140 miles round trip.

Mr. Bing,

Coming from an engineering background but not in the auto industry, I clearly see your point as I have had much contact with marketing people but I do not agree that marketing people will have the final decision on oil change life if it compromises engine life in a strongly competitive environment.

Marketing will express their desires to engineering people and will leave it to engineering people to solve a need for a competitive advantage which in this case is longer oil change intervals. I do not believe for a second that marketing people would be permitted by upper management to override engineering people when engine life is at stake and maintaining the reputation of the brand is vital.

I am not trying to justify anything because I do not need to justify anything. It is my car; it is my motor; it is my money. I have explained why I have made my decision, it is based on lab testing, not marketing reasons nor manufacturer recommendations for average driving conditions, and I need apologize to no one for making a different decision than they do.

My tbn which is the amount of acid-neutralizing additive remaining was 2 and new is allegedly 10 or 11, so this is closer to 20% than 3.

In my case I am responding to actual oil testing, BASED ON MY PERSONAL CAR AND MY PERSONAL DRIVING PATTERN, rather than making a personal guess at when to change it which is what most folks do. I have no criticism at all of those who merely respond with a guess, since they are taking good care of their car, thus it is a valid choice. I have said so many times. You gotta’ be happy with what you are doing, no matter how you arrive at your decision.

My decision has been made on lab test of my car, not actuarial calculations made for a large population, which is what manufacturer’s recommendations probably are, as you say modified by marketing interests, also intended for large populations.

Exactly. Pretty much what I would expect based on my oil test results. Thanks for the information.

I do not wish to actually criticize anyone’s personal decision on when to change oil, since we see too much of that on this URL, and much better to change too often than not often enough. But, I do think a lot more oil is changed than need be, in part because people lack actual data on oil condition. Not that it matters; let me repeat. Never criticize anyone for changing oil too much. The extra costs are nothing compared to vehicle costs.

Exxon-Mobil guarantees Mobil-1 Extended Performance oil for 15,000 miles. They use extra additives to extend the lifetime. They also sell Mobil Clean 5000, a conventional oil, and Mobil Clean 7500, a synthetic/conventional blend. They are guaranteed for the advertised number of miles in their names. I use conventional oil and change at about 7000 miles, but my driving is almost exclusively on a highway.

Mr. irlandes,

There are environmental costs too. That is being burned into my Luddite brain. I am not inclined to always take that seriously unless it is easy until I feel impending doom in an environmental sense which has not happened. Longer oil changes are easy. Your personal feelings about vehicle costs may be more significant than you believe now.

I am aware too of wondering about the significance of the environmental cost of wearing out a car early compared to changing oil early to preserve the engine. I can say that I have not traded a car since 1966 because of a worn out engine. All were due to because we could except for two with rusted out bodies.

jt; thanks for the additional info. Without additional additives you simply can’t stretch the drain interval.

You seem to have found the right interval fo your type of driving.