Oil Change

Tom & Ray,

I’m sure you must get the simplest of questions concerning oil changes and how often they should be done. However, I have yet to hear you discuss the same on air.

The question is: I have a new car ('09) that tells you the life of your oil. However, is there ever a limit to the maximum number of miles of when it should be changed anyways? For instance, my last oil change I went 10,300 miles and still had 3% life showing. Right now - today - I have went 6,700 miles since my last change and yet the life shows 51%. Thus, it appears I will or could surpass 13,400 miles before needing to change oil. Do I trust the reading and proceed.

Furthermore, at a family get together this topic became a heated issue. Some saying GM (and the others) want you to go longer so you ruin your engin so you have to buy a new car. Others were saying it’s simply the advacement of today’s engines and oils whereas allowing to go a lot further than the old 3,000 mile rule. I tend to believe that what the car is telling me is correct.


Read the owner’s manual. Some manuals recommend at least an annual oil change regardless of the oil minder reading.

If this were my car I’d change oil according to the computer recommendation, or once a year, whichever comes first.

No, GM does not want your engine to wear out faster. They tried that in the past and look where it got them.

The computer that monitors oil life measures LOTS of things, not just mileage and time. Trust the computer.

Tom & Ray don’t answer questions here. When you start a thread, you have the choice of posting it in 3 different forums. One of them is called “The Show” which addresses topics The Boyz use on The Show…

Your car has no clue about the true condition of the motor oil. What you are looking at is a computer program that is guessing about the condition of the oil. A more accurate method is to simply pull out the dip-stick and LOOK at the oil!! Once it starts looking dark tan in color, it’s time to change it…When it becomes non-transparent, black goo, it’s past time to change it…

I think that the oil life gauge is correct. We have a 2003 Olds with 94,000 miles and I’ve used the oil life gauge to tell me when to replace the oil. It doesn’t butrn oil, so it must work (for me, anyway). I must admit that I am skepticl of the oil change monitor on my Kid’s Cobalt. At this rate, the oil change monitor will reach zero at about 11,500 miles. I plan to tell her to change it at 70% (about 7500 miles).

“Some saying GM (and the others) want you to go longer so you ruin your engin so you have to buy a new car.”

That’s just plain silly. Any company that would do that will be out of business in a few years. No automobile company selling in the USA is that short-sighted. Here are a couple of questions for those cynical relatives:

  1. Was the JFK assasination part of a sinister plot?

  2. Were the NASA moon landings really hoaxes recorded on a movie set at Area 51?

A yes answer to either tells you what you need to know.

The computer tracks a number of things, not just miles. Different driving conditiopns can make a big difference. Prior to the computer system they had to recommend the based on worse case situations. Today with better oils, computer monitoring and better engine design we don’t need as many oil changes.

Having said that, if I had a new car with that system on it, I think I would not totally trust it yet. I would likely change it well before it said 3% life remaining.

When the car companies went to the 5,000 - 6,000 mile changes I was also unsure, but with the new oils and engines it has worked out well. Many people are still useing 3,000 mile changes but there does no seem to be flood of engine failures. I am now using the longer oil change time.

Not only do modern engines produce less external pollution, they produce much less internal pollution. Therefore there is less carbon, less gunk, less dirt, less of everything that depletes the oil. Heat and water condensation are issues that can deplete oil, but those who drive their cars a decent distance after start up have minimal condensation.

Personally I don’t own a car with the oil guage system. I tend to trust it and I don’t feel mfgs are looking to sell replacement motors for a big part of their profits. The bad publicity from pre-mature motor failures would be a larger concern for me if I was GM or Ford.

That said; I don’t think I’d run a car all the way to 3%. It is still your car and you decide when you want to change the oil. If I had one of these cars I’d change the oil at 20%. Fresh oil is better than old oil. The benefit of these guages is less used oil stressing the enviornment and I’m all for longer oil change intervals as long as the motors handle it. Sludging would be my biggest concern and that’s why I’d opt for changing at about 80% used up or 20% remaining reading of the guage.

When I say new car I mean it’s only 13 months old but yet I already have more than 32,500 miles on it. My first few changes were at or around 7,500. Since then I have used the monitor to tell me when to change my oil. When I had it changed at 10,300 it looked pretty good - I was surprised. The mechanic that was doing the change said he wouldn’t go more than 10,000 but yet the mechanic in the next bay say he would trust the life expectancy monitor.

wow, 10K and 13.5K on an oil change. I heard some company is converting waste cooking oil into a new car oil that can go 100K between changes. It’s new age stuff and will put all the oil manufacturers out of business. Also, the oil filter has a compartment that you can place some wings side by side for a quick snack.

personally, I change mine every 2-3K no matter what. What’s $15 for a change (assuming dino vs. synthetic)??? Now I know why I buy new cars and not used ones. You never know how it was maintained. Good luck with the 13K changes. Let us know if the car doesn’t burn oil when it clicks 150K or so (if it gets there).

If your driving habits involve a number of short hop trips and stop and go driving then changing the oil every 10k miles is not good. Changing it every 7500 may not even be good depending on the habits and environmental conditions.

Those oil life monitors do not and cannot detect moisture in the air, the amount of dirt, etc. and there is not an oil made that cannot be contaminated by these things.
I would also advise not listening to these conspiracy theory people who are telling you the car makers want you to ruin your engine by recommending longer oil change intervals. Jeez.

Do a net search about oil sludging problems and while some of those people will blame the engine, the car maker, or anything else on Earth for the problem it all boils down to one thing; not performing oil changes more regularly.

Oh GOD, Not ANOTHER oil change question!!! If you click on the “SEARCH” tab and search oil changes you will see that this topic is discussed at length almost daily here. You will find the answer to your question.


There is no conspiracy to get you to go so far that you ruin your engine and have to buy another car. No manufacturer wants to develop a reputation for vehicles that have to be replaced too soon. Brands become successful for developing exactly the opposite reputation, for making cars that last well beyond expectations.

Others have discussed how much better engines and oils are as a reason why they can far longer between changes. To that I can only add my personal philosophy, that oil cannot be too fresh, only too old. I personally would not go beyond 5,000 miles between changes, and definitely would lose sleep nights if my oil had 10,000 miles on it.

Two of your oil’s jobs are to keep the insides of the engine clean and to remove heat from the cylinder walls. These are tough jobs. The fresher the oil, the better it can do them. And it’s primary task, keeping the interfacing parts seperated by a nice pressurized fluid barrier that’s as slippery as can be, is also better done if it’s not carrying a bunch of microscopic particulates and combustion byproducts.

Oil is cheap. Engines are expensive. I’d rather extend the life of my engine than the life of my oil.

I prefer oil change questions over “hypermiling” questions. As oil monitoring becoms more sophisticated these questions will keep recurring. I would like to have actual oil acidity measured, it’s a very good indicator of remaining life. GM pioneered this some years back, but instead chose the computer simulation route.

To answer your question about driving patterns, I am on the highway/expressway A LOT. And at night the car is in a heated dry garage about 98% of time. Again, when I changed it at 10,000 it was quite clean and not thick or sludgy at all.

There’s nothing saying I will go to the 13,000 mark but at the pace I am on that’s what it would be if I went to 5-10% - and thus the reason for asking how far is too far.

When I had it changed at 10,300 it looked pretty good - I was surprised. The mechanic that was doing the change said he wouldn’t go more than 10,000 but yet the mechanic in the next bay say he would trust the life expectancy monitor.

I am not suprised. We all tend to form opinions based on our experience. Until you try the longer intervals you will not change you mind.

What you will find is people are all over the place on oils to use and how often to change. The whole point is to consider the various options people choose, and the reasons they give, and make up your own mind. Just make sure you know why you are making that decision.

This is important because no matter what you decide, there will be people who disagree with you, and will not hesitate to tell you that you are wrong, so know why you are doing it. Was it Davy Crockett who allegedly said, “Be sure you are right, then go ahead?” If you have a good reason for what you do, tell them, as politely as you can, to go pound sand, heh, heh.

In no case change your oil less often than the manufacturer’s recommendation says. If it says obey the monitor, well, just don’t go past it. If it says every 7,500 do not in any circumstances go past that mark. Etc.

I am not one who believes manufacturer’s deliberately encourage excess mileage on oil to destroy the car. My problem is they don’t tell us what mileage on the motor their recommendation is aimed at. (You can be sure it has a motor mileage goal.) Is it 450,000 or 250,000 or 150,000 or 100,000? Since I don’t know, I cannot accept the manufacturer’s recommendation, because I prefer 250,000 or more.

I have been on this board for years, and have followed the constant disagreements on oil changes. So, this fall deciding to find out for once and for all what is correct, I sent a sample to Blackstone Labs, after deliberately letting it go 8800 miles. (2002 Sienna with 158,000 miles and mostly highway driving.)

I expected a report on the oil condition and no more. To my surprise, while it did report my oil was still good, it also gives you information on the motor. Depending upon the chemicals in the oil, you can tell if engine wear is normal or excessive; if there is blow-by; and a number of other things. It is like a look inside your motor.

My oil had a tbn of 2, new is allegedly 10 to 12, and tbn is the stuff that neutralizes acid, so it would have been good to 10,000 miles. I have decided to change it at 7500 miles or so, which is a comfortable margin. As long as my driving pattern does not change, I will NOT be changing it at 3,000 or 5,000 miles any more. I consider that decision, under my view of personal liberty, to be a valid one if someone wants to do that, but for mostly highway driving and synthetic oil, I do think good oil is being tossed. (I am saying, though, that is their right to make that decision, and for sure will not hurt the motor, unless someone strips out the drain plug, heh, heh.)

That is correct for my car and my driving patterns, and cannot be assumed to be the same for a different car or driving pattern. Others would need to have their oil tested for their own driving pattern, and I think in the Snow Belt, that would include once in the summer and once in the winter when things change drastically.

Even with Fedex shipping, to avoid dealing with people who work under the umbrella of the Federal Government (post office) it came to less than $40, and it was worth it to me to find out what the truth is.

Note that I choose to use Mobil-1 EP synthetic, because my car is one which allegedly had risk of sludging. I have contemplated running dinosaur oil for 5,000 and testing it, but decided not to because of the sludging risk. It isn’t worth it, and the extra cost of Mobil-1 when I change it myself (Wal-mart oil) isn’t worth the risk.

There is a gentleman here who has it tested every change. I like others thought that was excessive until I learned it actually reports on engine condition. I still won’t do it every change, but will have it tested, oh, maybe every 25,000 to 35,000 miles to keep track of the motor condition.

So, if you really want to know, pay for a sample or two, then you will know with 100% certainty what you should be doing. My personal hunch is 60 to 75% of mileage recommended by your monitor will be plenty of slack, but that is only a hunch. Find out for yourself.

Change the oil when the monitor says 50% and call it a day.

You might be referring to me for testing my oil. I had it done several times on a Caprice V8 to determine the amount of contamination after 3000 miles of driving. It turned out that I only had 60 parts per million of wear metals, and no real change in viscosity, Total Acid/Base Number and no glycol, water or gasoline contamination.

This told me that:

  1. I had no internal leaks from the cooling system

  2. The oil itself had not deteriorated (no viscosity change), so no overheating and “coking”.

  3. Wear metals were normal

  4. No fuel contamination, so the rings were good and I was not running a rich mixture.

  5. I could stretch the drain interval, since EXXON uses 200 parts per million of wear metals as the “condemning point” of the oil.

The conclusion I reached was that, keeping the same driving pattern (mixed city/highway, plugging in the car in cold weather), I could easily stretch the oil interval to 6000 miles and still be safe.

I like your suggestion.

As others have stated, opinions vary on this subject, and yours is an excellent compromise that ensures the engine is protected, satisfys those that prefer early oil changes as well as those that subscribe to going with the oil change monitoring system, and requires no understanding of the technical arguments we all use to justify our biases.

With your permission, I’ll steal your suggestion for future threads.

That sounds like a good compromise to me too.

yours is an excellent compromise

Even a broken clock is right twice a day.