When Should You Change Your Oil?

thecardoc3

Mr_Shiftright said:

One reason I do not change my own oil anymore, is that I want the car in the shop and on the lift, and carefully examined every 5K.

When oil changes were recommended at shorter intervals than they are today that was easy to accomplish. Now that's just about a third to two-thirds of a normal service interval. (most cars about half)

Mr_Shiftright said:

As for bad repair shops and shyster oil change operations, hopefully as cars become more and more complex, and consumers become better informed, these bad apples will be self-cancelling.

The operative phrase there is "and consumers become better informed". As it stands right now they are exposed to more nonsense than they are legitimate information and most of the nonsense is covered in sweet price oriented icing.

Mr_Shiftright

There's a lot of good information out there. It's not that they are being grossly misinformed, it's that they don't bother to look for information.

thecardoc3

What's the difference between misinformed and grossly misinformed?

Under which of those two categories should the following articles be placed?
http://www.edmunds.com/car-care/stop-changing-your-oil.html
http://www.edmunds.com/car-care/do-i-have-to-use-the-manufacturers-oil.html

How many times in the last five years did Steve make the attempt to confuse the issue of the difference between specification and brand? How many others did the same thing which served to delay not only a consumers comprehension of the specification but also its implementation?

Mr_Shiftright

So you're saying that changing the oil every 3,000 miles is good advice?

As for reading articles about oil specs, my eyes close over after the first paragraph. I read the owner's manual and I do what it tells me. How hard is this?

thecardoc3

Mr_Shiftright said:

So you're saying that changing the oil every 3,000 miles is good advice?

You already know the answer to that based on inputs to dozens of threads. The real question is what are you trying to dodge with such a misdirection. BTW. My escape is at 43% oil life at just over 5000 miles since the last change. Even with all the highway miles that I drive seems I'll never quite get to run it to 10,000 miles between changes as far as the monitor is concerned.

Mr_Shiftright said:

As for reading articles about oil specs, my eyes close over after the first paragraph. I read the owner's manual and I do what it tells me. How hard is this?

Apparently too difficult for 99.9% of the population, but that's just a guess.

Mr_Shiftright

It's not a misdirection at all. You pointed to an Edmunds article that was about not having to change your oil every 3,000 miles, and you labeled it as "misinformation". So what's that about?

And yeah, I know, lots of people don't read their owner's manuals. Don't ask me. I don't know why.

thecardoc3

Have you read (re-read) that article, and especially the comments? There is a word for taking a fact, which in this case is that cars serviced correctly can go longer (in some cases much longer) than that 3000 mile interval and using it to push inaccurate and misleading information.

From there, what about the other article?

If the issues with those (and other) articles were corrected, could the authors, publishers of the original ones open themselves up to liability if following the incorrect advice in them caused a consumer to suffer a loss?

thecardoc3

This is what an engine oil discussion looks like when everyone involved is convinced that they know all about the subject, when they have no formal training at all. http://forums.edmunds.com/discussion/12154/toyota/corolla/toyota-corolla-0w-20-oil-whats-this-about/p1

stever

Thought sure that was going to be a link to that oil guy's place (Bob).

Either that or the Chevron Tribologist Working Group.

Have you plotted your viscosity data and made your ASTM D341 graph today?

Try an automotive lubricant engineering forum - those folks are experts and are in complete agreement about oil and change intervals.

Mr_Shiftright

thecardoc3 said:

Have you read (re-read) that article, and especially the comments? There is a word for taking a fact, which in this case is that cars serviced correctly can go longer (in some cases much longer) than that 3000 mile interval and using it to push inaccurate and misleading information.

From there, what about the other article?

If the issues with those (and other) articles were corrected, could the authors, publishers of the original ones open themselves up to liability if following the incorrect advice in them caused a consumer to suffer a loss?

It's up to the consumer to determine the correct maintenance for their cars. If people dispensing advice were held liable for their advice, then every financial advisor on TV would be in jail by now, to say nothing of Dr. Oz. and Oprah.

thecardoc3

Mr_Shiftright said:

It's up to the consumer to determine the correct maintenance for their cars. If people dispensing advice were held liable for their advice, then every financial advisor on TV would be in jail by now, to say nothing of Dr. Oz. and Oprah.

So how exactly does the consumer know how do that when they have been fed information as tainted as what can be easily found? Lets take on the myth about oil getting dark. Here is what my oil looked like this weekend when it was due to be changed again.



The mileage at the previous service was 134.4K, this change was at 142.8K for 8400 miles and that was down to 6% oil life.

For reference here is what the oil looked like after changing and running for a couple minutes.



While there is a difference it is a very small difference as compared to what most appear to assume. The new oil will take some 6000 miles to even begin to darken beyond what you see on the dipstick, then it will start to change pretty quick. It is at that point that the scent of the oil also begins to take on a burned caste, which is again in contradiction to what is suggested in the original article.

stever

Sure you don't have your pics reversed?

carboy21

previous photo shows a darker oil

thecardoc3

stever said:

Sure you don't have your pics reversed?

LOL.

rjmccorkle

i have a new dodge durango w/ penns semi synth and the computer is just* telling me to change it at 7300 miles- I believe that's another "severe usage" per the recommended semi synth mileage on the bottle / dealer setting. I figure it can last to 10k but not sure if it voids warranties if I don't... at the same time they say it's fine to go elsewhere for your oil change because dodge is overpriced at $49 minimum and they even recommend finding the $39.99 oil change coupon because it's overpriced. Then $19.99 for tire rotation when you can get it free at discount tire? Silly. Don't be fooled by the "$0.00" on the mopar website when you go to book your service.

Anyone have recommendations when to change semi synth?

edcarcal

I had the opportunity today to look at this blog, and oil change frequency has always been of interest to me. While I have always felt synthetic oil is the way to go, it is only recently that manufacturers have started adding additives for high mileage vehicles to combat seal degradation – my experience over 45 years has been that older synthetic oil versions in high mileage cars have tended to produce engine seal leaks, which may have turned more than a few users off them. Why go with semi-synthetic, and not synthetic? Cost savings are misleading.

Regarding the issue of change frequency, one thing the bloggers above have missed is the impact of environmental conditions on the life of the oil. No matter what change frequency is recommended or what oil is used, where you live is a big factor in how fast the oil will degrade – these include very large temperature extremes, altitude, humidity and air condition (dust, smog etc.). It may not be obvious how these affect your oil, but believe me, it’s significant. For this reason and the fact I live where most of these factors are an issue, I derate the manufacture’s normal driving mileage recommendation for normal driving by 50% and have never had an engine problem. In the case of a 15 year old Cadillac Deville, this has been every 5k to 6k miles. Overkill? – prove it.

I still have one question not satisfactorily answered – for cars that are not driven very far in a year (e.g. 3k), what is the risk of perhaps changing the oil at intervals longer than the 6-7 months most companies recommend? It seems to me if the shelf life for synthetics is very long, this is too restrictive.

thecardoc3

edcarcal said:

I still have one question not satisfactorily answered – for cars that are not driven very far in a year (e.g. 3k), what is the risk of perhaps changing the oil at intervals longer than the 6-7 months most companies recommend? It seems to me if the shelf life for synthetics is very long, this is too restrictive.

First there is no single answer to this question because the answer will be unique to the way any given car is driven and what the actual specifications are for the oil it requires. Then we have to consider exactly what someone buys and puts in the car.

For example.
A car that is driven further than another for an average trip will see it's oil degrade slower.

Even though both cars may go 3000 miles a year, if one car is driven two miles each time it is started and the other is driven twenty, the one driven further will have less crankcase acid produced for the oil to have to contend with. The crankcase acids produced will significantly shorten the life of the oil on the car only going two miles essentially four times a day.

Take four cars driven in the exact same manor with different engine oils. For simplicity let's only use the North American specifications. This list would be much longer with the Euro's added in.
One car using 5W20 with an O.E. approval like GM's dexos1 specification.
One car using any brand off the wall labeled synthetic that is NOT a dexos1 nor ACEA approved product.
One car using a product approved for ACEA A1/B1
One car using a product approved for ACEA A5/B5

Your goal at this point would be to list the oils in the order of lifespan based on the shortest first and the longest last.
The answer would be the synthetic, the ACEA A1/B1, dexos1, and then the ACEA A5/B5.

To meet the dexos1 specification a product does not have to be a true synthetic but it will outperform many products that are labeled as such. dexos1 is a long life product but falls short of the ACEA A5/B5 requirement.

With just these two variables predicting real oil life for any given individual is little more than a guess.

william_10

This article is barely good enough for dummies. One of the easiest ways to prolong the life of any engine or machine, is service the fluid and filters. I have not seen an engine "too clean" in 42 years of working on them.
Without going into details, the easiest way to know you should change the oil is by how dirty it looks on the dip stick. If it looks dirty, the oil draining out will look even dirtier.
The author says to run the oil until "black". That is one of the most dumbest pieces of advice. Almost like saying "don't clean your windows until they are difficult to see through".
In short, the longest lasting and best running cars that I have seen, are ones which have had frequent oil changes for the engine, transmission, power steering, differential, and cooling system. I should also add brake fluid to the list. I've seen many cases of dirty contaminated brake fluid.

Synthetic oils do last longer, but they get contaminated and oxidize also. So my advise is stay on the safe side of maintenance.