Case for the 3000 Mile Oil Change?

[rg144]

quote:

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Originally posted by Grossomotto:
Ask yourself this. Which used car would you buy. The one with 3,000 mile oil changes or the car with 7,500 mile oil changes?

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The 3000!

My son's car is a '90 Mazda Protoge with 175,000 miles on the odometer and it runs great! It had documented 3k OCI. We bought it from a nice, concientous, lady. NO varnish/sludge.

I am not saying 3K is the limit to engine oil life. But ... if we didn't have BITOG would we know any better then that little 3k sticker?

 

[Patman]

quote:

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Originally posted by Grossomotto:
Ask yourself this. Which used car would you buy. The one with 3,000 mile oil changes or the car with 7,500 mile oil changes?

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The one with the shinier paint!

 

[Frank D]

Jbas, I have no problem with people who use their truck for work purposes but the people who buy these large pick ups and SUVs strickly for personal transportation even commuting in them (1 person in the vehicle) are wasting a dwindling resource. People buy these vehicles because they see a commercial on television where a professional driver is doing 60 mph in fake snow and they get out on the snowy road and try and drive that way and guess what vehicles I see flipped over or rolled down an embankment. Right, their's. I have done 17 of my 18 years commuting in Nissan Sentras with front wheel drive and 5-speed transmissions without ever a problem. Or the even better reason, "I want to feel safe on the road". IMO those are the most dangerous drivers on the road. I know people will scream it's their freedom to drive what ever they want to but when does personal responsibility come into play. Will it take mandated gas rationing as we had back in the 70s to get people's attention? With worldwide demand for gas increasing that could be come a reality again.

 

[Mystic]

Some people like to jump down the throats of anybody who says that they like to do 3000 mile oil changes. But think about it-if a person is using conventional motor oil and a standard oil filter, and also doing the oil changes themselves, how much will an oil change cost, especially if you can find conventional motor oil on sale? Assuming the car or truck uses four or five quarts of oil, you can find the oil for a dollar something a quart, and an oil filter for say four dollars, an oil change will cost you smething like ten dollars. This is high finance? Assuming four oil changes a year that i fourty dollars a year. How much is your car insurance?

I performed 3000 mile oil changes on my previous Saturn and it still apparently had some sludge in the engine judging from the first oil filter I used in the Auto-RX cleaning, and judging from the fact that a oil seal leak stopped after I did the Auto-RX cleaning.

Now if you are using an expensive oil it makes sense to try to go further on each oil change. But you should be able to go further with the expensive motor oil. If you go 8000 miles per oil change using Mobil 1, and if it costs about twice what the conventional motor oil costs and you change th conventional oil at 4000 miles, things probably come out about equal in the end. Using the expensive synthetic oil might result in a cleaner engine, but doing an occasional Auto-RX cleaning will also result in a cleaner engine. Just my thoughts.

 

[Frank D]

Mystic, first of all nobody is jumping down anybody's throat. Secondly, I wasn't talking about saving a few dollars on an oil change. You are missing the big picture. Can you say conservation? And for the people who say the wear particles double after 3k, what are we talking about 4ppm to 8ppm. My God the engine is going to fall out. If your Saturn had sludge with 3k oil changes, do you think there was something else causing it and not the 3k routine.

[ May 29, 2005, 11:27 PM: Message edited by: Frank D ]

 

[1sttruck]

I've posted the stuff below before. One needs to be careful about wear rates are calculated, as the data below seems to suggest almost the exact opposite of what was summarized by the authors. he data seems to often ne referenced by others in justifying longer oil change intervals as 'there is more wear in the 1st 3k miles'. There is more wear in the first 1k miles, much lower in the next 2k, and then it appears to double after that. I haven't checked other intervals like this, but it'd be interesting to do so.

**************************
Using the the synthetic oil study at http://neptune.spacebears.com/cars/stories/mobil1.html , and looking at the Mobil 1 5W30 Super-Syn Formula data, we have for the first six 1k samples:

miles, iron, make up oil

1k 10 0
2k 12 0
3k 14 .5
4k 19 .5
5k 23 .5
6k 26 .5

It's evidently a 5.7l engine with about a 6 qt sump. Looking at the iron rate normalized for sump + make up oil, engine displacement and mileage, we have the rates shown in the second column. We need to look closer though as the rate at 2k states 6.3 but that's different than the 10.5 rate at 1k, so we need to determine what the rate was for the second 1k miles, then the next 1k miles, etc., which is what we have in the third column. Since there is a big jump going from 3k to 4k, the data suggests that it's reasonable to change it at 3k. I'll take a closer look at how to determine the rates for each sample interval, as so far I've done it this way just because it's easy to do.

1k 10.5 10.5
2k 6.3 2.1
3k 5.3 3.3
4k 5.8 7.4
5k 6.1 6.9
6k 6.1 6.2
***********************************

 

[jbas]

"Jbas, I have no problem with people who use their truck for work purposes but the people who buy these large pick ups and SUVs strickly for personal transportation even commuting in them (1 person in the vehicle) are wasting a dwindling resource."

"But think about it-if a person is using conventional motor oil and a standard oil filter, and also doing the oil changes themselves, how much will an oil change cost, especially if you can find conventional motor oil on sale?"

Both great points. We are a wasteful society, but there are a zillion gallons of the stuff under Iraq.

 

[Frank D]

Oh, I thought we were over in Iraq to liberate the people. How silly of me. I guess we are over there to liberate the oil.

 

[bbcmat]

Throwing good motors into the wrecking yard is a waste - how many vehicles with careful owners (ie: strictly follow 3K or 7.5K changes and have the metality that things like this are a priority and are important to the life of a vehicle) - are going to the wrecking yard due to oil-related failures? Quantify the additional value 3K oil changes give to the vehicle at trade in time - vs a careful wash / buff / wax?

Follow the severe duty OCI schedule and be done with it. The "sludge monster" factory failures are freaks and should be delt with on an individual basis.

IMO

MAT

 

[1sttruck]

I numbered some portions of the previous post.

1.) I wanted to normalize for displacement too, as it seems that 3 liter engine with a 6 qt sump would produce less wear metals than a 6 liter engine with a 6 qt sump.

2.) The 'wear rate' in the 2nd column is iron per 1k miles, which seems to be a common way a common way of looking at wear metals over different intervals. Everyone seems to stop at this point and draw their conclusions, but an obvious problem is that one already stated that the average rate was 10.5 (at 1k miles), so it can't be 6.3 (at 2k miles). Since the average was 10.5 at 1k miles and it dropped to 6.3 at 2k miles, what was the rate from 1k to 2k miles ? The 1k to 2k mile interval had to be less than 6.3, as it was combined with 10.5.

By not determining what the rate was for each 1k interval, instead of just averaging out to the interval, we're throwing away the most important data. If the average is the same at every 1k interval then the rate for each 1k interval will be the same, but if it's not, then it's not.

3.) This data suggests that although there are more metals at duing the 1k interval than others (is it the first 100 miles ? 500 miles ? is it dissolving some previous films ?), one still sees about a doubling in wear metals from 3k to 4k, so a 3k oil change might be suggested.

**********************
1.) It's evidently a 5.7l engine with about a 6 qt sump. Looking at the iron rate normalized for sump + make up oil, engine displacement and mileage, we have the rates shown in the second column.

2.) We need to look closer though as the rate at 2k states 6.3 but that's different than the 10.5 rate at 1k, so we need to determine what the rate was for the second 1k miles, then the next 1k miles, etc., which is what we have in the third column.

3.) Since there is a big jump going from 3k to 4k, the data suggests that it's reasonable to change it at 3k. I'll take a closer look at how to determine the rates for each sample interval, as so far I've done it this way just because it's easy to do.

1k 10.5 10.5
2k 6.3 2.1
3k 5.3 3.3
4k 5.8 7.4
5k 6.1 6.9
6k 6.1 6.2
*************************

 

[labman]

Hummmmmmm! How did this get to be an anti SUV thread? OK, I bought a truck I didn't have to have in 1977, and have mainly used it for hauling my self around, although I have saved myself many a buck hauling stuff around with it now and then. The garden does much better for occasional visits to the horse farm.

However, it was a Chevy LUV. It got much better mileage than the crappy Valiant I had then. Cars are much better now than in 71 when the Valiant was new. My 02 Cavalier with the Ecotec 4 gets twice the mileage it did and likely has the same performance. The Grand Am I had got over 30 mpg on trips and could run away and hide from any 4, 6, or 8 I ever owned. They are also FWD, nifty in the snow and ice, and have other mileage eating options like A/c the Valiant didn't.

In the mean time, their performance may be a little better, but even the best of today's trucks hardly get any better than the 20/25 city/highway my LUV does. So it will keep getting 6 quarts of Pennzoil 5W-30 every 3 months regardless of how few miles I drive it. If trucks made the improvements cars have, I would at least wish I could afford a new truck.

Driving a guzzler you don't need, isn't near as bad if you don't drive hundreds of miles every week. Live 5 miles from work, and your F150 may use less gas than somebody's hybrid

 

[Mystic]

Frank D., there is apparently some evidence that earlier Saturn models had some sludge build-up problems around the rings. Of course, since that time Saturn is now using different engine technology. AND, Saturn was basically insisting that people needed to do 3000 mile oil changes on Saturns because of the metal timing chains that were being used instead of belts.

There have been other vehicles that were supposed to have some sludge problems. According to some people some Toyota cars and vans, and some vehicles such as the Datoka SUV, at least with certain engines, had some problems.

I agree that we need conservation. I don't want to waste any motor oil. But I can think of bigger wasters of oil then somebody doing three-four oil changes a year on a car or truck that uses 4-5 quarts of oil. And if the oil is recycled (like I do) the used oil is used for other purposes. It can even wind up back inside an engine somewhere else. I hardly think of myself as a big waster of fossil fuels. I have been driving small cas for several years. I have one small car. Every day I see people who seem to own a fleet of vehicles and people driving around in massive SUVs or pickup trucks. Now, some people have to have those big vehicles. If a person had a large family an SUV might be more economical then three-four small cars. Farmers and ranchers have to have their pickup trucks and large trucks if we expect them to continue to produce food for the country. It all depends on a person's situation. I don't automatically condemn somebody driving a big SUV-I don't know that person's situation. But I can also remember a few years back when some people in their SUVs used to kind of look down their noses at me in my small car. ome of those people might now be in the market for a small car themselves.

 

[Gary Allan]

quote:

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1.) I wanted to normalize for displacement too, as it seems that 3 liter engine with a 6 qt sump would produce less wear metals than a 6 liter engine with a 6 qt sump.

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Okay ..so you have a side note that this is a 5.7 liter engine. Data is uneffected ..only in how it is interpretted.

quote:

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2.) The 'wear rate' in the 2nd column is iron per 1k miles, which seems to be a common way a common way of looking at wear metals over different intervals. Everyone seems to stop at this point and draw their conclusions, but an obvious problem is that one already stated that the average rate was 10.5 (at 1k miles), so it can't be 6.3 (at 2k miles). Since the average was 10.5 at 1k miles and it dropped to 6.3 at 2k miles, what was the rate from 1k to 2k miles ? The 1k to 2k mile interval had to be less than 6.3, as it was combined with 10.5.

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Okay ..now with the edited original 10 evolving to 10.5 and the 2k being 12 I can now integrate (10.5 + 12.0)/2 = 6.3

quote:

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By not determining what the rate was for each 1k interval, instead of just averaging out to the interval, we're throwing away the most important data. If the average is the same at every 1k interval then the rate for each 1k interval will be the same, but if it's not, then it's not.

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Well ...okay .. sure we lack the normal progression of 10,20,30,50 to get a 10ppm average. But since it's not ...can we offer something beyond, other than the assigned quantitive value of the data, beyond "it's not"?

quote:

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3.) This data suggests that although there are more metals at duing the 1k interval than others (is it the first 100 miles ? 500 miles ? is it dissolving some previous films ?), one still sees about a doubling in wear metals from 3k to 4k, so a 3k oil change might be suggested.

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I'm sure that some residuals are suspended in the new oil. One can also believe that new films are in formation ..and that formation ends at some point. So although one could assume that the upramp @ 4k indicates a need for changing the oil out @ 3k, we don't know if we are viewing a stabilized sample.

btw- have you plotted this out beyond 6k? Are there any more spikes or dips? If not, then I submit that this suggests that between 0-4k is indicitive of chemical exchanges in progress. :^)

 

[1sttruck]

Let's try restating the problem a bit:

0 to 1k iron rate per 1k is 10.5,

0 to 2k iron rate per 1k is 6.3;

What was the 1k to 2k iron rate ?

If it started at 10.5 per 1k and dropped to 6.3 per 1k at 2k miles, it had to be 2.1 as (10.5+2.1)/2=6.3.


*************
1k 10.5 10.5
2k 6.3 2.1
*************

 

[slalom44]

It appears that most people believe that oil with over 3000 miles produces less wear than oil with less than 3000 miles. I disagree, and here's why:

The oil filter gets more efficient over time because particulates trapped in the oil plug the larger, more direct path through the filter. In the Mobil 1 test mentioned, more larger wear particles are being removed. As the filter's pores get plugged with more particles, it filters to a finer particulate size.

You can argue that this will cause the filter to go into bypass mode more often, and I'm sure it does. But when it's not bypassing, it is removing more particles. and the average particle size remaining is getting smaller.

Therefore, you should not automatically believe that used oil produces less wear metals than new oil. If they ran without any oil filter (like Bob did), I'd bet money that the results would be quite different.

 

[medic]

quote:

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Originally posted by gulledge:
With everyone pushing for longer OCI's arn'these wear particles just getting more and more causing more and more wear, even though the oil may be good.

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I didn't read all of the responses, so please forgive me if sombody already brought this up.

For some reason, there is more wear in the first 1000 miles after an oil change than during the rest of the OCI. I understand the theory behind your question and don't quite know how to answer your question. So, this just adds to your question. Are you causing more wear by running oil longer or changing more often?

 

[GreeCguy]

Alrighty then - let me throw this into the pot -
My Dad is a farmer - he still uses the same tractors he bought years ago, two 1965 Case diesels, (a 530 and a 730). Both of these tractors have been used and are still used on a daily basis in mud, dirt and dust. They work pulling heavy equipment in temps well over 100 degrees, (his farm is in Florida). Every great once in a while, Dad would pull the dipstick and say, "The oil is looking kinda dirty." That's when we would change it - no log of hours kept and neither one of us could ever remember when the oil had last been changed, (Wasn't it last summer Dad?"). These tractors are still going strong and have never been rebuilt.
Personally, I try to change my oil at the 5,000 mile mark, but I'm not religious about it. I think a lot depends on the motor itself. I've had cars that I babied that died at 100,000, (who remembers Chevy's "Odd fire" V-6?) I've had others that I abused and they simply wouldn't die, like my first car - a '69 Buick with a 350 V-8, (a Buick V-8 mind you). In the three years I owned that car I might have changed the oil one time. And yes, it finally quit running - when I wrapped it around a tree. Like I say, just my two cents.