Why change oil more often than recommended intervals?

[Thik]

Originally Posted by trustbran

Have you seen 15k oil...its frothy, thicky, slothy, etc..... Like try not brushing your teeth for 1 week and see the gunkyness that prevails, not that I've tried this LOL.. Yah 5k oil changes for me keeps the engine mouth so fresh!

-Brandon

Hope you are joking. That was the least scientific assertion and most illogical analogy possible.

[Thik]

Originally Posted by TomHudson

The manufacturers are also looking after their own financial interests. The argument to say that BMW designs everything the upmost engineering it shouldn't be questioned his silly. I don't have a spare tire in my car, I have a can of foam. I'm assuming that's better than actually having us there? Or is it because they save money?

North of the border I do a lot of commuting, and a lot of weather changes. In other words, there's a lot of other factors the mitigate the decision to change the oil. I know people that never do oil changes and just add oil over years, and the engine still runs.

Anyway, changing The oil is cheap peace of mind, where an engine is $25,000. And I want to enjoy it for as long as I can

I don't buy the argument that manufacturers are trying to save money by increasing oil change intervals. Porsche, Audi, MB all do not pay for oil changes and they have similar recommended oil change intervals.

I think the fact is that these synthetic oils are so good and do indeed perform to their specs well beyond 15,000miles. That's why manufacturers recommend 15k change intervals. Anything more frequent is unnecessary and wasteful from a technical stand point.

But if changing the oil every 100 miles makes someone feel better and don't mind the time and money, it's worth it for that person.

[trustbran]

Originally Posted by Thik

Hope you are joking. That was the least scientific assertion and most illogical analogy possible.

I hope you know that I'm joking but by your reply I'm assuming you don't.... Realistically I do change oil at 5-6k for peace of mind and honestly I look forward to it

-Brandon

[TomHudson]

Originally Posted by Thik

I don't buy the argument that manufacturers are trying to save money by increasing oil change intervals. Porsche, Audi, MB all do not pay for oil changes and they have similar recommended oil change intervals.

I think the fact is that these synthetic oils are so good and do indeed perform to their specs well beyond 15,000miles. That's why manufacturers recommend 15k change intervals. Anything more frequent is unnecessary and wasteful from a technical stand point.

But if changing the oil every 100 miles makes someone feel better and don't mind the time and money, it's worth it for that person.

My understanding was that blow by (that exists in these modern perfect engines) can create chemical reactions with moisture that reduce the effectiveness of the oil itself and increase wear on engine components...
For what its worth I do more frequent oil changes, but certainly not every
1000 miles! It does give me peace of mind with an extra cost of $200/year, so why not?

I'm pretty sure the racing teams are not staying within these guidelines!

[takrdown]

My two cents but the oil changes aren't so much for the oil as they are for the oil filter. That is the experience I have in the submarine Navy. Oil will not break down for a long period of time but those filters stop doing their job after a few thousand miles.

The argument isn't so much that BMW engineers don't want to do the changes after 5000 miles.....it's the BMW accountants who see BMW paying for the oil changes for the first 50K.

[beats]

Originally Posted by takrdown

My two cents but the oil changes aren't so much for the oil as they are for the oil filter. That is the experience I have in the submarine Navy. Oil will not break down for a long period of time but those filters stop doing their job after a few thousand miles.

+1

[kaede]

Always changed the oil every 7.5-10k km (approx. 4k-6k miles) or every half a year whichever comes first. Never quite liked the oem recommended OCI and it is a "cheap" peace of mind thing that i enjoy DIY'ing. Whether or not it is detrimental to the health of the engine i highly doubt... but i am no oil expert.

Some other fluids that good ol' bmw says are lifetime such as MT/DCT fluid or Diff fluid is basically crazy too... no fluid is "lifetime." By lifetime they might mean till the end of warranty period lol, and after that they don't give a crap if you transmission blows or develop problems because that's how stealership makes money mostly - by fixing our cars. I am sure we all probably changed our MT/DCT fluid once or twice before, or do the skeptics here never change it because BMW says "lifetime" =D?

anyways. ya. i'd rather spend that extra money on oil every year personally. Cheers!

[8600RPM]

Well for what it's worth bmw themselves have changed the interval to every 7 to 10k.miles depending on driving but 10k is the longest. My guess is turbo engines are harder on oil but nonetheless when they make a change that will cost them money I put credence into it.

I've always done every 7500 to 10k on my last e92 m3 which did 100k problem free miles

[kaiv]

I change my oil every 3k or so. Some track miles. Why? Because I can and from my experience with the S54, the Castrol TWS tends to stain/discolor the internals to a gold color. I want my motor to stay looking pristine silver

[dmppdx]

Originally Posted by Three Pedal Steve

I wonder about high revs when the engine is cold and the effect on the rod bearing issue?
And wife does not understand why I will not allow Valet parking of my M3.

I have always suspected that higher revs, or even just a lot of throttle even at low RPMS, when the engine is cold is a major factor with the bearing failures that take place in these engines since bearing clearance would change with the temperature of the engine and you might not always have adequate clearance if you don't let it warm up slowly.

It's not like BMW doesn't know exactly what impact bearing clearance has, but there are always a trade offs and since there a a significant number of engines that have made it to 100K plus without any issues, bearing clearance and design isn't the only factor. Clearly, there is some factor in how engines are treated that have a huge impact. And while everyone knows that you need to be careful with a cold engine, it's something that is very subjective for how slowly to let it warm up. So I'm sure there are people out there that think they are letting their engine warm up sufficiently even when they are not. I also question how people seem to think that when warming an engine up its all about the RPM since I have heard that if you give a car a lot of throttle at low RPMs, its pretty hard on an engine's bearing regardless of it being warm or not, so people who think they are letting their engine warm up OK by just keeping their RPMs low, even though they are compensating for the low RPMs by giving it more throttle, are harming their engines.

My guess is that wider bearing clearances might make not warming up a cold engine less problematic, but the wider clearances would potentially cause issues else where, particularly with such a high reving engine, so they weighed all the options and designed the engine the way that is was because they figured that bearing design was the best over all given all the pros and cons.

[squartus]

My bearings were shot at 30k before supercharged etc, always warmed up and 7500 mile oil changes. As many people can attest its not to do with warming up or matience, some of these engines are just coming from factory with closer tolerences than others etc. You either get one that blows in 20k, is worn to shit and going to blow at 60k or you get one that breezes past 100k no problem.

Far to many people that baby the car when its cold and change fluids like its a relgion and still spinning bearings, now poor care of the car will deff make the problem worse.. but the root problem is not the owner of the car its the maker of the car.

[XxMerlinxX]

Originally Posted by omniphil

Do I win a prize?

I come to the internet to learn things not to put others down to make myself feel better. Its your choice as to what you want to learn. I offer some experience and wisdom to you, If you don't think what I have to say is valuable you don't have to follow it, its your car you are welcomed to do what you want based on what you think. I am totally cool with that. I am offering my side of the story, nothing more.

Would you like to learn something?

Detergents/Cleaning additives are abrasive, That's pretty much the purpose, They break down the sludge and junk in the engine and suspend it in the oil. Those cleaning additive wear out/burn off after some period in the first 1500 miles or so. You are then left with the wonderful anti wear additives. That's good. (They wear out too, much after a much longer time)

So guess what you are doing each time you change your oil? Yup, You already guessed it.

You obviously don't want to go too long on an oil change as all the additives will wear out, Only an oil analysis will tell that, but you can tell from the many oil reports already out there that for most people 10,000 miles is totally fine. Sometimes longer.

I change my oil in my vehicles every 10,000 miles. I use Mobil 1 0W-40 because it flows the fastest on cold starts (a good percentage of engine wear is cold starts) In my opinion there is no reason to use anything other than a 0W oil in a normal driven street car. Why would you want less protection?

Imagine how many more times those abrasive detergents are in your engine if you changed it every 3000 miles for example?

Guess what race oil is? Oil that has the detergents greatly reduced because its changed very often. Making sense yet?

There are quite a few reason to change the oil sooner, most of which you can all guess, but for someone like me that daily drives my car, I don't need shorter intervals, in fact I want as long as interval as possible without the oil losing it ability to lubricate properly and trap dirt and crud.

In the grand scheme of things if your aren't tracking your car all the time its not going to make a big difference if you change it at 3000 miles or 15,000 miles. But if your anal about your car and every little ounce of prevention is appealing to you I would not change it very often even though it seems counter intuitive. I was just trying to let you guys know that contrary to popular belief engine wear will decrease as the oil ages (to a point).



Take this information and do with it what you wish. I am just giving you some information. It's on the internet so it has to be true right? You don't have to believe any of this, this is just what I believe.

Speaking of learning something...

Detergents are not abrasives. There are two main types of cleaning additives that go into an add pack for a motor oil, detergents and dispersals. Detergents encapsulate particulates in the engine and form a barrier film, that then suspends the particulates in the oil so that they don't form deposits on engine surfaces. Their ability to do this is limited though, so when all of the detergent is saturated, the oil must be changed so that deposits don't form.

Detergents are also basic, in that they're on the opposite end of the pH scale from acids. Acids are formed due to the nature of combustion, and so something has to prevent the acids from corroding the internal parts of the engine. When the basic detergents come into contact with acids, they neutralize, much like an antacid settling your stomach. This is what the TBN (Total Base Number) references on a used oil analysis. If the oil is still basic, it can neutralize more acids as the combustion process continues. If the TBN is too low, you need to change your oil so that acid buildup doesn't occur.

Most synthetic oils will retain their TBN for 7k-10k miles, but your driving habits, tolerance stacking, oil preference, etc. will all play a role in how long it actually lasts. So, as with everything, your mileage may vary.