The enormous amount of misinformation about BMW's Oil change intervals

[carve]

The oil change monitor doesn't evaluate the actual oil life remaining, it just uses the amount of fuel used, engine temps metrics etc. The

This is what you said is unsubstantieted speculation and misinformation. My main argument is that it is NOT. The system DOESN'T evaluate actual oil life remaining and, unless your oil is really messed up, the interval is based just on fuel burn, miles, temps, and things like that. There is not built-in oil analysis lab that tells the car just how good the oil is.

[markinva]

Originally Posted by carve

(I thought I lost my mind when this was moved to M3)

OK...our oil pumps aren't electric- only the water pumps.

7qt of syn is WAY preferable to 4qt of fossil oil for resisting coking and for making is last longer. Still, hot running, 100hp/l turbo engines are more demanding on the oil, but the interval appears (yes- I'm speculating) unchanged from BMW's normally aspirated engines. That doesn't make sense. We also have no information about longevity goals BMW intended. I imagine the majority of people buying BMWs brand new don't keep them beyond the low 100k range, and already expect big depreciation, so that is a likely factor (yes, I'm speculating)

I'd be much less concerned running a (non-M) normally aspirated engine on the recommend change interval than a turbo or M engine.

In fact, when Subaru started importing turbocharged cars again (2001?), I think they had like a 5-7.5k mile interval, even on synthetic. By 2005 they changed that to 3,750 for all turbo engines, even if driven under mild conditions. Previously that was the interval for "extreme conditions" drivnig. Now they define merely HAVING a turbo "extreme conditions". The interval was implemented retroactively to ALL turbo subies. Think about it...they reduced their interval from 2x as often as BMW to 3-4X as often!

subaru recommends/uses dino oil... I've had 5 subarus (3 of which were turbos). It's true that they allowed synthetic and wouldn't change the intervals because of it.

[markinva]

Originally Posted by carve

This is what you said is unsubstantieted speculation and misinformation. My main argument is that it is NOT. The system DOESN'T evaluate actual oil life remaining and, unless your oil is really messed up, the interval is based just on fuel burn, miles, temps, and things like that. There is not built-in oil analysis lab that tells the car just how good the oil is.

ok, but the "unless your oil is really messed up" part is very important. Also, neither you nor I know for sure how messed up it has to be.

[carve]

Originally Posted by markinva

ok, but the "unless your oil is really messed up" part is very important. Also, neither you nor I know for sure how messed up it has to be.

It certainly is important- especially since the oil can't be visually inspected (unless you pull the oil filter cap).

You said the following was wrong...
"The oil change monitor doesn't evaluate the actual oil life remaining, it just uses the amount of fuel used, engine temps metrics etc"

It doesn't evaluate life...it just tells you when you're turning your engine to metal shavings or are getting a lot of water into your crankcase (e.g. coolant leak, lots of cold driving, blowby, etc.)

I'm not saying the system is worthless- it's very clever. I just wish I knew what sort of engine life they were targeting, what sort of testing backs that up, and what sort of safety factor they have. e.g. in the 80s, Ford thought 60k miles from their FWD automatic transmission was an acceptable design life. In the 90's, when BMW first importated V8s to the US, they quickly failed due to our crappy gas.

[KKelly]

158k on my '00 323iT using only factory intervals for changes. I don't doubt that maybe more oil changes might add some fuel efficiency or longevitiy but maybe not worth it. It isn't burning or using oil at all.

[mr.i]

Originally Posted by 02themax

My SA informed me that BMW is moving towards 37K intervals (60K in Canada)! They are using the 15K (25K CDN) intervals to ease people into the higher mileage intervals, they don't want to "scare" people. It seems as if that plan has already failed! I change the oil in my G35 every 12K with synthetic oil and have 140K on the odo with no problems. It'll be interesting to see if what he said is factual or purely speculation. I will say that with all of the oil consumption problems I don't see how this could be true.

Personally I have no problem with the current interval time frame. I strongly believe that the turbos would fail prematurely if the oil wasn't in good condition. We'd be seeing alot of 335's blowing smoke out the tail pipe, even with low KM's, and even more with sludge problems but I guess only time will tell. I also agree with the statement above about the CPO warranty and BMW's reputation, so until I see further evidence that damage has been done due to long intervals I'm going to keep on .

I'm going to adhere to the established recommended service interval and cut it in half. I've got a reputation around town for keeping my cars in above average condition and while I'm not sure who is putting the word out, my used autos fetch premium prices from both private buyers and my favorite dealer. That subtle peace of mind that I get from making sure my equipment is maintained to high standards is my personal decision. The rest is self explanatory.

[BMRLVR]

Originally Posted by carve

The oil condition sensor measures the conductivity of the oil. That may tell you how much water or metal shavings are in the oil, but not much else. Go ahead and change your oil on your own and then tell me if the computer lengthens the time until it says you're due for your next change (hint: it doesn't!). Based on this (admitedly limited) evidence, it's reasonable to infer the sensor is more of an "oh crap- the oil is all messed up and contaminated even though we predict it should have more life left based on our algorithms" device than something that actually measures oil condition to any degree that'd tell you when it needs to be changed.

I used to do oil changes on my 330i every year before winter storage and the CBS would not adjust the interval after the oil change. It always stayed the same. The car took two years to get to my first service and I changed the oil two times before I had the dealer do it. The service still was at 25k KM.

Originally Posted by mr.i

I'm going to adhere to the established recommended service interval and cut it in half. I've got a reputation around town for keeping my cars in above average condition and while I'm not sure who is putting the word out, my used autos fetch premium prices from both private buyers and my favorite dealer. That subtle peace of mind that I get from making sure my equipment is maintained to high standards is my personal decision. The rest is self explanatory.

1/2 of the normal interval is a good interval IMO.

Originally Posted by markinva

This stuff spreads like wildfire. I've seen these statements a million times on throughout BMW forums:

-The oil change monitor doesn't evaluate the actual oil life remaining, it just uses the amount of fuel used, engine temps metrics etc. The Condition Based Service (CBS) interval is not sophisticated enough/reliable.

-The Maintenance intervals proposed by BMW will get your car through warranty period, but after that get ready for massive repair $$$.

-BMW went to extended (15k) intervals based on the oil change monitor only when and because they started paying for maintenance. The intervals are only that long because BMW wanted to save money/they are paying for it

Is there one shred of evidence for any of the three above "facts"? People routinely say this stuff on every bmw forum I've been on, yet it's all theory and speculation. Not only that but it is weak theory and weak speculation.

Consider:

-Thousands of people have been using the normal CBS for years, and you don't see BMW engines grenading very often. Many times more people stick to the CBS than those that don't. Thousands of people have gone 100k+ miles on the CBS intervals as they have been used for many years.

-The CPO program would be an utter disaster if the oil change intervals were too long, as these more used BMWs would show lots of signs of engine trouble and cost BMW $$$ in CPO repairs.

-BMW's around the world come with the SAME CBS oil life system- and yet the USA is one of the ONLY countries in the world where maintenance is covered. You really think BMW would threaten their worldwide reputation, engine reliability and CPO programs in every country in the world, just because maintenance is covered in the USA for four years?

-The condition based service does measure oil quality- at least at some level. Please look at the pdf file on post #3 for some evidence.
http://forums.bimmerforums.com/forum...d.php?t=954499

-BMW is not the only manufacturer to rely on CBS, porsche, mercedes and others do it too.

Please note that I have absolutely no problem with those that want more frequent oil changes- heck I am seriously considering getting the tischer kit and doing my own oil changes in between intervals. That's not my point here. My point is that there is massive missinformation that gets repeated on here and people need to be made aware that it isn't factual.

The one thing that I know is factual is that the CBS does not measure the condition of the oil. You can drain the sump and do an oil change and the interval remains the same as before you changed the oil, I know this because I have changed the oil on my BMW's and noticed the service interval was unchanged after the oil change.

Anyhow no matter how you feel about all of this, as a Mechanic I feel that the service intervals are too long...... I base this on teardowns of engines that have had regular maintenance at 8K KM intervals and ones that have had extended 16K KM+ intervals. One thing I can assure you is that you can easily tell the difference in the cleanliness and lower wear on the engines with more frequent oil changes. The damage/wear will not be noticed in the first 160K KM of the engine but will usually start to manifest itself there after.

I have said this in another thread, If you are not going to keep your car out of warranty follow their service interval but if you are going to keep your car for the long haul cut their intervals in half at the least. BMW and the other Manufacturers that use the CBS system or other similar system base the service intervals on engineers recommendations. I can tell you this for sure, engineers don't know it all. When we have a failure or issue on our heavy equipment at the mine I work for (Caterpillar 797 and Komatsu 930 Haul trucks) engineers from the manufacturers come looking and taking pictures and asking us for our recommendations and more times than not the mechanics help them with the redesign of the affected components by giving them their input. While engineers are very intelligent individuals nothing beats seeing something work in the real world and even better, seeing it fail and knowing why it did. Engineers know theory from behind a computer screen or from a sheet of paper and that is the problem. something can be engineered to work and be durable and look good on paper but in service it can fail right out of the gate.

I am not sure of your profession but my profession is a mechanic, (both automotive and heavy equipment) and I suggest you take some advice from someone who knows. I am not a doctor or lawyer so when it comes to medicine or law I seek their advice. BMW and other car manufacturers that are using CBS or similar systems have two things in mind profit, and environmental relations. From the profit stand point the less maintenance they do inevitably the more parts thay sell in the end after the warranty is up (or the less oil and filters they pay for in the event of paid maintenance) and from the environmental stand point the less waste oil they are producing.

To sum up; car companies are profit based and highly scrutinized organizations don't think that all of their motives are pure...... If I ran a business I would spend the least amount of capital I could to keep profit up while maintaining customer satisfaction...... I think this is what is happening BMW and all other manufacturers are walking the fine line of keeping the customer happy while maintaining a good corporate image and maximizing profits.

[MSoldier]

I was going through the service mileage and my oil mileage went from 10k to 9k to now 8k, although the monitor reads OK and I recently topped it off a few weeks ago the mileage down for an oil change. I'll see what happens.

[Radiation Joe]

This whole thread is useless without numbers from actual oil analyses. I believe the nay-sayers be surprised at the results that will clearly show that 15k is no problem at all.

I change at 7500 mile intervals for peace of mind, but am sure, absolutely sure, that 15k miles is not a problem. Changing oil at the recommended intervals is better for the environment as well.

I just finished a couple of track days that brought my service indicator from 12k miles down to 7k miles. So I feel the service computer is working fine.

[mPlasticDesign]

Originally Posted by Radiation Joe

This whole thread is useless without numbers from actual oil analyses. I believe the nay-sayers be surprised at the results that will clearly show that 15k is no problem at all.

I change at 7500 mile intervals for peace of mind, but am sure, absolutely sure, that 15k miles is not a problem. Changing oil at the recommended intervals is better for the environment as well.

I just finished a couple of track days that brought my service indicator from 12k miles down to 7k miles. So I feel the service computer is working fine.

I totally agree with everything you said. I mention in another thread about the environmental impact of changing oil more/less often and I got laughed out of the thread. I only put between 9-10k per year so the recommended at least 1 per year is fine with me.

[carve]

Originally Posted by Radiation Joe

I change at 7500 mile intervals for peace of mind, but am sure, absolutely sure, that 15k miles is not a problem. Changing oil at the recommended intervals is better for the environment as well.

If you were "absolutely sure" you wouldn't change it 2x as often as needed. The only reason to do that is if you AREN'T absolutely sure. Your statement is self-refuting.

Chaning your oil is not bad for the environment (unless you dump it). If you recycle it, it's usually burned as fuel oil in industrial motors. It saves an equal volume of fuel oil. Environmentally, the question is whether it's better to have your old car last longer, or is it better for it to wear out to get one with the latest technology. Environmentally, that'd be tough to determine. Financially, it's still tough to figure out but probably a bit easier than the environmental figure. An engine that lasts a long time is probably more cost effective. Furthermore, an engine that runs WELL (good compression, etc.) for the vehicles life is more efficient AND better for the environment.

[Radiation Joe]

Originally Posted by carve

If you were "absolutely sure" you wouldn't change it 2x as often as needed. The only reason to do that is if you AREN'T absolutely sure. Your statement is self-refuting.

Chaning your oil is not bad for the environment (unless you dump it). If you recycle it, it's usually burned as fuel oil in industrial motors. It saves an equal volume of fuel oil. Environmentally, the question is whether it's better to have your old car last longer, or is it better for it to wear out to get one with the latest technology. Environmentally, that'd be tough to determine. Financially, it's still tough to figure out but probably a bit easier than the environmental figure. An engine that lasts a long time is probably more cost effective. Furthermore, an engine that runs WELL (good compression, etc.) for the vehicles life is more efficient AND better for the environment.

Ha!
I agree with your first point; I'm obviously not "absolutely sure". On the second point; more goes into an oil change than just switching the oil.

• The extra oil you use has to be refined and processed.

• It has to be packaged and that packaging disposed of.

• The old filter has to be disposed of.

• The contaminants in the recycled oil may contribute to additional wear in the engine which is recycling it.

[carve]

Originally Posted by Radiation Joe

Ha!
I agree with your first point; I'm obviously not "absolutely sure". On the second point; more goes into an oil change than just switching the oil.

• The extra oil you use has to be refined and processed.

• It has to be packaged and that packaging disposed of.

• The old filter has to be disposed of.

• The contaminants in the recycled oil may contribute to additional wear in the engine which is recycling it.

You got me on the packaging- you're right. If it's being recycled though, it offsets an equal amount of oil that now DOESN'T have to be refined and processed. The filter is probably going to cause a little harm, too (I always use a screwdriver to lift the flap and drain the oil out of mine), but collecting nasty stuff is what filters do, and you don't want that crap in the engine.

In the past, I heard recycled oil was burned as fuel in industrial diesel and heavy-fuel engines (e.g. generators, ships, etc.). However, I heard a rumour that some quick-lube places use actual recycled motor oil. Not so sure about this...If they totally re-refine it, it'd probably be fine, but someone using questionable quality oil probably isn't concerned with engine life anyway.

[stubenhocker]

I'm at 150, 000 miles on my 2000 E-46 cpe and I have only used scheduled maintenance, so far it has not used a single drop of oil or had any engine issues!

[JCtx]

To be this issue is like comparing the life expectancy of a fat and an athletic guy; both can live the same years, but which lifestyle do you prefer? Yeah, it's mostly a matter of preference . I prefer a mid-cycle oil change myself, and many oil analysis tests have determined it's best for the engine. Just like an active lifestyle is better than a sedentary one . Good day.

[foosh]

LOL . . . gotta love this age-old debate since the dawn of CBS indicators. In short, the CBS interval is perfectly fine, and doing is more often than the CBS interval is also perfectly fine. There is no evidence that one is associated with greater (or less) engine longevity than the other.

However, there is a benefit to doing it more often. It makes those owners happy and feeling like they're doing something good. That's worth something.

[John@BMW]

as a former BMW service advisor and long time BMW employee, I agree with the misinformation about bmw service intervals and how they are measured.

First off- your warranty ENDS at 50,000 miles. Your warranty period is from 0-49,999 miles. This means, if your motor blows at 50,000 technically BMW can tell you to take a hike. VERY unlikely but its possible!

CBS data is determined by MANY different factors. Yes there is an 'oil level sensing unit' that data is pulled from but also variables such as time, temperature, engine load, and mileage driven.

BMW does have a good amount of issues with corrupt cbs data and I have seen many customers come in at 30k miles for their first oil change because the cars CBS was WAAYYY off.

When I send my oil off occasionally to get it tested, they always come back that the castrol 10-60 oil is good for 4k to 6k miles- the bmw 5w30 for roughly 8k miles. That is just my results-

I have seen a lot of sludged motors from people who follow the normal oil intervals as per BMW.

on a side note- You ALL know about BMWs lifetime transmission fluid- You know that is BS, what about their "almost lifetime oil changes"?

[RealSanaii]

Originally Posted by John@BMW

as a former BMW service advisor and long time BMW employee, I agree with the misinformation about bmw service intervals and how they are measured.

First off- your warranty ENDS at 50,000 miles. Your warranty period is from 0-49,999 miles. This means, if your motor blows at 50,000 technically BMW can tell you to take a hike. VERY unlikely but its possible!

CBS data is determined by MANY different factors. Yes there is an 'oil level sensing unit' that data is pulled from but also variables such as time, temperature, engine load, and mileage driven.

BMW does have a good amount of issues with corrupt cbs data and I have seen many customers come in at 30k miles for their first oil change because the cars CBS was WAAYYY off.

When I send my oil off occasionally to get it tested, they always come back that the castrol 10-60 oil is good for 4k to 6k miles- the bmw 5w30 for roughly 8k miles. That is just my results-

I have seen a lot of sludged motors from people who follow the normal oil intervals as per BMW.

on a side note- You ALL know about BMWs lifetime transmission fluid- You know that is BS, what about their "almost lifetime oil changes"?

That's what my service advisor told me as well.

I put a thread regarding oil change price and people are still debating about this. I drive my car all year long and it's been about a year since my first service so it will be best for the car and my mind to change the oil in between the "recommended" service interval.

[lilalleykatt]

I have never blown an engine from changing the oil to often. Just 1 engine failure will set you back alot more than 5-10 extra oil changes.

[adamsm3]

Originally Posted by carve

No- the oil conditions SENSOR only measures conductivity. Read my post again. The other things, as I mentioned, are part of an algorithm that PREDICTS when the oil SHOULD BE degraded to some level considered unacceptable.

The CBS system does NOT just check the conductivity of the oil, it is also based on how the car is driven - short journeys, long journeys, engine temps, there is more to it than what people are guessing. CBS does extend or reduce the next service depending on how you drive the car i know this because i've seen it happen, when i bought a daily driver - a BMW 318 the service indicater was at 7k after a week the indicater increased to about 10k - i drive 1500 miles a week all on motorways.

[gr8000]

Originally Posted by John@BMW

on a side note- You ALL know about BMWs lifetime transmission fluid- You know that is BS...

No, I didn't know that this is BS - is it really?

[dynamite]

I can say that the CBS is totally B.S. After I had my first oil service at 2000 km CBS showed that 13000 KMs left for second oil service. Now I am at 5600 KM and its showing 8000 KMs left for the service. I visited the service and they reset the CBS nothing has changed. Service tech. advised me to change engine oil at every 10.000 KMs.
Now I am deciding to rely on my own CBS

Only parts to replace regularly is air filter, oil filter and engine oil.

First oil service at 10.000 KMs.

Second at 20.0000 KMs.

Third at 30.000 KMs.

and this will keep going on at 10.000 KM intervals. I will also change diff and transmission oil at every 30.000 KMs.

Nothing will hurt.