There are a few topics I would like to address
1) Not all SA's are created equal. Some SA's are just working a job and will say what ever BMW tells them. Some SA's are car people. My SA (who is also a friend) spends alot of time at the track racing bikes, though not cars, he still is a motorsport enthusiast. He is friends with the Techs which work on these car and he has shared with me many of the things they have said about what they see when BMW's are in the shop. There are many issues which we have discussed which the techs support which is different than what BMW officially states.
2) One big reason for auto manufactures have extended all of their fluid intervals is based on the EPA desire to have auto manufactures cut down on the amount of automotive waste. As we all know you cannot fight the EPA and this is one way the automakers can appease them. Yes, newer fluids are much better than what they were in the past which allow for longer intervals but BMW's intervals may be too extreme.
3) BMW is also in the business to sell cars. You cannot get a BMW transmission rebuilt, you have to buy a re-manufactured unit. If a person has a 6-7 year old BMW, the cost to replace a trans is 5k+. That repair cost is close to 25% of the value of the car. In many instances, an individual will just purchase a new(er) car instead of spending that kind of money on repairs. BMW benefits from this by moving more iron.
4) If you look at what BMW is now doing, you will see that they are decreasing their intervals on newer cars from 15k down to 10k. Why... They are experiencing issues with these long engine oil intervals. Any person who know engines would agree turbo engines are much harder on oils than a NA car. Look at the N63 Customer Satisfaction "sudo recall" campaign. Besides the replacing of parts not associated with fluids, one thing they are doing is testing the timing chains for stretch and reducing the oil intervals to 10k. There is evidence that the long oil cycles has been shown to cause damage to the timing chains. BMW would not be reducing the intervals across the board if this was not a much larger issue.
There has been many threads debating changing fluid at 1/2 intervals and there is usually two sides, 1) they do it because people feel it is better for their cars 2) How can a shade tree mechanic know more about fluids in BMW than BMW the company. Well this changing of the intervals shows that even the mighty BMW was wrong on this topic.
5) Another item which is effecting this fluid interval shorting in the North American market is due to the way we drive our cars. The BMW engine was not designed to run of short periods of time at low RPMs. This contributes to issues with the oil and oiling systems. It is well know that these short driving cycles where the oil is not brought up to temp has caused many issue. The clogging of the EGR valves and condensation building up in the oil had created many issues of sludge in these engines. Many BMW mechanics have stated that these cars need to have some High RPM's put them on a regular basis to keep everything flowing properly. By trudging along a city speed, stoplights and low RPMs do not do justice. Even look at the BMW charging systems. Those who have dealt with the "Increased Batter Discharge" knows all to well the BMW states that an unfavorable driving profile is created by short commutes and not extended driving. BMW's quest for higher MPG has forced them to not engage the alternator to charge the batter all the time which leads to the battery not being charged as much as it used to. This is just another point which correlates to the why we drive our BMW's is causing the problem.
6) If you look at how BMW designed the filter systems on the fuel and transmission, you will see that they don't want to replace them. This makes no sense. The fuel filter is part of the fuel pump which make is expensive to replace. The transmission filter is now part into the transmission pan and is not replaceable. If you want a new filter, you have to replace the pan. On top of that, the pan is now made of plastic. If you do have the service done, a new pan has to be ordered. The techs have said once you remove the plastic pan, 8 out of 10 times it will never seal properly again and it will leak. Lets say you didn't ever change the fluid, if the filter is not removing the contaminates, then what good is it.
I have had the trans and diff fluids changed on all of my past BMW's and every time the fluids are replaced, the tech always say that it needed to be changed. This was true on my 545, 550, X5 and M3. If the techs say the fluid looks bad a my 30-50K intervals, imagine what it looks like at higher intervals...
Ok my rant is done.
