It never ceases to amaze me, so called "certified" (more like certifiable) mechanics don't seem to have a frigging clue about cars, BMW's in particular. It seems like the recent set of mechanic college grads have never even DRIVEN a car. They can diagnose a computer code, but if you throw them a more complex problem, they don't seem to apply common sense.
A great example is a recent problem my ex-boss had with his 2004 BMW 330 ZHP Package. He took it to the local independent BMW mechanic place and told them to change his oil and air filter. He also mentioned he was getting poor gas mileage and had a CEL. This CEL (check engine light) code was checked by me a few weeks earlier as p0174 and p0171 which are system lean codes. Anyway a few hours later he called to check the status of his car and they had blown up his DME (computer) trying to re-flash it with the latest software. Car was dead. The problem with this is two fold. 1. The never called him to ask if he wanted a re-flash in software. 2. It doesn't make sense why they tried that to begin with. (I will elaborate more why in a moment). Then they told him it would cost $800 for a new DME, but they wouldn't charge him labor. I called and found several used DME's for $250 locally, but why would they charge this guy for their mistake? Unbelievable! Back to my comment about why they didn't need to re-flash the software to begin with. The simple fact is that the car used to get 4mpg better gas mileage without the software reflash. So common sense tells me there is something mechanically wrong somewhere or else it would be getting the same mileage it always got. And while a newer version of software may have been available, it certainly wasn't needed to restore the car to original fuel mileage standards. Yet, as is so often the case, the new breed of mechanic has no idea how to diagnose a problem more complex than a computer telling them to replace an 02 sensor.
Another story I just recently heard was even more mind blowing. An owner and member of a BMW online forum had some issues with sluggishness in his 330i. He was thinking it sounded like a VANOS problem which is pretty reliable to think. He asked a "trusted mechanic" (his words) about it and was told "the E46 didn't have VANOS problems, that was more on the 5 series". WHAT!? I did a quick search on realoem.com and sure enough the part number for the E39 5 series VANOS and the part number for the E46 3 series VANOS are IDENTICAL! Meaning SAME EXACT PART! Now shouldn't a "trusted mechanic"/BMW expert know that? And in case that person is reading, yes you should replace your VANOS seals, and no you should not buy the Dr. VANOS kit, you should buy the Beisan Seals (only $60 here is the link) and have someone besides your "expert" install them.
To magnify this topic further, I (who found the VANOS part #'s in 5 minutes online) have zero hours in a ASE Certification school, no formal mechanic training, and no BMW training either. What I do have is 17 years of drag racing, trial and error, car repairs, and common sense (along with a decent mechanical aptitude) which has proven to save myself and countless people serious amounts of money. Am I an "expert"? I don't know about that. But what I do know is the
more I hear about what other so called "experts" are telling people (not to mention what they charge) and doing to people, I feel like a BMW genius.
In summary, I will tell you this. We live in the information age. Almost anything, ok ANYTHING, can be found on the internet if one dare look hard enough. BMW owners especially have multiple resources online. And tapping into the collective genius of an internet forum such as Bimmerfest.com is worth way more than you can imagine. Go to Autozone and have your codes read, don't be afraid to dig around under your hood, or log on to a forum and ask a question. As I have said so many times, "what one man can do, another can do!" and working on cars is no different! So you don't have to blindly accept ANYONE's opinion (not even mine) without digging a little deeper first. It might save you money, it might save you time, it might save you both.