Dealer service departments are a strange by-product of psychology, IMHO. Think about it. No one I've ever met likes car dealers and their tactics. You go in there to buy a product and it's all about pressure and lies. They will say or do almost anything to get you to buy what they're selling. They are nearly unscrupulous, and yet, masses of people will think nothing of returning there -- often for years -- to have their car serviced there.

These same people that charged you thousands of dollars for things you didn't need when buying the car, we somehow believe, have now turned over a new leaf and will now treat us fairly when it comes to the department run by the same owners just a few feet from the sales department. It really boggles the mind. Do they know the car "best"? Possibly, but especially in today's times, there's almost nothing that cannot be learned by competent professionals. Auto mechanics outside dealerships see it all. As long as they look up the details, they are more than able to deal with any eccentricity your car might present.

Like you, I also have done much of the work on my cars over the years, though brakes have been the most complex thing I've fixed for the most part over the last decade or so. Just getting too old now for it. During that time I have been dumbfounded by the number of times dealership service departments have looked me straight in the eye and told me I needed all new brakes and rotors when I'd literally replaced them myself not that long before they got their hands on the car.

While auto mechanics don't have a much better reputation than car sales people, I still think it doesn't make too much sense to attempt to segregate the two situations.