First, real mechanics should not be confused with “grease monkeys.”
Mechanics who work for general (and chain) repair shops typically do not have access to any of the service bulletins issued by automobile manufacturers. These bulletins are not distributed to general repair shops in order to protect the dealer’s interests. Service bulletins are not to be confused with general service manuals.
Mechanics in general repair shops typically do not have access to many of the specialized tools required to accomplish specific repairs. In fact, they often do not know such tools even exist, again because the manufacturers do not make such items public knowlege. Plus, each manufacturer has specialized tools unique to a specific car–specialized Ford tools probably are useless in a Toyota shop. No general repair shop could possibly afford all the available specialized tools.
The fees associated with doing business as a general repair shop are horrendous, according to some people I have talked with. If a shop sells tires, disposing of old ones is a very expensive business. The same applies to old batteries and oil. Batteries in particular are considered to be hazardous and rigorous controls are imposed on the shop. The cost of diagnostic, brake, front-end and air conditioning equipment is significant.
Mechanics are required to furnish their own hand tools and the cost involved is substantial. Mechanics are often paid, even in dealerships, on a “flat-rate” basis, which is comparable to working on a commision only pay system. If the shop does not attract repair jobs, the mechanic does not get paid. When the mechanic is assigned a job, it is to his and the shop’s interest to accomplish the repair in the fastest possible way. This often involves the “shotgun” approach—replace everything that could possibly cause the customer’s problem. A contributing factor to this practice is the typical customer’s unwillingness to pay for diagnostic services or time.
The cards are stacked against mechanics in general repair shops but they are kept in business because people are unwilling to pay the price of dealership repairs. I have worked in both environments and have even owned a general repair shop, specializing in Volkswagen repair. Even with the best of intentions, I had to consider that my best information was at least two years out of date.
My advice is to always patronize the dealer.