7. Perpetually chasing down your problem
If your mechanic suspects part X will fix your problem, and it doesn’t, be very leery of any additional repairs. While we’re all human and mistakes do happen from time to time, you shouldn’t have to pay for that mistake. If you’re okay with this, it can be very easy for your mechanic to rack up a huge bill while changing every other part out in the vicinity.
8. Not grouping repairs when calculating labor
There are some parts, like the water pump, that aren’t always easy to get to, which means removing other parts to get to the one in question. If some of those other parts are old or showing obvious signs of wear, changing them out at the same time makes sense. What doesn’t make sense, though, is charging you again for the labor on that other part when it was already part of the procedure for the first piece.