And these people always wanted top mechanical work for cheap.
Oh heck yeah! I was and am the sort of person who if something does not work or is broke I do my best to find out why. What is it supposed to do or not do? Then find out how to make it do or not do what it should. An eldurr in the congregation where I live had some issues with a vehicle. He knew I had done the same exact repair on my vehicle, so asked if I would do the work on his. Feeling generous I said I would. A $2,000.00 repair job IF the dealer had done it cost him less than $200.00 for parts. At least I got a "Thank you until you're better paid," and the expectation that I was now his "go to" mechanic for free work, even to the point of having to pay for his repair parts.
I put an end to that, in what was perhaps a less than kind way. I would "troubleshoot" his vehicle, suggest a repair that for some odd reason never fixed the issue, then conveniently be out of town so he had to take it to the dealer if he wanted to drive anywhere.
Now my regular answer when he wonders what might be wrong with his vehicle is that I don't kNOw, heavy on the NO part.