The point...

Just as a clarification dearest Puppy Guts... It was not a matter of my volunteering your services because the car was broken. It was a matter of the car being broken with the chance of it having some kind of catastrophic failure, with the possibility of the children being in said car when that happened. If for nothing else, think of it as such. Whether owner of said car was or was not going to pay an exorbitant amount of money out of pocket is neither here nor there, but considering the amount the car owner would have had to pay? Seriously? I don't think so. I respect that mechanics have skills that some may not possess. Being able to bend a wrench is not something everyone can do. I get it. But seriously? That quote was ridiculous. I would have been quite miffed at you if  you had stood back and watched the mechanics take that money for something that you could have spent a little time doing.
If for nothing else, I volunteered your skills as a mechanic to fix a problem that would have caused something more than a minor malfunction and was something that needed to be fixed sooner rather than later. I wasn't saying fix ALL of the problems with the car. Whether the car gets great gas mileage is inconsequential.  I was merely suggesting that you fix the problem that could have led to the possibility of a catastrophic failure when the children could have been in the car. That Murphy guy has a pretty nasty sense of humor and his law is a real bitch sometimes. Unacceptable... Thank you for seeing reason in that and being so amenable to doing the job.
I know that eventually you would have come to that conclusion on your own and going as far as fronting the money for the part, taking the time out of your day to make sure that the job was done right for no compensation for labor (although THAT would go without saying, no?) and getting it done sooner rather than later.
In the end your "services" were not needed, but the job DID get done, quickly and properly by a professional which should bring you peace of mind.If it wasn't going to be done by you, I suppose the second best thing is getting it done by a professional mechanic.
I know that sometimes you need to be given a different perspective on how to look at things and it's wonderful that you are so willing and able to see reason from a different angle. I promise it doesn't make you less of a stubborn guinea. Choosing battles may make you seem less combative, but leaves room to fight even more passionately when battle lines have to be drawn. You are a step closer to reaching a personal goal. I'm so proud of you! Your girl, always...