This topic's drifting from tech, but I'll have to leave it to the moderators to relocate it if they deem necessary.
You've dissed the previous owner, his car's techs, the radiator shop, and all Americans in general.
To which I can only reply, sequentially: with reason, with reason, with reason, and, well, okay, on the last of the four, my figuring that every single one of my fellow Americans is a thumbfingered idiot *is* a stretch, and it's unfair, and you're correct to chafe me about it.
However, I will say three things about the general run of incompetence in America.
The first is that it is very rare these days for me to have dealings with any sort of ordinary person practicing a trade, and then to come away from it with any sort of favorable impression. Auto work is just a subset of that. And no, it's not because I treat such people dismissively; I extend to them the same level of personal respect and courtesy that I'd expect were I doing their jobs.
This negative assessment includes tradesmen whose work I didn't contract for myself, and which I am merely surveying forensically after it has failed badly.
A friend of mine, a homeowner, has a bunch of shorted wiring from an inept electrician, a flooded yard from a plumber who cut corners installing her irrigation hookups, and HVAC ducting falling loose because the heating man didn't use proper duct mounts.
None of those were fly-by-night con artists; they were all apparently reputable, licensed and bonded professionals. But their work was junk.
Or, for an automotive example, when I pulled out the radiator, I found that the back face of the A/C condensor was trashed, with large areas of bent fins. This area is normally protected by the presence of the radiator. The most plausible way for those fins to get bent up is from someone ineptly removing, or clumsily reinstalling the rad, and bashing it into the condensor with considerable force. And then not fixing their error.
Am I incorrect in calling that unprofessional?
I don't find every encounter with a tradesman unpleasant. In the last couple of months, I have had two that were a positive joy. One was a machinist repairing a part that I had munged through inattention and fatigue, another was an electrician diagnosing a weird intermittent that eluded me.
Both guys had tools I don't have. But more to the point, both of them used those tools with exceptional discipline and skill, and both did a far better job than I could have done, even if I had access to the same kit.
Both were timely, followed instructions to the letter, stopped to ask questions where necessary, and indicated at the end of the job that they would stand by it if any trouble developed. And both of them charged me top dollar, and I was utterly delighted to pay it.
Second comment I have is that it's not just the classic trades. I am a software engineer by training, and you would not believe some of the incredibly crappy slipshod work I have seen passed off in that field. I have acquaintances who work in other professional capacities -- medicine, for instance -- and they tell stories of incompetence that would keep you awake late at night.
Third comment is that although I as an American have some license to complain about how things work in this country, I have heard similar things from foreigners.
A couple of years ago, long before I had a Benz in the household, I was in Germany and out drinking, and I met a young Daimler electrical engineer (this was in the good old days before they turned into the conglomerated monster of DaimlerChryslerFreightlinerWhoKnowsWhat AG).
He had just been on detached duty working in the field with MBUSA trying to slipstream a fix for some electronics that had gone out in poor shape. But the experience of six months Stateside working with Americans had shaken him.
His comment was: "America! (long pause) America. (long pause) Does anyone in your country ever read the printed instructions?"
Apparently the bulletins from his department regarding the bad circuit boards had been read and complied with faithfully everywhere in the global Daimler empire except for, you guessed it, the USA.
And to judge from what I read in the comments section here about horrible experiences with contemporary Mercedes dealer service departments, things have only gotten worse since then.