Written while drunk and without the aid of proofreading. For your pleasure...
Do you know how to spot a real technician from a "shade tree" mechanic? Are you sure about that? Allow me to explain the differences to you. So, hold onto my hand, let's jump down the rabbit hole together. If you're a regular follower here, you know what's coming. LOL.
To start off, do you know what a shade tree mechanic is? The term (for me) originates with the TNN series "Shadetree Mechanic" which aired in the 1990s. It was a show geared towards the "DIY" mechanic who was working on their own stuff. At first I found it interesting. Then, I saw an episode where the "technicians" were going to change a turbocharger on a Dodge truck. One of the hosts said something like "this turbo has been on for awhile so I'm going to spray some penetrating oil on the mounting nuts." *spritz, spritz* then he puts a wrench on the nuts and *creak* they come loose. The dude didn't even tug on the wrench. I instantly hollered "Bullshit!". It was a scene that left a whole lot of stuff out. They didn't show that they sprayed the nuts with panther piss over three days or they cut out the dude using a torch to put some heat on those turbo nuts. The show was intending to show the average person, who had no idea how their truck's engine worked, that they could repair things themselves. Sure. Great. Sells advertising. You think they gave one damn about the DIY person when they pulled on that wrench and the stud broke? Fuck no! Any professional tech can tell you about the jobs that come in where, obviously, some person had tried to do something themselves (like changing a turbo) and found one or two broken parts. In the turbo situation the truck would come to us with a complaint of "exhaust leak" or "engine makes a whistling noise". If you're one of those people, just admit that you broke the shit. We can tell. We'll have more respect for you if you own the fuck up. If you're not sure that you can do the job yourself or, at least, can take care of your own fuck ups, take the vehicle to a shop. If you broke a bolt off because you actually thought WD-40 worked, be prepared to spend a lot of money. If you would have just brought the thing to a professional you could have save a lot of money in labor by not making things worse. You have to decide what's more important to you. Pride or money.
Now, if you "know a guy" and mention that fact, us professionals are automatically going to give you shit or turn down the job. You see, if I hear the words "My mechanic friend of mine told me..." I'm going to instantly stop listening to the words coming out of you pie hole. If your mechanic friend was any good you wouldn't be talking to me. You're just a cheapskate trying to cut corners and are now paying the price. Neglect your vehicle and it will tell you to "Fuck off!"
Back in the day, before I became a truck tech, a typical problem was the "no start". Invariably, the cars owned by someone who was either a do-it-yourselfer or "knew a guy" came into the shop with one, or all, of the following. New starter, new battery or new alternator. Shall we break that down? Averaging the prices of those three components (lots of guesstimation here) from, say, Autozone (the DIY-shade tree store of choice) you, probably, would have spent $300 and a 12pk. of beer and still had a car that wouldn't start. Why would that happen? Well, it's because the "guy you know" doesn't quite grasp how to diagnose a no-start problem. They don't know how to quickly break the problem down into smaller categories from which to continue their diagnosis. Oh, "it's probably fouled spark plugs." More money down the drain. It's not the 1960s. There's a whole lot more that can cause a no-start than just "tune-up" shit. Did "your guy" even bother to differentiate between no-crank-no-start and crank-no-start? That's the first hurdle. Or, did your "guy who knows cars" just start throwing parts at it hoping something would happen?
What about the "brake job" your "guy" did? Chances are the shade-tree just threw new pads on and called it a "brake job". Did he (not being sexist, it's statistics) measure the brake rotor thickness? Did he bother to check if the rotors are warped (pulsation problem)? Probably not. Did you, perhaps, ignore that grinding noise for so long that the brake rotor actually broke and took out the caliper along with it? When your pal "fixes" the brakes, and you notice the problem is still there, give you a warranty repair? You probably got the nice, excuse driven, version of a middle finger. "You'll have to take it to a shop because I don't have the tool for..." as he walks off with your cash. And it's always cash.
So, despite whatever your "mechanic friend" did, or did not do, you wind up with me. And you bitch, moan, call me a crook, tell me I'm just trying to sell you parts you don't need because "my mechanic told me..." Here's what I have to say to you. "Go fuck yourself." Yes, there are crooked professionals out there. There's crooked fuckers in every field. Who do you trust? Do you trust your "mechanic friend" because he somehow managed to get your car fixed with his 110 piece Craftsman "mechanic's" tool kit? Do you believe what you read on "Just Answers" websites? Here is what you do.
When your car does something it's not supposed to do, you'll think about the people you know and, supposedly, trust. "Jerry is a mechanic. He restored that '69 Chevelle..." It's a '69 Chevelle which, most likely, doesn't run all that well. A '69 Chevelle is nowhere near as complex as a 2011 Impala. Ask him if he can tell you how a crank sensor works. Did you get "Uhhh, well it... the crank..." answer? Tell that guy that the engine missing on cylinder 4 (assuming you know that's the problem) and see what they do. You'll probably get a new set of spark plugs and coil packs (expensive). That "mechanic" friend probably won't even think to ask you some important questions. When was the last time you checked the oil level? Does the engine misfire all the time or only at certain road speeds? Your "mechanic" probably can't even imagine that you have ignored the engine's oil level to the point it got so low you wiped out a lobe on the camshaft. Or, perhaps, a valve spring is broken. But, you know, when you end up at a shop full of crooks they'll say your car needs a valve job because, of course, all shops are trying to fuck you.
I see you have some new tires. Oh, and those nice aluminum wheels are all scratched to fuck. What's that? The left front and right rear tires keep going flat? Your "mechanic" just changed the tires... You think there's a nail in the two tires that are going flat... Well, before I start work let's make a note of the wheel gouges and, if you would please, initial my comments regarding the gouges. Why? Because if I don't, you'll try to blame me for what your "hammer and chisel mechanic" fucked up. When "I have a 150 piece mechanic's tool kit from Harbor Freight" mechanic changed your tires, did he even consider the corrosion on the wheel to be a problem? Did he take the wire brush that came with his tool kit... Oh, they don't come with wire brushes... and clean off the corrosion? Did "Shade tree" bother to spray down the beads and valve stems after the fact to verify there wasn't a leak? No, of course he didn't. Because that's the kind of "service" you get for parts+$50 and beer. But it's my fault. I'm just a thief running a "racket" to steal your money. So, just take those leaking tires back to your "mechanic" and demand a warranty repair and/or your money (and beer) back. See what happens. You'll end up paying me to fix his fuck-ups. But you saved a lot of money, right? NOT!
Disclaimer: If your "mechanic friend" is actually a professional, we wouldn't be having this conversation. Professionals do side work. Not all of us, but some do. I have no interest in doing my day job on my own time. When asked I quote the shop rate of my day job. Conversation usually stops right there. I went to tech school, I read books and trade magazines non-stop, I've worked my ass off. Don't insult me by thinking I'll waste my precious little spare time for $20 and beer. Fuck off. Also, don't expect your accountant to fix your car. There's a huge difference between a "shade tree" and a professional. Any shade tree fucker can throw parts at a problem (and even get lucky sometimes) but it takes a professional to diagnose the problem with minimal damage. Would you trust a doctor who says "Well, the people on Yahoo Answers said..."?