RAY: Hi. We're back. You're listening to Car Talk with us, Click and Clack, the Tappet Brothers, and we're here to talk about cars, car repair and, uh...and, uh, the answer to last week's fully automotive Puzzler.
TOM: It was about a Chevy, hunh? An old Chevy. I don't remember it. I honestly don't.
RAY: Actually, I didn't either until I looked at my notes here. Anyway, a few months or weeks ago--I don't know when this happened--one of my guys was under the hood of an old Chevy pickup truck trying to find a vacuum leak.
TOM: Ach!
RAY: Now, a vacuum leak is a hole somewhere which allows extra air to leak into the engine or get sucked into the engine. And since all the air that enters the engine should get in through the carburetor or the throttle body or some controlled mechanism, any air that comes in anywhere else is a vacuum leak, and therefore unwanted.
TOM: Yeah, because it disrupts...
RAY: It makes the engine...
TOM: Disrupts the fine balance.
RAY: The stoichiometry.
TOM: Oh, man! And it makes the engine run lousy too.
RAY: That too. Especially if the leak is big enough. And in this case it was, and the car would not run at all, and certainly wouldn't run at idle. And in this case, it was stalling every time you would take your foot off the gas. And that's the problem this thing had. Anyway, now, the way you find vacuum leaks is either you get lucky and hear a hissing, and you say, "Ah, there it is!"Or we use a wand that has a little nozzle at the end that shoots propane gas, and when the propane and the vacuum leak, meet...
TOM: What happens?
RAY: The propane gets sucked in with the air that's getting sucked in. It renders the mixture now correct, and the engine suddenly begins to run better. Then, you move to a different spot or the engine returns to its lousy performance, and you go back and forth, and you say, "Aha! That's it!"
TOM: Yeah.
RAY: So, there he is with the propane wand under the hood, and the leak is so big, I guess, or so evasive, that he can't seem to find it. So, in desperation, he throws the stuff down and shuts off the engine. Of course, I do, what? Walk away. I don't want to...
TOM: Don't want to be part of this.
RAY: I don't like to micromanage, you know what I mean? You fix the cars; I'll do something else.
TOM: That's right.
RAY: Call me if you need me. A few minutes later, I walk by, and he's doing something interesting. He's pulling off the spark-plug wires, and he's putting them back on--but on the wrong plugs.
TOM: Mmm?
RAY: I say, "What a knucklehead." I walk away again. Two minutes later, I hear him on the phone ordering the part he needs to fix the vacuum leak.
TOM: Wheew!
RAY: What did he do?
TOM: He put the plugs on the wrong...the spark-plug wires onto the wrong...
RAY: Yeah. He does this all the time, so I didn't think it was any big...
TOM: Yeah!
RAY: What he did by hooking up the spark-plug wires incorrectly and running the engine [was], he made it backfire through the intake manifold. And when that happens and you get combustion taking place in the manifold...
TOM: Ah! He saw a puff of smoke.
RAY: There you go. A puff of smoke. And he found the gasket that was blown.
TOM: Man!
RAY: That's where he saw the puff of smoke escape, and, boom! He ordered it, and nine hours later it was fixed.
TOM: Man, the flat-rate book gave you 21 hours to do that job, so you charged for 21 hours.
RAY: Absolutely.
TOM: That's the way it goes.
RAY: Yeah. And Ken's car has never run the same since.
TOM: Boy, that's very good!
RAY: Do we have a winner this week?
TOM: I don't know. I have to look through these little pieces of paper.
RAY: Well, I need to satisfy the people who have an automotive interest. I had to have an automotive Puzzler at least...
TOM: Once.
RAY: Once in the current Puzzler season.
TOM: We have a winner, and his name is Ron Juris from Saginaw, Michigan. And, Ron, for having your answer selected...
[ Car Talk Puzzler ]
