The Third Mechanic

New puzzler time again.

Here we go.

Several years ago, many many years ago actually, we discovered a nifty way for detecting blown cylinder head gaskets. We used to use a dye that would change color when you remove the vapors out of the cooling system through the radiator cap. When you take the radiator cap off, we discovered that we could pick up those same vapors with our emissions tester, and in fact check for the presence of hydrocarbons in the coolant.

So you take the radiator cap off and get the engine up to operating temperature and you'd bring the tester over and place it near the radiator and if the thing didn't read zero, you knew you had a problem.

The reason this works is that when you have a blown head gasket, the products of combustion are going right from the combustion chamber into the cooling system, and pretty soon after that they get to the radiator and then come out. And at that point, the machine that you use to test it can smell when this happens. We can't smell it, but the machine can.

So one time, one of our mechanics was doing this test on a car and he turns to another mechanic and he says, "This guy's in trouble. He's got a blown head gasket."

Another mechanic doing a tune up nearby hears them talking. He hears them say, "I can see he's got like 60 or 70 parts per million of hydrocarbons when I do the test at the radiator here."

And without even lifting his head, the third mechanic says to the first two, "I don't think so..."

So the puzzler is, what did the third mechanic know that allowed him to say, "I don't think so..." with such conviction?

Good luck.

Answer the Puzzler »

Remember last week's puzzler?

Fused Headlight

New puzzler time.

Okay, here we go.

This happened years ago in the middle of winter.

My neighbor Frank asked me to take his jalopy in for some repairs. His old Lincoln. He made a list of things he wanted done. He wanted a tune up, an oil change and check the brakes and put new belts on and replace the leaking valve cover gaskets. All the things you do.

And being neighbors, he didn't bring the car into the garage. He actually asked me to drive it in myself. So I did. And I did all the things on his car at the garage. Then that night, I am driving the car home to his house.

So while I was driving the car home, I stopped at a traffic light and I noticed something interesting. There was a light shining under the dashboard. In fact, it was lighting up my feet. And I thought it was interesting. It seemed like a courtesy cabin light or something.

So, I keep driving home because I know my wife is making this amazing, well thought out dinner, and I don't want to miss it. But I also want to know where this light is coming from. So, as I am driving, I lean down to try to glance under the dashboard. (Don't try this at home please!)

So what I see under the dashboard is in fact a headlight. A headlight that is somehow wired into the fuse box, under the dashboard of the car. I didn't notice it during the day, of course. But that night, it became clear there was a headlight under there.

So, I get home and I deliver the car to Frank. And when I get there, I hand over the keys and hand him the bill. And then I said, "Oh, by the way, I think there was something you wanted fixed that you forgot to tell me about, right?"

And he said, "Oh yes, you're right!"

So, what was the light doing under the dashboard? What was the purpose of the headlight that was wired into the fuse box under the dashboard?