Your Cooling System is Bleeding

Time for the new puzzler!

I have a great one. From my neighbor a while back.

We were talking about bleeding a heating system. He said to me, "Gee, you know, I've owned cars for about 100 years, and I have drained cooling systems, changed water pumps, put in thermostats... Done all kinds of other repairs to the cooling system of a car, and I've never heard of bleeding a cooling system. Of getting the air out."

Why do so many modern cars seem to need their cooling systems bled?

My first answer was something about destroying the rainforest... But I was just doing some footwork there to stall him because I truly didn't know!

So, the question is, how come some modern cars need their cooling systems bled?

And how come old cars never did?

Answer the Puzzler »

Remember last week's puzzler?

Scientific Headlight Experiments

Ready for the new puzzler.

A fellow is driving home from work in the late afternoon. And he notices that his car is not running particularly well. We can all empathize right away.

As he continues his drive, he notices it's getting darker and decides it's time to put on his headlights. When he turns on the headlights, he notices the car is running even worse. He begins to become concerned because it's running pretty badly and realizes he might not make it home in time for dinner, which is always a concern of mine!

So now, this guy decides to experiment a bit, being a scientific fellow. He turns the headlights off and the car runs much better.

Turning the headlights off improves how the car is running slightly. It runs noticeably better with the headlights off. And if he turns the headlights back on, it reverts to running poorly.

So, that's the puzzler. What's going on here?