The Radiator Cap Solution

I was having trouble with something I couldn't readily identify myself, so I took my car into the shop.
The mechanic looked at it a couple of minutes and said, "What you really need is the radiator cap solution."
"Oh?" I said, trying not to sound too confused. "Do you mean the radiator cap isn't holding enough pressure?"
"That's part of the problem" he said. "You need to lift the radiator cap and drive another car under it. Then the next day you can replace the radiator cap, and it should solve your problem."
Originally published November 12, 2003.