WHAT DIFFERS DOCTOR FROM A MECHANIC

A mechanic was removing the cylinder heads from the motor of a car when he spotted the famous heart surgeon in his shop, who was standing off to the side, waiting for the service manager to come to take a look at his car.

The mechanic shouted across the garage,"Hello Doctor!Please come over here for a minute". The famous surgeon, a bit surprised, walked over to the mechanic.

The mechanic straightened up, wiped his hands on a rag and asked argumentatively, "So doctor, look at this. I also open hearts, take valves out, grind them, put in new parts, and when I finish this will work as a new one. So how come you get the big money, when you and me is doing basically the same work ?".The doctor leaned over and whispered to the mechanic .



(Guess .... what doctor would have said ??).....



Please try to find out your own answer .......






Here is the answer .......






He said : "Try to do it when the engine is running".