My 93 240 is making an unusual noise when I start it up in the morning. The starter cranks quickly 3-4 times (typical) and just as the engine starts, there is a slight "clunk" from the front of the car. It only makes this sound the first time I start it each day. Subsequent starts are completely normal. This morning, I had my son start the car while I was looking under the hood. I could not hear the sound from that vantage point, but my son still heard it sitting inside the car.

Any thoughts?

Thanks!