I thought I heard a strange sound from the engine at start up. It was like a dentist drill and lasted about 10 seconds. Any thoughts?

 

probably your air pump which sounds better than the
bucket of bolts sound we have also at idle.

MK

 

I agree it's probably you air pump. It is a high pitched whisle that starts a few seconds after startup and goes away after about 10-15 seconds. It won't happen at every startup. And definatly will happen on a cold startup. If your wondering what it's for. It's an emissions device.