Hey Klaus,

I pulled the heater core, and found the source of the 'bang' I heard. Hopefully, you can see the images I posted to this message - the bottom of the heater core blew out - have you ever seen this before?

I then bypassed the heater hoses, and ran to car to operating temp - no leaks, have driven the car ten or so miles without incident, so hopefully I avoided a head gasket failure.

This doesn't explian the oil light coming on, but as I think about it when the heater core blew out, and the car filled with team/coolant, I think maybe it stalled - that is wy I remember seeing the oil light on. Guess I was a little overwhelmed at the moment...I was also driving in heavy, mid-town traffic in NYC, which added to stress of the situation!

I have a new core on order and will fix later in the week. I also plan on doing a compression test, just to check results.

thanks again for all of you help!
mark