white goop in coolant and a shot water pump

so i'm hoping this isn't the head gasket that went too, but i have a
'88 CRX Si, and after replacing the thermostat it started overheating.
the water pump had been showing signs of failure before - chirping, etc
- and now it has gone. but the part that scares me is the white crap in
the coolant, which must be engine oil. is there any other way for there
to be oil in the coolant with a dead water pump, but without the head
gasket failing? while troubleshooting, the exhaust was clear, and there
was no blue smoke, so i think the combustion chambers are still sealed.
thanks guys.

-pete