I'd say your thermostat is stuck open. This will allow coolant from the radiator to flow through the block and head before the engine is fully warmed up.

Normally, the Tstat stays closed until the coolant reaches the predetermined temperature. When closed, coolant only circulates through the engine and heater core, allowing faster warmup. Only when it opens does the radiator come into the circuit to shed excess heat.

Go to:
http://www.volvospeed.com/Repair/thermect.htm

for the complete skinny on replacement of the tstat and ect sensor.
Good luck.
--
Erwin in Memphis, '95 855t