2000 Chevrolet Impala. 3400 V6.
Question: On do we replace the o-ring on the intake the line from intake to heater.
Answer: Exactly which O-ring are you referring to? Are you talking about the O-ring on the pipe that is on top of the water pump
that goes to to the heater? Or the pipe on the lower intake manifold underneath the throttle and next to the thermostat?