Replacing Dashboard Heater Core

Sounds like the Volvo dealer has been getting to close or living in a vacuum.... lol

 

I don't know about your specific model. Whenever I have drained fluid for repairs. I have changed the entire bunk heater, Front radiator, misc. hoses. thermostats. I never worried about a air bubble in the system. Most trucks I have worked on had shutoff valves for the front heater and the bunk heater. Just flip them off and drain the heater core. Refill your overfill tank or the radiator directly. Heat the motor to operating temp. Let it run about 30 minutes. Let cool check fluid add as needed.

I may be wrong but I think this dealer is trying to get a little work from you. Call a different dealer for another opinion.
Good luck.

 

I've done same thing on my ISX. And now every now and then I get very little heat till I crank it way high. And then I get too much. Do it yourself and then have dealer drain and refill it.

 

has nothing to do with "dealer drain and refill" you have a bad heater control valve. they are made of plastic and stop opening and closing properly internally. your increased flow rate is controlling how much heat you are getting instead of the valve controlling it. good luck.

 

They are puling your leg. You can actually get clamps and clamp the silicone hoses that run to the heater core.. and drain it right there.. and then refill it after you are done.. Most trucks have a self bleeding system.