My just acquired 2004 XK8 had had green coolest used to top up, so I will be doing a power flush. A power flush to me means removing the thermostat a putting a garden hose in there. But I'm concerned that green may be traped in the heater coil. If I just turn heater on with car cold will the electric pump clear the coil or must I do something more sophisticated?

 

Be very careful with this.

There's a process, and it's very specific about not mixing coolants. It will gel, and clog the system.

See if this helps:

Flush and coolant refill:

https://cl.ly/hUAJ

 

I did a flush & fill using this procedure