See post #2

Leave pressure cap - known as radiator cap to some off of the pressurized coolant tank. Start car after refilling with fresh coolant. Though it may not be necessary with this setup, I always turn on heater to max heat position and fan on low.
Let engine idle while it warms up. When temp gauge gets up to around 80C, blip the throttle a number of times. You might want to lay a rag over the opening of the pressurized coolant tank when you do this.
If you feel you have an air pocket, elevate the front of the car with a floor jack.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"