Thanks a lot guys!
Well I think that I probably have air trapped in my system, I will try to get the air out, and report back with the results.
When I refilled the cooling system, it took only 1 and 3/4 gallon of coolant/water to fill it up. I think the cooling system in a 300E holds 9.6 liters(more than 2 gallons).
1987 mercedes 300E
1995 e320 conversion(hated the 300e grill)
Monochromatic Paint (Custom Blue)
Flat Badged (front)
custom "carbon fiber" console
18 inch HP EVO rims
Sold! Now I drive a Monte Carlo SS