The part in the G is A0005062564. Of course, being a G part, MB wants $$$ for it. I suspect that any "MB heater monovalve" will do the trick. It is plumbed so that coolant will flow around the heater and heater valve when the power is off. The monovalve is smaller than the hose diameter, so it reduces but does not eliminate heater function. When the power is on, it closes and forces all of the water to flow through the heater + heater valve. On the G, there is a microswitch that clicks this valve closed at about the halfway mark on the heater control slider.that'd be great if you could. The valve setup i have is meant for hydraulic systems where pressure differentials are high, so I don't think it will work too well with the small pressure differentials the cooling system works with.