First time posting so I hope I get this correct... 04 BRG/W MC R50 CVT... Have a P0128. My daughter uses the car for only a few miles each day and didn't notice the SES light. The car had lost about a 1/2 cup of coolant every week but the temperature gauge never went above half-way on the scale. From reading some of the posts I drained the coolant, replaced the thermostat housing, the thermostat, the expansion tank (looked grim), and the expansion hose. Following the instructions in the Bentley book I began the process of refilling the coolant. The engine never 'drew' the coolant from the expansion tank so I'm not sure what to do at this point. With the car idling and the interior heater turned on high the fan on low, the heater never generates hot air... at least not before the temperature gauge reaches maximum. In the off chance that there was air trapped on the heater core I opened that valve a few seconds... no result. I'm looking for ideas. I think that the thermostat is operating correctly (the coolant in the fill tube is 'gone' after each attempt). No strange sounds coming from the water pump (not that I'd know what to listen for). And the radiator fan does come on high speed (and I think on low but I'll check).