On the 80 300sd that I just purchased it had a shutoff valve between the engine block and the tube coming from the auxillary water pump. I have replaced the thermostat and coolant but I was not getting any increase in temp on the hose leading to the aux. pump. I know this has something to do with the climate control so I wanted to see if there was a blockage or if the valve was frozen shut. I used a thermo gun to see the different temps. When I reconnect3ed the hose without the valve there4 was no coolant flowing out so I assume this is where I mite have had a air pocket. I ran the engine and waited till the thermostat opened. Ther was no difference in temps from the hoses so I assume there is still air in the system. How mite one get the air out and why is nothing coming out of the dash in terms of heat or air.