After installing the dash knobs, I worked my way down to the front heater. The heating system is connected to the central engine cooling system, and this systems of tubes and radiators contains coolant fluid. It cools the engine in the first place, and if needed the warmed up coolant fluid can be used to warm up the interior by blowing air through the heater radiator which is placed underneath the dash.
The heater needed a serious fresh up; upper, lower part and handles were painted in the right colors, mounting hardware zinc plated, and fresh gray foam was used to restore the air valves. This way the front heater looks like new again! A very important job if you want to do a good restore, since its placed almost in your face. If you neglect this, you will be sorry after wards.
I connected all the hoses and pipes with factory hardware, working my way to the back, the rear heater. Later models are equipped with a rear heater placed in the mid console, in between the front seats. It has its own on/off knob for its ventilator and a sliding knob to control the heat flowing through the small radiator. The fan works independently from the front heater, but the “warm” button on the dash needs to be pulled out to open the main valve, so warm coolant fluid flows through all the interior pipes. Otherwise opening the sliding knob, wont change anything in the rear.
I choose not to disassemble the rear heater in the first place, the fan worked fine, the paint looked fair enough, and it will be covered by the mid console. Nobody but me will ever see the inside.
After connecting both heaters, I drove to the car parts supply shop, and got myself 7 Liters of standard blue coolant fluid. It had green fluid before, but I completely emptied the cooling system, so this will work just fine. After filling up, I was able to start the engine (never do this without coolant fluid!!!). This way the fluid pumps trough the sytem. You might want to open the warm knob on your dash to make sure the coolant fluid will run through the heating system as well.
Unfortunately I spotted a few drops of fluid on the floor pan, so I need to figure out later on where the small leak is located.