Hi Paul,

A good idea that most ignore is to fill the cylinder head and block also. Most people install the thermostat housing and then fill via the expansion tank, which will certainly leave air in the system. Drain the coolant via the draincock on the right-hand side of the block. When refilling, remove the thermostat and fill the block and head (until it is completely full). Then, install a new thermostat (I would not use anything but a genuine Volvo thermostat, since they regulate temp so well). Once the housing is reinstalled, fill the expansion tank. Another thing that I would recommend is to replace the cap, since it is likely original (gray). They aren't too expensive ($15-20 at the dealer; the new one is green), and if they fail can lead to an overheating situation. The others mantioned some good points also, such as running the heat at full output to see if it gets warm. Anyway, if done this way, you shouldn't have any air in the system when finished (I have never had any air in these RWD 4-cylinders when using this method).

Good Luck,

Joe S. - Volvo Master Technician

2000 S70 AWD, 1981 242 Turbo w/intercooler