This may be a dumb sounding question but where do you top up the water on a 71 spider? Direct in the rad? or in the expansion tank? also where is the level taken from? Should I see water in the rad when the lid is removed?
Yes. You should see coolant when removing the radiator cap. Never use just water in an Alfa engine. Use a 50/50 mix of antifreeze and water. Fill the system from there, then fill the expansion tank.
That said, if the level is down (or flushing and refilling the system), you need to bleed the air out of the system (bleed only when the engine is cold). There are two bleed screws, one on the top of the water pump, and the other on the top of the intake manifold. If you do not bleed the system, you can get air pockets in the engine that can cause overheating. Important, also, is the thermostat. It should be working properly and be a 180-185F model on a Spica engine. DO NOT remove the thermostat in an attempt to cure a overheating problem. That will just make it worse. Coolant will circulate too rapidly to be cooled in the radiator before returning to the engine.
Thanks.. thats a great help... My car is a carb model, does it still have the two bleed valves? I am planning on replacing the carb mounts so the whole system needs drained then refilled. Would you suggest flushing the system too?
Also, it appears that my car does not have a thermo fitted? Any reason as to why it would be missing?
Look for a brass screw in plug on top of the manifold.
The thermostat was probably removed by a knucklehead previous owner who removed it thinking it would fix an overheating condition. It doesn't. It usually makes it worse. Clean the radiator and make sure the fan is pulling air through the radiator. Also, the fan shroud is very important because if forces the air to come through the radiator instead of the sides of the fan.
I'd go ahead and flush the system while it's open and easy to do.