Frank,

I tried a few times to respond to you and list. I don't know if you received any but the responses were blocked from the list.

What you want to do is when the light comes on, without turning off the engine go back there and check the coolant level in the tank. The coolant could be getting pulled down. Turning off the engine will allow the coolant burp back up when the pump stops making things look OK.

There are a number of reasons VW chose the have the fully pressurized coolant system on the Vanagon with the overflow or recovery tank on the other side of the pressure cap. The single tank system does not have as much capacity for expansion and as there is always some air space it takes some time for the system to pressurize after start up. The coolant being under pressure is important for cooling parts of the engine that can quickly get hot such as the tops of the cylinders. The pressure maintains contact and prevents localized vaporization which also causes cylinder and head stud cavitation erosion. Not as much and issue for the cast iron motors.

Dennis