overheating

the heater core could be clogged but what happens when you let the car run more. Does the expansion tank fill up and overflow? If you drive the car any lenght of time do you loose anti freeze and over heat? You can back flush the system. Drain the system and then back flush the system with water . Prestone had made a flush system that connects into the heater hose on the heater core line. or you can disconnect one of the hoses and back flush using a reguler garden hose. Make sure the engine is cold if you flush the sytem. If you are loosing coolant I would have the system pressure checked.

water pump impeller is probably broke off.

with the coolant circulating and not making a noise then I doubt if it is the pump impeller broken off. With no heat then would go with the clog in the heater core.

How do you know if there is circulation? How are you measuring pressure? A good way to tell if the waterpump impeller is broke is if you take the thermostat out and stick your finger in the whole and see if you can spin th impeller on the pump. If you can then it is broke. All the impellers I have had seen break never made any noise. A clogged heater core is easy to see if it is plugged up. Just put your hands on both hoses and see if they are both hot. If one is hot and the other is not then the heater core is plugged.

I don't disagree with stevew84, but if the water was not circulating to me the coolant would boil out from the heat of the engine, not just fill the resevoir from not circulating. Question when the car cools down is the resevoir empty or just low where it is suppose to be. stevew84 probably has more experience than me. When I was a vw mechanic it was back when they still had air cooled engines.

What you are talking about with the boiling from the reservoir bottle is why I think there is no circulation. That's what I am guessing when the person said that there is coolant coming from the reservoir bottle(it is just boiling over). All the VW's I see that overheat that fast are usually from either a headgasket or a lack of circulation. Surprised the person has not replied about has happened. Last beetle with an air-cooled engine I worked on was about 2 years ago. Had to do an valve adj. to it. Good times.