The Volkswagen cooling system uses a purge tank. as such you have to add one to use the Golf radiator. There is no fill provisions on the radiator. The purge tank has a small line from the top of the radiator to let the air out of the system and a larger line that that goes into the lower radiator hose someware. I connected the purge tank outlet line into the heater hose that returns to the lower radiator hose. The Golf purge tank is a nice little round unit but uses a bracket that is welded into the Golf. I found that one of the Audi's, a 5000 IIRC has a purge tank that bolts on to a flat surface. The Audi tank is working for now but I plan on putting a Golf purge tank in when the battery is moved to the trunk.
The top hose connects to the top of the radiator. The VW radiators have a small hose connection right by the main inlet hose. The tank is pressurized in normal usage.
I've found that many of the Volvo's use a similar tank.
Picture 11 shows the top hose connection to the radiator.
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