[Vwdiesel] Over Heating problem 86 Golf NA

[Libbybapa at wmconnect.com]

There is a flow reducer in the line from the radiator to the expansion tank.  
It is a little rubber plug with a hole in it that is about 1/16"  If that 
hole gets plugged with a freed bit of crud or a lump of gasket sealer it will 
stop the flow to the expansion tank.  It will also cause the engine to overheat.  
I had that happen once on an '86 jetta diesel, and since installed a clear, 
metal screen fuel filter in the line back to the expansion tank.  The filter 
will not plug with little pieces of yuck, and if it does get nasty, it is easy 
to change.  It is remarkable how much crud can float around in the coolant 
system.  It's worked fine for 6 years.

Andrew