I am finally tracking down some leaks in my hvac system on the 1982 GLF and found basically two things.  1) The heater core is trashed and luckily I was able to find one, though at a cost, at least that's taken care of.  2) The worse problem. The coolant control valve (petcock) was covered in corrosion and still leaks even after cleaning it up and putting it back together. It appears to be leaking from the gasket that surrounds the little shaft and the rubber feels pretty hard. Im not