<<My rear heater core sprung a leak. Anyone have a good complete unit?
It will be for my 86 Syncro 7-pass Vanagon. Please pmail me.
Ron>>

Now here's an item I wouldn't consider replacing with a used unit.
Along with the radiator or the front heater core.
Ya just don't know what your going to get.

It could be another leaker, or be plugged up, and you won't know until
your done with the job.

Spring for a new rear heater core, o-rings, and the valve.
It isn't all that expensive, and you'll be only doing the job once.
( Unless you want to be practising rear heater core replacement )