detected some nasty rear heater leakage in my westy.... first I thought the
core was bad, and it does have a little rust on the bottom, but now I bench
pressure tested it somewhat and it seems for sure the seal next to the valve
is gone,  but saw no leakage from the core. of course a 5 min test does not
resemble a 1000 mile drive. makes me think whether the rust on the core is
just of the coolant running down and pooling up in the plastic case the core
sits in......
so do the heater cores typically go bad at all? am I safe just replacing the
valve?

thanks everyone
flo