My 85 300CD has the problem of heat for a moment, then ambient temp air. If you bypass the monovalve won't the coolant circulate unimpeded (and unregulated of course) through the core? What are the odds of the core packing up...mine doesn't leak, but I am really suspicious of a clogged tube...

__________________
...a man's gotta understand
his limitations...

83 300D 360 K (Big Blue)
85 300CD 250 K (Little Blue)