Kiwinz
replacement of the under hood valve will go along way towards correcting your issues. I've seen these valves discussed here on stovebolt several times and considered going that way on my deluxe but wanted to go org, so went with new Ranco. I have seen valves like your underhood valve all over on amazon & ebay etc..... and they are reasonably priced & may be the best way to go in the long run.
Good luck
delky dave in wyo


1957, 3100, v8
2016 gmc 4wd