There should be no water coming out of the belly. If yours leaks when full then there has to be a leak. Probably near the vent when full. But it could be elsewhere. We had a galley tank leak only when 2/3 or more full. But the leak was a hairline crack near the dump valve at the bottom. Apparently it didn't open until there was enough weight in the tank. So, if you don't see a leak up high, continue the search over the remainder of the tank. Also check the dump pipe.
See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'03 3295RK
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4
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