If I fill my water tank to the top it always starts to drain out of the overflow once I start driving wasting a few gallons of water until it stops. These few gallons of water can add up to enough water to wash a bunch of dishes, etc. I was told to add a coil of hose up on top of the tank so this may help prevent the so called siphon effect. Has anyone solved this problem. My 97 Adventurer would do the same thing.