Losing a lot of water through overflow while driving?

[86Scotty]

I think you've got room under there to just raise it. Looking closely at your pics, and having just redone all my plumbing, I think you can just pull the drain pipe up from the floor until it is touching the bottom of the seat and stick a piece of wood under it or something to try and see if it helps. First, this is free and a simple test. Second, SMB just leaves those pipes through the floor loose. I would look under the van and see where it comes out. I'm betting you'll see 3-4 inches (at least) of pipe sticking through the floor, so you probably don't risk pulling it all the way through. Even if you do, it won't mess anything up. It is a rigid pipe so just push it back through. Just tug on it from up top and get it as high as you can and you will minimize if not completely stop the leakage. Prop it up with a stick of wood and go for a drive. I would at least try this before you start spending money on replumbing. I used tape on mine but it is right up against the side of the tank. I'll see if I can get a pic of what I mean, but mine is now under the van where the spare used to be, so not sure if I can get a decent pic of it due to the frame.

[daveb]

Originally Posted by schluchtenflitzer

Check valve is not a good idea because the overflow line works in both ways.
1-air out: while filling-and water out if it is full and you still try to fill it up > you need it only if you fill up with your city water hook up
Also the water will expand if you fill it in cold and then stay in the sun for a while > tank will blow up
2-air in: if you suck water out with your pump, and if the water cools down if the tempereatur drops down

Of course you can ignore point 1 but then you have to open the inside filler cap while hook up the city water. If you forget this only one time you damage the tank and have a lot of water in your van

Wonder what keeps bugs and debris from being sucked into the tank from outside? A filter? Obviously I've never paid much attention to how it operates.

[sbgrimm]

gcvt: I'm still trying to understand all the systems in our SMB that we've had for 5 months. This thread encouraged me to spend some quality time checking out the fresh water supply, plus the falling temps have got me to thinking it's time to winterize. I noticed our tank has the air relief plumbing make a big square loop on top of the tank before heading down to the drain. I drew an approximation of what we have on your picture and attached it. Don't know if that would solve your problem but it looks like it might help by making it harder for the water to splash out.

[BajaSportsmobile]

My 30 gal. tank is under the floor of the van and my vent tube goes all the way up inside my tail light housing and loops back down with a filter on it. I no longer lose water on steep off-road hills like I used to.

[gcvt]

Originally Posted by 86Scotty

I think you've got room under there to just raise it. Looking closely at your pics, and having just redone all my plumbing, I think you can just pull the drain pipe up from the floor until it is touching the bottom of the seat and stick a piece of wood under it or something to try and see if it helps. First, this is free and a simple test. Second, SMB just leaves those pipes through the floor loose. I would look under the van and see where it comes out. I'm betting you'll see 3-4 inches (at least) of pipe sticking through the floor, so you probably don't risk pulling it all the way through. Even if you do, it won't mess anything up. It is a rigid pipe so just push it back through. Just tug on it from up top and get it as high as you can and you will minimize if not completely stop the leakage. Prop it up with a stick of wood and go for a drive. I would at least try this before you start spending money on replumbing. I used tape on mine but it is right up against the side of the tank. I'll see if I can get a pic of what I mean, but mine is now under the van where the spare used to be, so not sure if I can get a decent pic of it due to the frame.

Well, that would be a very easy and free thing to try. I'll give it a shot tomorrow. There's a bunch of silicone where to overflow goes through the floor, but if this idea works, it'd be cheap to re-silicone it to seal it up and help keep it in place.

Originally Posted by sbgrimm

gcvt: I'm still trying to understand all the systems in our SMB that we've had for 5 months. This thread encouraged me to spend some quality time checking out the fresh water supply, plus the falling temps have got me to thinking it's time to winterize. I noticed our tank has the air relief plumbing make a big square loop on top of the tank before heading down to the drain. I drew an approximation of what we have on your picture and attached it. Don't know if that would solve your problem but it looks like it might help by making it harder for the water to splash out.

Definitely don't have the clearance to add any plumbing on top of the tank but it's a great idea!

[gcvt]

Originally Posted by daveb

Wonder what keeps bugs and debris from being sucked into the tank from outside? A filter? Obviously I've never paid much attention to how it operates.

Good question. Never thought about that. In my case, it's probably the seven gallons of water constantly flowing out while I'm driving that keeps things from entering the system

Seriously though, I'll be looking at that tomorrow when I'm messing around.

Originally Posted by BajaSportsmobile

My 30 gal. tank is under the floor of the van and my vent tube goes all the way up inside my tail light housing and loops back down with a filter on it. I no longer lose water on steep off-road hills like I used to.

Sounds like a nice setup. Must be nice to be able to carry that much water considering where you go. What kind of filter are we talking about here?

[rallypanam]

My thought, and I have no idea if such a thing exists... But what about a two way pressure valve that would open with more than a couple PSI... Otherwise stay closed. Does this thing exist?

[daveb]

Well I couldn't help remember this picture and really don't want anything crawling in there.

[REF]

If you've got an inch above your tank, Sbgrimm's drawing of the vent tube will solve your issues, you need to look at the drawing the right way, it doesn't stick up, it lays flat against your tank up top with a few 90* elbows making the bends at the corners of the tank. I would not put an inline check valve, 2 way or otherwise on your vent tube, you just need to get the vent tubing to have a loop above your tank. You could cut that tubing right before the 3rd 90*, rotate the stub so its vertical, so that it doubles back then hook it up from there through the floor. Or get some appropriately sized flexible tubing for the whole thing, clamp it on, make a few loops taped on top of the tank then fed through the floor.

[1der]

[quote="daveb"]Well I couldn't help remember this picture and really don't want anything crawling in there.

Really? Sunday morning before breakfast? Think I might be fasting the rest of today!