Fresh Water Loss While Towing

ctechbob

ctechbob

Well-known member
Was informed this weekend by my friend that was following me in their rig that I lose a LOT of water out my overflow when I'm towing with a full fresh tank. Sure enough, when I checked when we got to the campsite, I was down to 2/3rds full. (Same thing happened on the reverse trip.) We had started with a completely full tank.

Already ordered a small valve to shut off the overflow after filling. Glad we were paying attention. Would suck to set off on a long trip that we were going to be relying on the freshwater tank for.

I've started towing with a full tank in preparation for longer trips when we will need it. Mainly to confirm trailer handling/braking and the like with the additional liquid weight on board.

Apparently this is not an isolated problem. When I got home I fired up the Google to see this:

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We'll see if the valve solves it. Can't see why it wouldn't and also don't see why I can't seal off that overflow when I'm not filling. The tank should be able to get plenty of venting through the fill cap. It isn't sealed in any way and air should be able to go right on through.
 
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ctechbob said:
We'll see if the valve solves it. Can't see why it wouldn't and also don't see why I can't seal off that overflow when I'm not filling. The tank should be able to get plenty of venting through the fill cap. It isn't sealed in any way and air should be able to go right on through.
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I agree. The only time the fill cap won't vent fast enough is when you are filling.

We tow with a full tank (100 gallons) regularly, because we either need the water for the long trip and are not sure we will stay at a full hookups park along the way or we need the water when we get to our destination. We don't dribble water along the way.

I'm curious if you can see the routing of your vent?
 
Azjeff said:
Drive smooooth and miss the potholes. 🤘

I don't remember seeing an overflow tube under the trailer.
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I think all FWT's have a overflow... on mine it is just 2 small elbows in the frame area... so the overflow may not be easily seen, but it will evidence itself if you just keep filling the tank to the point of capacity..
 
ctechbob said:
Was informed this weekend by my friend that was following me in their rig that I lose a LOT of water out my overflow when I'm towing with a full fresh tank. Sure enough, when I checked when we got to the campsite, I was down to 2/3rds full. (Same thing happened on the reverse trip.) We had started with a completely full tank.

Already ordered a small valve to shut off the overflow after filling. Glad we were paying attention. Would suck to set off on a long trip that we were going to be relying on the freshwater tank for.

I've started towing with a full tank in preparation for longer trips when we will need it. Mainly to confirm trailer handling/braking and the like with the additional liquid weight on board.

Apparently this is not an isolated problem. When I got home I fired up the Google to see this:

View attachment 3002

We'll see if the valve solves it. Can't see why it wouldn't and also don't see why I can't seal off that overflow when I'm not filling. The tank should be able to get plenty of venting through the fill cap. It isn't sealed in any way and air should be able to go right on through.
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ctech, I don't think you lose very much water out of the overflows... a couple gallons at most.. those friggin LED's are useless on the tanks... because I've filled mine to the point of overflowing out of the drains and LED says I am full, and I drove it a bit and it said I was 2/3.. I think you are overthinking it.. not too mention how hard is it to add water if you really need it...
 
MSCH said:
ctech, I don't think you lose very much water out of the overflows... a couple gallons at most.. those friggin LED's are useless on the tanks... because I've filled mine to the point of overflowing out of the drains and LED says I am full, and I drove it a bit and it said I was 2/3.. I think you are overthinking it.. not too mention how hard is it to add water if you really need it...
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According to my friend that was following me, I pretty much lost water the whole way on the 2 hour drive. She was behind me and said that she saw water leaving almost the entire time, especially during turns and braking.
 
Before and after. Probably going to go back and trim some off the hose and maybe put a clamp on it. It was hot, and I had other things to do today that needed my attention. Should work just fine, not a rocket science fix by any stretch of the imagination.

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Wayne said:
Let us know how much water you don't lose next tow.
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Yep, we're out again next weekend, same friends will be following us and I'm the navigator again so I'll report back.

If I'm still losing water, I'll be in trouble....and angry.
 
Yeah ours does the same thing. Problem is the vents are on top of the tank and don’t extend far enough to put a valve. There’s 3 hoses and not sure what is what. Going to drop the tank in October and try to set something up. I’d like to extend the hoses up to the valves and back down.. I’m liable to forget otherwise!
 
esmith2039 said:
Yeah ours does the same thing. Problem is the vents are on top of the tank and don’t extend far enough to put a valve. There’s 3 hoses and not sure what is what. Going to drop the tank in October and try to set something up. I’d like to extend the hoses up to the valves and back down.. I’m liable to forget otherwise!
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If you fill your tank and it starts running out the overflow, can you not get to that hose? That's where I put my valve.
 
ctechbob said:
If you fill your tank and it starts running out the overflow, can you not get to that hose? That's where I put my valve.
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No its wedged between the tank and frame. It would be a dirty nightmare every time. Anymore I just do 2/3 and fill it sooner.
 
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