Water splashes out overflow while driving

[Aspect27Guy]

My water tank was full when I left home and by the time I parked in the mountains an hour's drive away and set up, my tank was at 1/3 full!! Along the highway around curves I could occasionally see in my side mirror water splashing out the overflow port on the driver's side (Winnebago Aspect 27), but I never imagined I could lose so much water while driving.

It would seem the overflow tube opening should have a seal or plug to keep this from happening. I note the rubber flap seal on the inside of the little door that closes against it, but it obviously isn't a tight seal. I could stuff a rag in the tube or something simple and low-tech, but just wondered if anyone else has experienced and fixed this issue.

This is my first motorhome and am the 2nd owner, so I am an anxious-to-learn newbie.

[Morich]

What year will be an important point but I suspect you are talking about the gravity fill port, rather than an overflow?

[Aspect27Guy]

Originally Posted by Morich

What year will be an important point but I suspect you are talking about the gravity fill port, rather than an overflow?

It is a 2015, and yes, I meant to say the overflow port on the side of the coach.

[Morich]

Did a little looking to see if there might be some part to slow the water backing out and it does look like a design defect from here!
There are actually three different models of the 2015 Aspect in 27 foot in case you have future questions, but two I looked at seem to have the gravity fill valve nearly even with the top of the tank and no provisions made to slow the water coming back on corners, etc. Both that I looked at say the tubing is 1 3/8 ID so my best plan might be to "invent " a stopper. Not a good plan but perhaps
better than arriving empty?
From there it might depend on what you have to work with. Super nice might be to let a techie sort build a plug with a printer to fit snug into the hole and add it to the door?
Maybe one of these in the correct size:
https://www.homedepot.com/p/NEXT-by-...0839/304016922
Sorry, I don't see any good options to repair so we need to invent?

[Goodspike]

Is that one thing looping upward in the bottom picture a vent hose? If so it seems as if they dealt with the issue for the small vent pipe but not the large fill pipe!

Something that compresses/expands with the twist of a knob would be perfect, as long as it couldn't generate too much force. Like a boat plug, but larger diameter.

[Morich]

It is the gravity fill so the input can't be run up and still get it to run into the tank.

[Aspect27Guy]

Thank you all for the quick reply and great ideas. I love this forum already.

[jrpend]

I'm not sure how relevant this is to your rig, but on my 2015 Itasca 37F, I was losing little under a third of the tank to a siphon through the overflow.


I could fill the tank by watching the water level, but as soon as I started driving around, water would go out the overflow, starting a siphon that would drain it down quite it bit.


I fixed it by putting a vent the overflow line at it highest point. Now I will still get overflow when the water is sloshing around, but the vent breaks the siphon so the tank stays very full

[Jdhargis]

My 2018 Vista LX does the same thing. It has happened multiple times. I finally found a plug I could put in it while traveling. I have to remove it when I'm hooked up at a park. Because sometimes the normal tank /fill tank valve valve leaks and allow water to fill my tank.

[JoeC]

May not be an easy fix but my guess would be that the overflow tube extends down too far into the tank and the sloshing action causes the tube to siphon the water out until it can no longer support the siphon. My Itasca Spirit has the same issue to a lesser degree, therefore not worth fixing. I don't bother filling until it starts flowing out the overflow anymore as it will just drains out on the road eventually. I may address this at a later date but for now, 2-3 gallons is not worth going after.

[NeilV]

The vent is needed to be open to prevent the tank from becoming vacuum locked. Higher routing of the drain hose would be the first simple fix followed by installing a vacuum break to prevent siphoning.

A physical plug that you would have to remember to remove at your destination and could hamper pump operation while in transit would be the last option to consider. You really do not want a vacuum in the tank developing sucking the top down and the sides in since that can lead to cracks and leaks.

A call to Winnebago Tech Support may get you a factory engineered fix and possibly at no charge if its due to installer error routing the vent at the factory.

[Jdhargis]

I have an 80 gallon tank and some days I lose 60 on a days drive.

[Nina]

Our coach started spilling out after many years of use. Dennis thinks I am nuts but I let a little spill out than fold it and clamp it with a chip bag sealer. I have only lost it once on the road.
Looks like another job for him to look at the venting.

[Goodspike]

I wonder if this is a sign they don't want you driving around with a full tank?

[NeilV]

Could just be the new techs assigned what should be the simple jobs and messing it up.

My 2001 Adventurer only loses water when I overfill it and even then the overflow tube is not sticking so far into the tank that it could draw over half the water out out of the tank. If I leave with 100 gallons of water I usually arrive with that only minus what it takes to flush the toilet and wash your hands a few times.

[Aspect27Guy]

I was able to find a $2 rubber tapered plug at a hardware store. I had to slice it down so that it does not stick out so I can close the small door. From some of the comments, I am noting the plug solution should only be a "while traveling" fix and I need to unplug it for venting to use water when parked. Is this correct?

[Morich]

It seems there is a lot of confusion about what the OP has. An overflow could be made to run up to avoid the problem he asked about. But what he has is not an overflow, although it can do that I would assume. What the specs list is a gravity fill and that can't be used if it goes UP!
If concerned about building a vacuum enough to crush the tank, I would first want to do some testing to see if that was possible on my specific RV and type of plug. If you do find it has no other point for air to enter, I would first look at making a small air gap on the edge of my plug. It doesn't need much gap to let air enter, so a small saw kerf would likely let enough air in but not let much water out if the kerf was at the top of the plug. At the speed the RV pump moves water, I would not worry too much as the plug probably is not totally air tight anyway.

[Aspect27Guy]

I called Customer Support and learned a bit. My coach (2015 Aspect 27ft) has the gravity fill on the side where I see the water splashing out of in my side mirror around corners, but I just don't think it could possibly be half a tank or more. There is also the overflow tubing at the top of the clean water tank underneath. He suggested looping that hose/tubing above the tank. I have not looked under there to see what I have, but I will be crawling under soon to check it out and create this loop to alleviate a possible siphoning effect if the overflow hose/tube just hangs down. This may require a longer length of hose/tubing.

He also confirmed that the plug in the gravity fill/overflow port on the side may help while travelling, but that it should be removed when parked for venting and pumping water to the sinks, showers, etc.

Thank you all for your thoughts and help. I hope this thread helps many who may experience the same issue.

[Morich]

Sounds reasonable that you might see the water at the side while far more water was going out a siphon but I still have some doubts. One is the size, I would expect to be used for overflow would be small tubing and I would not expect it to run very far down into the tank, both just as economy items. small tubing like 1/2 inch?? would not seem to be easy to keep filled as we cornered, stopped or started and if it is not filled full time, the siphon is broken until it gets full of water again. I do a lot of siphon with keeping fish tanks for breeding and it is not always that easy to keep a siphon running. Getting one running and then keeping it running seems to far for me to fully think that is the major problem. But one thing that would change my mind was if you drive for a bit and then stop to find the water running out on the ground!
Looking at making a loop is certainly worth the time but doing some watching may tell you something more also.
All these little points sure makes life interesting, right?

[Aspect27Guy]

Yes, interesting and educational. Thanks for the thoughts.