Fresh water tank - Montana Owners Club

Mr Pachu · 10-17-2015, 01:26 PM

Does anyone else have this problem? We fill our fresh water tank up at home until water comes out the overflow. The gauge reads full. We then drive 80 miles to the lake and when we get there, the gauge only shows 2/3 or sometimes less. This is our 5th trailer and the only one that has had this problem. Dealer has checked the tank and there are no leaks. Any suggestions?

dieselguy · 10-17-2015, 01:57 PM

These tanks are pretty darned thin and the top bows down non uniformly. Each fill up offers a possible different air bubble around the top until the tank settles in from the weight of the water as you travel. Black and grey tank sensors are not too reliable although fresh water sensors usually read fairly close. Are you really short of water or just going by the gauge? We (2) can usually go 5 maybe 6 days on a tank taking navy showers and limiting the washing of dishes.

Mr Pachu · 10-18-2015, 05:34 PM

One time when we got to the lake the gauge showed 1/3 and we ran out of water the second day. Water was only used for washing dishes once per day, flushing the toilet, washing up in the morning and night but no showers at all. There are only 2 of us using the trailer.

**DQDick** · 10-19-2015, 02:26 AM

You might check to see if your overflow tube is disconnected. If so water would slop out as you drive. Never heard of it on a Montana, but I have heard of it on several Class A's.

thundercat · 10-19-2015, 04:48 AM

We have the same problem. It comes out the vent as you are going down the road. Thought of putting a back flow preventer in but then how would the tank vent.Took it back to Camping world where I bought it and they said it was the nature of the beast. Any suggestions would be appreciated.

Thundercat

1retired06 · 10-19-2015, 05:34 AM

That does not happen with our 2015, so doubt it is the nature of the beast as your dealer stated.

Mr Pachu · 10-19-2015, 12:50 PM

Our trailer is a 2015.

Recumbent · 10-19-2015, 01:59 PM

Possibly a leak in the fill line, it's the white hose that looks like a typical white water hose that runs from the back of the convenience center to the bottom of the freshwater tank. This water hose line is used to do a freshwater fill to the bottom of tank and retrieve the water for the pump when not hooked to city water. Since you have indicated there is no leak in the tank, then the fill hose line must be the next suspect. Also, try filling the tank and observed the ground and or black under cover for sags to locate possible leaks.

Mr Pachu · 10-19-2015, 02:19 PM

Recumbent, the dealer has done that. The dealer filled the tank until water came out the overflow and the gauge showed full. The trailer sat there for 5 days with no signs of a leak anywhere. The gauge still showed full and when they tried to put water into the tank, water came out the overflow right away.

thundercat · 10-19-2015, 06:18 PM

With ours when you go down the road you can see a trail of water coming from the convenience center. When you open the bay door you can see water coming from the vent pipe.

WeBeFulltime · 10-20-2015, 01:33 AM

Someone's "water thief" got away from them and is stealing your water! Sorry.....I couldn't help myself.

jcurtis934 · 10-20-2015, 04:10 AM

Since it doesn't leak out with just a tank fill, as noted by dealer, and it does when traveling...that rules out water leaking out the tank drain as an issue. Then the varible is movement. Assuming the dealer dropped the bottom of the monte and didn't see any leaks from anywhere while sitting still, that leaves you with the water slosh factor due to movement. It well could be that this is an issue being noted with tank movement and opening of a crack or worn spot on tank due to strapping. My fresh water tank looks like a sausage with straps that change its shape where there is a strap. I would fill the tank only half full and take a drive. The more possible explaination is opening of the tank output connection due to movement. That hose is held in place with a hose clamp. Undertightening it can expose a leak, overtightening it can also cause a leak since the tank fitting is plastic. And you have to understand that maybe the dealer didn't drop the plastic bottem to really check things out unless you witnessed it off. John

Hogfan · 10-20-2015, 02:54 PM

We have a 2014 Mountaineer 356tbf and last year on the first big trip when we would be boondocking, got to Sibley Lake in WY and our fresh water tank was down to a third. We took it back to the dealer and someone thought that it would be nice to put the overflow on the side of the tank. So far our dealer has placed an upside down p trap which didn't work. Next they put a restrictor on the tank. At the Montana Rally this was discussed with our service advisor since this is not acceptable if you are dry camping. It was approved by Montana to try to resolve this issue. It is currently at our dealer and they will be trying to lower the tank to put the overflow on the top where it should be. The problem is there is no room on top of the tank to put the overflow at present. You might check to see where your overflow valve is located.

Mr Pachu · 10-20-2015, 03:44 PM

Thanks Hogfan. I'll have the dealer check that out in the spring as the trailer is winterized and in storage right now. If the overflow tube is on the side of the tank, especially the back side, then it would probably fill with water when going up an incline and start a siphoning effect.

grumpylane · 09-11-2017, 12:37 PM

did anyone ever get the answer to this was the manufacture able to fix

cw3jason · 09-12-2017, 06:02 PM

Quote:

Originally Posted by grumpylane

did anyone ever get the answer to this was the manufacture able to fix

you cant fix water sloshing around and coming out the vent while traveling, it just happens

Mr Pachu · 09-12-2017, 07:27 PM

Quote:

Originally Posted by cw3jason

you cant fix water sloshing around and coming out the vent while traveling, it just happens

Our Montana was the only trailer we owned that lost water like that. A couple of trips with our Montana, the water tank went from full down to one third. Four previous trailers didn't loose water and our new SOB doesn't either.

Denny and Angie Miller · 09-13-2017, 04:06 PM

Would it be possible to somehow cap the vent, just for travel, then remove it when you reach your destination?

speedster100 · 09-13-2017, 04:53 PM

Well actually you can fix the water from coming out the vent while traveling by adding a ball valve or gate valve and closing it while travelling and then opening when you arrive at your boondocking location. I did this on a couple trailers I've owned, which were not Montana's.

I don't have an issue with the 3790RD so haven't installed one.

What the valve does is stop the siphoning loop that can start... The other thing you can do is put a plug in the vent if you can't get at the vent line with a valve, it will also stop the siphoning while travelling. You do have to make sure you open the vent line once you start using the water or it will likely suck your tank sides & top in...

cw3jason · 09-27-2017, 02:26 PM

I believe this happens on some of the Montana's like mine, because the fresh water tank is located in the back. those that have the fresh tank forward or mid ship probably have less issues.

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