Community Forums

OwensKa1a · 11-09-2021, 08:40 AM

When I bought my RV the seller added water so that we could prove that everything worked...pump, water heater, toilet, faucets...

Yesterday, for the first time, I attempted to FILL the tank. Somewhere around half full (or before) I realized there was a SIGNIFICANT leak underneath. So I need to deal with it.

I see there are some DIY videos out there but this does not seem like something I can reasonably address myself. First of all, the only way I could see it being possible to get to/identify the source leak would be to use the leveling jacks to get the rig in the air. I'm pretty sure that would be considered recklessly unsafe. Then I thought I could get some super heavy duty jack stands to make it more reasonably safe. I haven't shopped them but I'm assuming they wouldn't be cheap and I wouldn't want to carry them with me anyway. So...I'm assuming my only real option is to take it to the shop.

I had my initial service (fluids and a couple other things) done at a local Cummins shop. They may do this work as well, not sure. But I do have a couple of Freightliner/Truck shops (Wolverine) nearby and I'm thinking that may be my best option. Before calling to make an appointment I wanted to reach out here for some wisdom on the topic.

Any advice on what I should do/check before heading to the shop?
Should I brace myself for a huge bill for this service? Terrified of that.
Any advice/insights would be appreciated.

Argosy · 11-09-2021, 09:10 AM

Are you sure it's a leak not an open drain valve? Put more water in it, turn on the pump, and see where it's 'leaking'. It it's coming out of a hose, it's low point drains or the fresh water drain. If it's through the floor or someplace there shouldn't be water, it's a leak.

153stars · 11-09-2021, 11:11 AM

Most RV water tank gauges are iffy at best. They have over flow/ vent to hose out the floor. If there is a "pretty rare" gravity fill port , owners have posted ,fill hose is on the side of tank " not great idea" and hose is no good.

**Lt Dan** · 11-09-2021, 12:03 PM

I seriously doubt Freightliner will service a fresh water tank as that's the coach builder installation, not theirs. If you can't investigate it yourself, then a RV service tech is your best bet. As suggested, make sure first it's not the tank overflow or drain valve.

Ljwt330 · 11-09-2021, 12:10 PM

It is important to let us know how you know the level of water in your tank. As mentioned, gauges are notoriously inaccurate.

Drain you tank completely. Get a cheap digital flow gauge at your hardware store and attach it to your fill hose. Research the volume of your tank. Then, begin the fill process and note when the leaking occurs and how much water has been used.

windsorbill · 11-09-2021, 02:16 PM

instead of expensive jack stands you'll seldom use, make up some ramps out of 2x12's attached together. Bottom board about 4' long. Next one about 3'6" long, next 3' etc. chock the tires with e-brake on before you go under.

That should give you enough room to slide under.

OwensKa1a · 11-25-2021, 04:48 AM

Quote:

Originally Posted by Lt Dan

I seriously doubt Freightliner will service a fresh water tank as that's the coach builder installation, not theirs. If you can't investigate it yourself, then a RV service tech is your best bet. As suggested, make sure first it's not the tank overflow or drain valve.

An update to the water leak problem. I knowledgeable friend came by to check it out for me. My (80 gal) tank is mounted above the diesel tank. Apparently there are 2 overflow hoses coming off (near) the top of the tank. I was reading the inaccurate/unreliable panel in my bathroom, which reads half full when the water started pouring out. However, we determined that the tank was full and it was simply the overflow hoses.

What astonished me was learning that the design of this overflow system is such that it can/will create a syphon effect and continue to SUCK water out of the tank once it starts overflowing. My friend simply held the hoses in the air and we could hear it break the syphon. So...the good news is I don't have a 'leak'. The bad news is those hoses are VERY inconvenient to get to and the idea of climbing under the rig and holding them upright to stop the syphoning is...ridiculous.

It turns out my friend had the same problem on his rig. He solved it by extending the hoses to an outside compartment where he added valves he uses to 'manage' the problem. I've read a bunch on this and (to my amazement) it seems a common design flaw in some rigs. One person solves the problem by opening his drain valve to break the syphon, then 'tops off' the tank after that.

What I didn't find was anyone trying what I intend to try. Specifically, if/when I 'overfill' and the syphon starts, can I not simply open a faucet/turn on the water pump to break the syphon? It 'feels' like the combination of gravity + water pump would be greater than the force of the syphon. But what do I know. Anyone tried this method?

Unfortunately my departure for warmer weather (I'm in Michigan) has been delayed a couple of weeks and the rig is now winterized for safety. So I can't do more testing until after I leave. I'll be getting a digital flow meter to aid in finding the right process. If all else fails I'll extend the hoses and add valves. But I have everything functional on the rig now (except the steps) so I'm a couple weeks from beginning a full time adventure.

blueridge-fl · 11-25-2021, 06:04 AM

If you search the forum, you will find people that have installed anti-siphon devices between the tank and the hose. The above suggestion about using a meter on your fill hose may be an easier and more practical suggestion. And you are right. Its a very common problem.

vseasport · 11-25-2021, 06:26 AM

Search siphon break. There are dozens on Amazon. One should be easy to install that will solve the problem.

mr.tommy · 11-25-2021, 11:15 AM

I don’t see this being a problem at all.
Just don’t fill it up to where the over flow problem kicks in.
You can fix this with a anti-siphon device or just leave it alone and just carry 1/3 to 1/2 tank of water with you.
Just don’t fill the tank all the way and use the flow meter Post 5 suggested when you fill the tank.
Now if your going to do a lot of boon docking where you want to carry as much water as you can, then yes it may be worth fixing it.

vseasport · 11-26-2021, 05:27 AM

Quote:

Originally Posted by mr.tommy

I don’t see this being a problem at all.
Just don’t fill it up to where the over flow problem kicks in.
You can fix this with a anti-siphon device or just leave it alone and just carry 1/3 to 1/2 tank of water with you.
Just don’t fill the tank all the way and use the flow meter Post 5 suggested when you fill the tank.
Now if your going to do a lot of boon docking where you want to carry as much water as you can, then yes it may be worth fixing it.

I was standing at a private landing strip one time. Watched a guy land his plane half way down the runway and hit the fence at the end. The guy next to me said every pilot should know you can't use the air space above you or the runway behind you. Just saying

Ljwt330 · 11-26-2021, 09:16 AM

The root cause of the problem is in the assembly of the overflow hose. A siphon will only be created if the tank end of the tube is in the water. Once the water level drops below the end of the tube, siphon breaks. What this means is the manufacturer inserted the end of the overflow tube too far into the tank. There is no reason why one should lose even one gallon of water, let alone 1/3 of a tank or more, due to a siphon.

If the overflow tube end, inside the tank, cannot be pulled up to a higher level, then the methods mentioned in these posts need to be employed. You cannot break the siphon by opening a faucet or using the water pump, it will continue to drain the tank until the water level drops below the end of the submerged tube.

THenne1713 · 11-26-2021, 11:42 PM

Suspect (most) overflows do NOT have a tube inside the tank, but simply a threaded fitting w/ an elbow w/ barb fitting screwed in, and vent hose attached? NO siphon action there. I had a broken 1/2MPTx1/2-barb elbow that some PO had slapped PUTTY over; $2 fix to replace elbow. I also would be looking for an OPEN drain valve BEFORE GOING TO THE SHOP???

Ljwt330 · 11-27-2021, 12:53 PM

Quote:

Originally Posted by THenne1713

Suspect (most) overflows do NOT have a tube inside the tank, but simply a threaded fitting w/ an elbow w/ barb fitting screwed in, and vent hose attached? NO siphon action there. I had a broken 1/2MPTx1/2-barb elbow that some PO had slapped PUTTY over; $2 fix to replace elbow. I also would be looking for an OPEN drain valve BEFORE GOING TO THE SHOP???

I agree, but my comment was grounded in another thread in which the op lost 2/3 of his water through the overflow tube. (BTW, I questioned the amount claimed to be lost.)

In this thread, only the leak was noticed and not the amount of water lost. He discovered an inaccurate tank level indicator was the likely cause. I wouldn't doubt that his tank fitting is as you described, but, apparently, not all are like that.