Enclosed Holding Tank Area Leak

[ricere]

I had a bad day yesterday. As I was under the coach performing maintenance, I noticed a couple of problems with it that could be costly. One of the problems is with the chassis that I have posted on another part of this forum.

The other problem I noticed is a deteriorated panel underneath the holding tank compartment loose in the front side. Upon further investigation, I pulled the aluminum panel down in front about 1/2 inch or so and noticedthe plywood above the panel was the consistency of a memory foam mattress pad. You could almost stick your finger through it. From the appearance of the plywood, there must be a leak in the holding tank area and it has been leaking for a long time. After that, I sealed up the panel opening with a good silicone caulk.

I now plan to remove the peg-board access to the holding tank area and try to determine the best path forward to find out what is leaking, fix the leak, and replace all the deteriorated parts to keep the coach in like new condition.

I hate leaks, but I REALLY hate a leak that takes years to show up.

Will probably need some technical help from Newmar on this one. Hopefully this is something I can do myself. UGH!!!

[Chickadee]

ricere:

Hi from Tama. Say, don't know what I'm talking about, but,....might the deteriorating plywood below the tanks be due to condensation forming on the exterior of the tanks due to warmer content inside and cooler, moist ambient air. Just curious if such a condition MIGHT be the reason vs. an actual leaking tank? FWIW.

Steve

[ricere]

Chickadee, you could very well be right. I never thought of that. The plywood that is deteriorated under the holding tanks was dry at the time I discovered it and we use our fresh water tank in cold weather a lot. I will investigate that and consider it a probable possibility. I hope this is the case.

If indeed condensate is the problem, then every motorcoach in service has this potential problem if the coach is used in cooler weather, and that is not a good thing.

["007"]

Just a thought in cooler weather the furnace maybe coming on heating your compartment area's. Also if cooler weather you would have cool water in tank which balances out.
If you have high humidity in FL. say and cold water in tank than its possible for condensation.
I have never seen this even in hot dog days in August in N.E.
Will look for something in search later.

[GaryKD]

Hi ricere,
This could be what you fear or it could be a problem in the plumbing joints. Guess what I'm trying to say is during disassembly, go slow. In my coach and I assume yours the fresh water tank is the lower of the three tanks. Grey and black water tanks are on top of the fresh water tank.

In a way it is too bad you have sealed the damaged area. Looking there could reveal when the leak starts again.

Once the peg board is removed, I'd:
1. Determine if there are any symptoms with the tanks as you found them.
2. Fill the fresh water tank and over 24 hours determine if there are any symptoms.
3. Fill the grey and black tanks and over 24 hours see if there are any symptoms.
4. Put the coach water system under pump or shore water pressure. Wait 24 hours and see if you can find any symptoms.

The point of the process is to do one thing at a time and see if you can find what is wrong.

Much good luck and please keep us posted.

[ricere]

Great news...After removing the pegboard exposing the holding tanks (gray water top rear, black water top front and fresh water on bottom) there are no leaks in the compartment. Everything is dry and solid in the holding tank compartment.

Apparently what I thought was rotten plywood was actually insulation over top of the deteriorated aluminum underbelly panel. Road debris must have deteriorated the panel and caused it to come loose around the edges and exposed the insulation. I can't figure out why that particular panel was damaged by road debris, but that has to be what happened.

Dummy me, I thought the exposed insulation was rotten plywood, when in reality the plywood is on top of the insulation. Since there are no leaks in the compartment, the problem must be all underneath.

All I really need to do is install some light angle steel around the bad panel edges, seal it and paint it. Should be good as new.

[Chickadee]

ricere:

GREAT NEWS !!...glad you had NO leaks. Sure is a mystery about that deteriorated underbelly aluminum panel. Can't even begin to guess what that's about. Anyway....No major cost or hassle related to the tanks. Good !!

Steve

["007"]

The aluminum panel may have been cut to size to short in width and vibration shifted out of frame its laying in, dropped and caught all the road grime and salts along with it.
Glad your tanks are fine they are wedge in compartments unusually pretty tight.

[GaryKD]

Hi ricere,
Congrats on the good news. Thanks for posting the update.

[ricere]

007, I believe you could be right. Thanks to all for the shared ideas.