Dometic toilet will not hold water?

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DieselJay

Well-known member
Joined
Mar 22, 2011
Posts
153
Location
Ct
The toilet in my 2011 keystone Cougar will not hold water for more than about 5 min.  I was winterizing my camper and put antifreeze in the toilet than came back a few min later and it was gone.  Is this something I should be concerned about?  If you put water in it will hold water long enough to go to the bathroom.  I know this is something with the gasket,  is this something that can be fixed?  If so how hard is it to fix myself?  Thanks for help.
 
You may just need to gently clean the valve/sealing surfaces. I had the same problem with mine after it sat unused for about 2 months. Has worked well ever since.
The valve is replaceable. Many RV sales/repair facilities will either have or can order parts.
Or you can search on-line with your Dometic Model number. Several sites pop up with a search.
 
Yes, I would be concerned.  This is how the odors from below are stopped from entering your living space.  It is a "lock" that needs to have liquid in it.  The Dometic model is unique in that the seal can be replaced from up above without doing anything complicated.  As stated, you could check on the warranty but you may find the seal is so cheap that you want to buy a couple and be prepared to fix them yourself as needed.  In our Thetford, when they sit for a long time, the seal can dry out. 
 
Mine is the same way the seal can be replaced from up top without removing anything on the toilet. The only reason I found this out was I knocked the seal out using a toilet brush and was really simple to put back in place...
 
I just got done doing a major rebulid on my dometic, Six years and it holds water with the original seals.

I did clean them while i had 'em out though.

In digging through my owner's manual bag.. I found the "Seal cleaning tool"  Just so you know.. It really was provided.

Different models however.. May not have it (mine is a 111, which is the mirror image of a 110)

This uses a 50 dollar ball type valve... The dang shaft that turns the ball broke,,, They only sell it as part of a "kit" which includes the ball.
My new... Home made shaft.. Is stainless steel, not nylon.
 
Thanks all, as for bringing it back to the dealer for warranty, my dealer is almost 3 hours away one way.  So if its a easy and not to costly I would just rather do it myself.  I'm the type of guy  that would rather do it myself (so I know it's done right) but as said if costly it will go back.  From all your posts it doesn't sound to hard or costly.
 
Toilet would not hold water.  The Original Seal in the toilet is #700340043.  This is obsolete and is replaced by Kit #385311462 according to Dometic.
There is quite a bit of differnce as the orignal has a hard plastic upper ring  that the Teflon lower seal 700340043 fits into.
The replacement has a soft Upper Rubber ring that the lower seal of the same diameter fits onto.
I installed the repalcement kit and no more leaking
 
I have a Dometic 310 that was doing the same thing. Followed at the manufacturers instructions, clean, bend down the seal, use hot water, would never last for more than a couple of weeks.
I ordered a new seal and was leaving for a long weekend.
Before i left i thought what the heck an put about a half a cup of baby oil in the toilet and let it sit.

I guess it softened up the seal. Going on two months and no more leaks.

If you have a Dometic 300 series model the seal is very easy to replace from the top, no disassemble required.
 
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