Black Tank - Methane Gas Smell

[Rustic Eagle]

I'm stumped .

First time with any of my RV's that I developed a strong methane gas smell emitting into my TT (nasty)...., originating from around the toilet. What's interesting was the tank was emptied & flushed throughly two months prior, and the smell didn't start until I arrived at my boondocking destination last week. So at the campsite I .......,

* Checked the rooftop stink pipe, all clear.
* Checked all P-traps/vacuum breaker valves.
* No visible cracks around plastic toilet.
* Toilet bowl seal fine.
* No dead mice/nests.
* Purchased and installed a new flange gasket.
* Added about 1/3 water and chemicals.

The above tasks didn't work, so the next day I filled the tank about 2/3 thirds full, dumped in a couple buckets of water/Dawn mixture, hitched the TT back up and headed to a State Park 12 miles away for a dump/flush. No sign of any tank leaks under the TT at the dump station. Headed back to my boondocking site....., the smell persisted from around the toilet, but not as bad.

* Added some tape around the floor base of the toilet and a the hand flush handle ......, smell still noticeable.
* R&R the toilet again, installed another new flange seal, re-taped..., same gas oder problem.

Before heading home a few days later, I did another tank fill and dump/flush, still had the methane gas emitting from around the toilet. I wasn't using the toilet while boondocking.

Long story short, dropped the TT off at my local RV repair facility yesterday. He will do a detailed inspection of the tank checking for cracks, all pipe/flange/stink pipe connections, remove and inspect the assembly seam of the plastic two-part Thetford toilet, etc..

I'm also having the tech confirm that the stink pipe isn't extended to far down into the tank. As an added venting aid, going to have installed a roof product called the "360 Siphon Vent", can't hurt.



The 360 Siphon link: 360 Products Inc

I'll report back the RV tech findings in a couple of days.

Bob

[Camping Couple]

Hey Bob, if your 278FBS is similar to the floor plan of our 24FBS, is the vent pipe in the storage closet of your bathroom? Worth a look for a cracked/broken pipe or fitting. Also, grey water related maybe?

Mark

[arkhillbilly]

Had same methane gas smell past winter in Yuma. My flapper did not seal good (sealed to stop water), but still a small gap. The odor was coming from my black tank, thru the commode. Knock your head off as I stuck my head down into bowl, and if I opened the flapper, a loud rush of gas would come from tank. It finally went away after a few clean outs. I may have mixed diff type of black tank chemicals, but have never figured it out!

[TCNashville]

Shot in the dark here--make sure that none of the screws that hold the flange [the one the toilet mounts to on the floor] are stripped. I had that problem on my old Flagstaff and whenever I mounted the toilet, it lifted [pulled up] the floor flange enough to allow gas to escape.

[Rustic Eagle]

Camping Couple,

Unfortunately the stink pipe runs up an enclosed inner wall, but the RV tech was going to check the pipe for any compromises. Both the grey water tanks and associated hardware are good, and the tanks do not give off any odors.

Arkhillbilly,

I agree, that methane smell gets one's attention, and lingers as well. The first time I added some water to the tank through the toilet you could visibly see the gas vapor in the tank.

After everything I did, I could still detect a faint gas odor coming from around the lower back of the toilet and around the manual flush handle....., have to wait and see what the RV tech comes up with.

TCNASHVILLE,

I did in-fact check the floor base flange screws, all snug. The RV tech that he has seen cases where a hair line crack in the floor base flange can open upon tightening the toilet down, said he would check. They are al;so going to check the piping going from the floor base flange into the tank.

Thanks again for everyones feedback.

Bob

[norty1]

Please post the outcome. Hope he can find it and let you get back to boondocking.

[loracnh5]

I had the same problem in another trailer in order to get ride of the problem i wood fill the bowl to just about overflow then flush i was told that filled some type of trap ? but it worked I would have to repeat this every once in a while I was told this filed some sort of trap hope it woks for you

[edatlanta]

I had a methane smell in my 5'er a few weeks back. It set off my co/propane detector continuously. I thought the problem was my gray tank and no amount of flushing or chemicals stopped the smell. I finally figured out the smell was some critter that decided to die somewhere in the enclosed underbelly. It lasted about a week and then went away. I thought it was a holding tank smell, but it was not. After the smell stopped I wired the co/propane detector back up. I had cut the power from it so I could stand being in the unit. I did turn the propane off at the regulator when this detector was out of service.

[nunyadamn]

Had the same issue last year and part of this year. Seems to be gone now - for the most part. Last thing they finally found was the vent tube had fallen down into the tank, so once we started using it, it plugged the vent tube and the smell would come into the bathroom every time we flushed. We just got back from 18 days of camping and once the tank got more than 1/2 full, we had the same issue. I am going to have them fill the black tank and verify the vent pipe is still clear. My guess is it has fallen back down or was not adjusted high enough last time.

[Rustic Eagle]

Originally Posted by nunyadamn

snip.....Last thing they finally found was the vent tube had fallen down into the tank,.......snip

That will do it, but checked mine from the roof and seems to be place but the RV tech is going to confirm. My understanding is that Jayco (at least in 2005) had some kind of support sleeve on the top of the black tank that would only allow the stink pipe to set 1" into the tank..... we will see!

Originally Posted by edatlanta

snip...... I finally figured out the smell was some critter that decided to die somewhere in the enclosed underbelly......snip

I did find a small mouse nest in the back corner of a floor heating duct giving off that familiar dead mouse smell, but once cleaned out it was fine (found just before departing on trip). But then again, there is still that remote possibility that something could have met it's demise on top of the black tank near the toilet/tank piping below the floor....., still waiting for a call from my RV guy.

Bob

[bmet2000]

I had a 2010 Eagle that had a constant blank smell coming from the base of the toilet. And when the black tank was full it would leak into the underbelly and then leak out onto the ground. I took it back to the dealer at least 4 times and they always said it was fixed when I don't think they actually did anything (thanks Camptown RV). Finally I took it to Bill Plemmons and they instantly figured out that Jayco had drilled the hole too large in the black tank and the only fix was to replace the black tank. Getting one took months and we missed a lot of camping that summer. But when we got it back it was fixed right and we never had a black tank leak or smell again.

[Rustic Eagle]

Follow-up:

Received a call from the RV tech today and they determined that the smell was being emitted into the trailer from the toilet itself. The toilet is a Thetford two-piece plastic toilet and the seal between the two sub-pieces was the root cause. There was also a seal at the hand flush handle assembly that was allowing odor to escape as well. Replacement seals aren't available for this particular model toilet so I'm having a new toilet installed.

The tech stated that the black tank and floor mounting flange were fine, and that the fill/flushing trips that I did eliminated the initial source of the methane gas smell. He stated that there was still some residual odor within the underside of the toilet, but stated some mold and mildew was present as well.

Problem solved.

I will be interested in how effective that 360 Siphon product works once installed on the TT roof.

Bob

[arkhillbilly]

Bob, glad you found your problem. Again, wish I could figure out what happened with mine. There was a build up in the black tank, for when I flushed, A loud rush of (air/gas) came out. Something had caused the build up. Was hooked up to sewer, and drained tank at about 2/3. First, and only time to happen.

[clubhouse]

I am the most impressed you dropped off your TT on a Saturday during during the season and then got it looked at and diagnossed by the following Wed. Around here all the shops are very candid they won't be able to even look at for a week + during the summer season and repairs will take even longer.

[Rustic Eagle]

Clubhouse,

Yeah, and my BIL did better than me....; My BIL dropped his TT off 4 hours after I did on Saturday (the same place) for a non functional slide issue, and he got a call Tuesday morning (yesterday) that his TT was repaired and ready for pick-up!!

This RV service center doesn't sell RV's, they only service them. The owner of the facility a number of years ago use to be the service manager at the Jayco dealership that I've purchased my last two Jayco's from.

Not a big place, but clean, do good work, and have an impressive parts inventory. I drive through the area often and they seem to always have a pretty steady business.

All three of my BIL's take their RV's there for service.

CTPR, Inc.: CAMPER / TRAILER PARTS & REPAIR INC. | fowlerville, MI 48836

Bob

[Rustic Eagle]

RV tech called today, TT ready for pick-up.

Bob

[TobyMcCann]

Bob,

Greetings. Have you had time in your TT since having the new toilet and 360 Siphon installed? Has the Siphon made a noticeable difference?

[Jayco1101]

Are you leaving the exhaust fan on over the toilet, often times this will pull gases up from the tank. You may need to also give the black tank a good "degreasing". Even though we believe we adequately flush them black material can still be built up on the walls and base of the tank. There are several great videos on YouTube and such on how to fix these issues...good luck!!!