Motorhome smells like rotten eggs

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Squirrel

Squirrel

Active member
Joined
Jul 9, 2010
Posts
36
Location
BC, Canada
I posted this on another smaller RV message board, but then I discovered this place today and thought I'd post it here in case anyone has any thoughts.

We took our new (to us) motorhome out for our first overnight camp at a nearby RV park. There is a stink in that thing that we can't figure out how to get rid of. We assume it is something to do with the toilet or the black water tank? We've filled the black water tank three times and dumped it at a sani-dump. We've bought some orange liquid from the local RV dealer that is supposed to control odor for "up to seven days" but it hasn't made a shred of difference since we added it yesterday.

It doesn't actually even seem to be coming from the toilet itself. We open the bathroom door and no new smell wafts out. We open the toilet lid and same thing - no new burst of stink.

It was horrible last night, smelling similar to rotten eggs but not quite. Not sulfur, but something like it. Like lots of flatulence hovering around.

It got better by morning when we had run the roof air for an hour or so. I walked into the motorhome at one point and noticed, "Hey, it doesn't smell."

We haven't even used the toilet once. We don't want to make it worse.

We used the RV park's sani dump. Then we followed the instructions on the orange liquid's bottle and put in a few ounces followed by some water. Then we drove home (20 minute drive).

Within a few minutes of driving it started to stink again. It seemed to get worse the further we drove. I thought the dash air was making it smell worse so I shut that off. Didn't make any difference.

The smell was there when we first looked at the motorhome before buying it, though not near as strong.

Any ideas what might be wrong and what to do?

Someone at the other board suggested if we had a gas engine it might be the catalytic converter.  Our motorhome engine has a propane conversion and we've only ever used propane to run it since we got it a few weeks ago, as did the guy who owned it before us.

Another commented included this:

"Your problem is probably the battery or batteries being boiled, cooked, baked and burned by the alternator when you're driving and by the converter when you're hooked up to a power post. No telling how long they have been dry and overheated. When they get bad enough to make that smell, they need replaced. "
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And doing some internet searching, I found that it could possibly be our hot water heater.

Any thoughts?



 
I would have to agree with the batteries being BAD!  Had the same thing happen in our semi a few years back.  If you're smelling them, it's definitely time to replace them.

Happy and safe travels and enjoy your new MH  :)
 
All the items mentioned are good places to look.  Chasing smells can be like tracking down leaks.  You almost have to go after all possibilities if you are going to get piece of mind that you got it.  So here are a couple of more places to look.  You didn't mention gray tank but food bacteria can make bad smells there.  Also the vent pipe going to the roof may have separated.  Usually happens right below the exterior roof.  It may also be the toilet seal to the tank.  Good luck.
 
Another possibility is the air admittance valve (often called a vacuum breaker) which is often on a stub off the drain pipe on bathroom and kitchen sinks. It has a flap that is supposed to open when you dump to keep the water in the traps from being sucked out. If the flap doesn't close back you will get an odor.
It is screwed on and you can get replacements at Lowes and Home Depot.
 
Chances are it is the flapper mentioned by Clay.  Replacements cost around $3.  Buy two of them and see if that doesn't solve the problem.  Also be sure that you have water in the traps (sinks & shower).
 
There are several possibilities, but the most likely is either a bacterial growth in the hot water tank or or fumes from the gray water tank, entering the rig through the vacuum breakers that Clay mentioned or a sink drain trap that is empty. Other possibilities are a badly failed battery or a failed refrigerator cooling unit, but you would probably have noticed other effects of either of those.

I gather this is a recent purchase, so chances are it was sitting around a while before you bought it. That makes dry drain P-traps a good possibility. Does the RV have a washing machine? If so, run it though a cycle to make sure there is water in the washer drain trap. Ditto for each sink and shower.  And also fill and flush your gray tank if you can. Gray tank odors are far nastier than black and have the characteristic smell of rotten foods.

I would also drain the fresh water system, including the water heater tank, and sanitize it. There is  a bacteria that thrives in hot water that has exactly the smell you describe and you get that odor every time you run the hot water and often with the cold as well.  There are instructions in the Forum Library:
http://www.rvforum.net/joomla/index.php?option=com_content&view=article&id=110:water-system-sanitizing&catid=42:fresh-water-systems&Itemid=45
 
You mention it was converted to propane. Is the propane tank full, if so the pressure might be causing it to bleed propane. If it is near empty they some times also smell. have a propane dealer check for leaks.
 
Wow, lots of answers for us to think about!  Thank you all.

We are very new to the world of RVs indeed.  We only bought this thing a couple weeks ago.

This might sound like a stupid question but I'll probably have a lot of those:  What is a "trap" that several of you have mentioned?  More specifically, how do we go about finding these traps in our RV?
 
John Hilley said:
You mention it was converted to propane. Is the propane tank full, if so the pressure might be causing it to bleed propane. If it is near empty they some times also smell. have a propane dealer check for leaks.
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I don't think it's propane.  I know the smell you mention as I used to live in a remote part of Alaska where my stove was run on propane tanks.  I could always detect when a stove burner was on with no flame, or when the tank was low, and it's not those smells.
 
1GypsyRose said:
I would have to agree with the batteries being BAD!  Had the same thing happen in our semi a few years back.  If you're smelling them, it's definitely time to replace them.

Happy and safe travels and enjoy your new MH  :)
Click to expand...

The guy from whom we bought the motorhome tells us the batteries are brand new.  Not sure how to verify that.
 
Look on the batteries, there should be the month and year sold indicated somewhere and stamped in the top of the terminals or ??? should be the month of manufacture.
 
Most batteries I have used over the years have a label attached where you remove a little dot at time of purchase...Month and Year.

This only works if the buyer took the time to do that.  If unknown, a battery test is probably your best bet. (AutoZone, Advanced Auto, Napa  or your favorite auto tech, etc.)

Carson FL
 
Well, here's an update.

My husband just went outside to check for the dates on the batteries.  Pretty quickly he excitedly called me to come outside.  "I think I found the source of the smell.  Come smell over here and let me know if that's the same smell."

It definitely smelled the same as what we've been smelling.  It was as we stood outside by the battery compartment.  I had to get in quite close to smell it, though.

We still can't see the dates on the batteries.  They are sitting on a piece of wood that looks like it should slide out but we can't pull it out, probably due to the weight of the batteries?  I'm afraid of batteries so try to avoid them.  Maybe my husband will get them out somehow.

I went inside the coach and can't smell the odour anymore.  It's been sitting for about 24 hours now in mostly cloudy and rainy conditions.  Seems to get worse when it's sitting under blazing hot sun.  But what's up with it smelling so bad all night long as we slept at the RV park?  Same thing when my husband and some of the kids slept in it here in our yard last week.

I'm hoping it will be a problem that can be solved without too much expense.  Thank you to all the wonderful detective work of folks in this forum!
 
Another update:

My husband just said the one of the batteries is really, really, really low on water.  He's out there putting more in right now.
 
Tell him to tighten the battery terminals while he is there.
 
My husband put water into the batteries.  We could not find a date.  There were some numbers and month names in little circles but none were punched out.  The batteries do look new, though.

Now he's got the batteries sitting back where they belong, with water in them.  He removed a fuse because he wants to have them be disconnected until we need them.  IE, we can just use stuff that requires electricity when we are plugged in at home or at an RV site.

He's asking, "When the motorhome is running, do those batteries charge?  If that's the case, I have to put the fuse back in."
 
Squirrel said:
Now he's got the batteries sitting back where they belong, with water in them.  He removed a fuse because he wants to have them be disconnected until we need them.  IE, we can just use stuff that requires electricity when we are plugged in at home or at an RV site.
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If you have not charged the batteries to a fully charged state, you should do so ASAP. It is not good to have batteries sit for extended periods in a discharged state. They will become sulfated and loose the ability to hold a charge.

Richard
 
Squirrel, do you have a friendly neighbour that knows a bit about RV's?  A few minutes of instructions would do wonders.

Carson FL, (ex-Vancouverite) (notice my spelling of neighbor?  :)


Carson FL


 
The house batteries do indeed charge while the RV engine is running. But they also get charged when the RV is plugged to shore power. He should put the fuse back in and let that happen for at least 24 hours.

A battery that is releasing lots of hydrogen can smell like rotten eggs. It will also probably get hot while it is charging, so a hand on the battery might tell you something. Watch the battery that was low closely - if it is warm/hot and emitting a LOT of bubbles, it may be your smell. Probably need to replace it.

Carson gave good advice - you need a couple hours of hands-on advice from an experienced RVer.
 
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