Toilet sewer gas

I just replaced the wax ring of a toilet leaking sewer gas, it still stinks in the room. House is 80 original drains. What is the most likely cause of the smell.
Can a clogged vent stack cause this smell. If so, why , it is only open at the exit on the roof- right. Windows are sealed closed. Or is it more likely a cracked drain pipe or bad seal of connected drain pipes.
What is the best way of finding the leak without ripping out floors and walls.
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m Ransley wrote:

I have on occassion used a combustible gas leak detector (TIF) to find sewer gas leaks. Pretty good at pinpointing the source but depends on the wind blowing right. But if the leak is inside a wall it won't X-ray it for you...
Jim
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I just had a problem like this in an upstairs guest bathroom that we rarely use. Turned out that the sinks, shower and toilet all have traps filled with water that prevent sewer gas from excaping into the bathroom through the drains. They hadn't been used for so long that the water in the traps had dried up. All I had to do was flush the toilet a few times, and run water in the sinks and shower for awhile. That solved it. It also cost me the price of a plumber's house call to find this out. I hope your problem is this simple.

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Another thing to consider: mold/mildew in the holes around the top of the bowl...and in the over-flow / vent hole in your sink.
I've been chasing a similar problem in an under-used bedroom bathroom for a few months now. After what seemed like countless hours playing "Columbo", I traced the origin of the smell to this mildew build-up. The problem is - cleaning it isn't easy. I've been flushing both areas with bleach off and on. The smell goes away (as does the "visible" mildew)...but comes back eventually, as the mildew grows back. It's hard to deeply-clean these areas, because there is no easy access to them.
I realize that I could just solve the problem by replacing the sink and the toilet, but that seems like a waste; There's nothing mechanically wrong with these units.
Just my two cents.
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snipped-for-privacy@webtv.net (m Ransley) had written

Yes! Get up on the roof with a flash light. Remove the cap and see if you see an obstruction. A drainsnake can help you out. Mine was a bat that died trying to get back out.
--
Barney __________________________
"Name calling is best left to the children."
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