My upstairs toilet doesn't get used that often, but when it flushes the bowl refills, then the following morning it is completely empty. I can smell a sort of gas. I am in the middle of nowhere .on my own and a plumber will charge an arm and a leg to come out. Will I be able to fix it myself? I have no near neighbours.
Thanks for any help.

Check to make sure the little tubing that runs from the ballcock is connected to the white overflow tube. This is what fills the bowl, see the images below, thatnks.

John

You may have a faulty atmospheric vent. Sometime small animals get clogged in the vent tube allowing all the sewer gases to linger in the pipe. I suggest you buy a hose bladder available at most hardware stores and enough hose to reach down into the vent pipe past the upstairs toilet. Follow the directions included with the bladder.

A hose may not be the right thing to do, but running a plumber's snake from the roof vent is.

You do have to be careful not to loose the snake. You can go manual, drill operated or integral power snake. The last one can be rented.

The other experts are focusing on the vent. I have a different take on it.
There could also be a factory defect in the bowl. Sometimes in casting the bowl there is a small bubble in the china. Instead of junking the bowl the manufacture will put a porcelain patch over the hole and send it on through. On occasion the patch will fail allowing the water to seep out of the bowl. If that's the case you would have a full bowl after you flushed and the bowl filled but some time later you would notice a drop in the bowl level. The only other thing might be if you dropped something in the bowl and cracked it. If you're worried about where the water's going, in both cases it drains back down into the sewer and not under the bowl on the floor. To check the bowl must be pulled, filled and put up on saw horses. You can then see if there's any leakage from the bowl.
However, Sometimes a blocked vent can "vacuum" water out of a bowl. Does the level "bounce" up and down? Good luck, Tom

Iceni,

Please follow TOM's instruction but it would not hurt check the small hose connected to the overflow tube,lift the tank lid and see, Thanks.

John

Not a question. But thanks to all who posted. I like the diagram.I am a woman and that helps. The toilet is very old, but no cracks as far as I can see.

If the bowl was filed up when the ballcock shut off then the white tube's connected to the overflow tube and is doing its job.
While a clogged vent can lower s bowl level it takes a lot of vacuum to empty a bowl, especially during the night when no fi\xtures are being useed.

The toilet is very old, but no cracks as far as I can see.
If there were one you wouldn't see it. It would be lower in the bowl.
From what you have told us my bets on a cracked bowl. However the only way to tell is toPull the bowl and check it. To check the bowl you must first pull it and put up on saw horses. Then fill the bowl and let it set. You can then see if there's any leakage from the bowl. Good luck, Tom

Sorry Tom I miss read the post was thinking of low water level in the bowl,Thanks.

John