OK, old toilet located on the 2nd floor, probably 30+yrs old, so its a big tank and it drains slow. Too much toilet paper (we won't get into that, I'm still fuming). I flush, of course its clogged, but does not overflow the bowl, it makes it to the top of the bowl, but does not overflow. The bathroom floor is dry (thank god). Fills up to the top and then slowly drains down. Now here is the part I cannot figure out. The ceiling below the toilet (or in the general area) is leaking on the first floor. How can this happen? The bathroom floor is competely dry. Any ideas? thanks!!
First of all if the toilet is upstairs, the line is not plugged, just the toilet because everything downstairs would be flooded out first.
It may be the jets - under the rim are plugged in which case you can use a mirror & flathead screw driver to unplug them.
It could also be that your water level is low - in the tank the water should be about 1/4 inch from the top of the overlfow tube in the middle.
Then too, it could be that the throat of the toilet either has something in it (pen, q-tip etc) or that the toilet is just old & the calcium build up is starting to really effect it. It might not be such a bad idea to change it if you own the home.
Second is that water will seek its own level - most likely there is a breach in the wax seal & when flushed the water will run down the pipe & follow it till it drops (that's about the best I can explain it because water does not always drip straight down).
My educated guess, without being able to test it is that changing out the toilet would solve all the problems.
Here is an important rule of thumb - if you pull the toilet & replace it use a wax ring without a flange if the pipe is jagged (you could even use 2 if necessary) - use a wax ring with a flange if the pipe is smooth.