Toilet flushing problem

I'm hoping someone on here can help me. 2 weeks ago my toilet in the upstairs bathroom clogged. I am on town water/sewer. I bought a 3ft auger and got it mostly unclogged, I got water to go down but slowly. I kept filling the bowl with hot water but it would only go down with help of a plunger.

Someone at work brought over a 6ft auger and could not find a clog or obstruction. It flushed fine. The next morning it worked fine the first time but the 2nd, it took a very long time for the water to go down. This toilet is directly above the first level one which works fine so I know the main pipe is ok. My coworker came back and took the toilet off and could not find anything in there. He ran the snake down the drain hole in the floor and did not find an obstruction there either. However, when he flushed the toilet to empty the tank, the water would not go down without plunging it.

I don't understand why if it is not clogged, the water won't go down on its own. I have owned the house for 11 years but I do not know if the toilet is original, the house was built in 1986. I live alone so there is not as much use as a large household with kids. I have another coworker who is going to look at it on the weekend but not sure where to go from here. We have apartment buildings so these guys are used to working on toilets and unclogging them but have never come across this problem. One person has said just to install a new toilet but i'd hate to do that and find it doesn't solve the problem. Are there any pros out there with some suggestions?

Try flushing the toilet with a bucket of water. Fill the bucket with at least 3 gallons of water and pour it very fast into the bowl. If it flushes there is no stoppage in the toilet.
What happens with older toilets is the passages from the tank to the bowl become restricted with deposits, not allowing the water into the bowl fast enough to flush the toilet.

John

Thanks for the quick reply John. Once the toilet was removed, it was found that the ring/collar that fits in the floor needs to be replaced so it has not been hooked up again yet. I remember having to do that at a previous employer when we had no power for 2 weeks. If it works with the water, does the toilet need to be replaced or is there some kind of cleaner/chemical that will dissolve the deposits?

Sometimes you can open the ports underneath the rim with a nail held in a pair of pliers.

If the toilet is no longer attached to the floor, do the same test that John recommended, but directly into the drain at the floor. A large bucket of water into the flange quickly, but carefully, should let you know if there is a clog farther down in the drain before the first floor. Maybe even several buckets to confirm it.

We did try that Saturday and the water seemed to go down fine, as far as we could see. There was a curve or elbow but maybe it would be a good idea to try a few more buckets at once and see what happens. Thanks for all the suggestions.