American Standard Champion toilet keeps running

Start with the flapper. They tend to dry up especially with water that contains chlorine. Purchase the American Standard flapper if available for that toilet. Works better than generics.

you are wasting your time complaining on fixya site
the correct action is to take the lot back and get a refund for a product -not fit for the purpose ---

I would ckeck to see where water fill line is inside toilet tank and then adjust flush valve to try to get it to shut off at this point. Not knowing whether your toilet still has original flush valve it is hard to tell you how to fix it. If it has float mounted on rod to flush valve there is usually a set screw on the top of the flush valve in the center. Turn this screw clockwise to make valve shut off sooner. Try to set it so that water shuts off when it is at fill mark. If float is mounted on brass float rod you can support rod closest to flush valve with left hand and carefully bend rod down a little with your right. This will cause flush valve to shut off sooner. If the seat is worn to badly in flush valve you will need to replace it.

probably the flapper valve is not seating correctly over the outlet. you can fix it by reaching in and twisting the valve one way or the other till it seats properly and the leak will stop.

Replace the flappers, and clean around the flapper seat.

Make sure the water level is 1/2 " below the large vertical tube by either bending the float rod down or adjust the skinny silver rod on a Fluidmaster unit.

the float is set too high

your float is stuck

you need to replace the flapper, it's allowing water to seep thru

The foam block does a few things: It helps with noise level, helps prevent condensation and also takes up space in the tank to lessen water usage with each flush.
Keep an eye on the outside of the tank and if you don't ever notice any moisture on the outside of the tank then I wouldn't worry about it all!!

I have the American Standard Champion 4 toilet. Water is leaking from the tank to the bowl causing the toilet to refill. I've replaced the flapper and cleaned the surface the flapper contact. Nothing seems to work.