Kohler toilet slow leak - what is causing it?

[kolcun]

I've got an older kohler toilet. I hear a short period (few seconds) where the water is running to refill the tank. I can't figure out what is causing the leak.

I replaced the flapper recently, and there is no water leaking onto the floor.

Based on a dye test, it's about a one tank per day leak.

What/how should I check to isolate what's leaking? The leak is slow enough that I can't see water running into the bowl or anything like that.

Otherwise, it flushes fine, and works well.

Thanks!

[shock]

There may be some crud built up where the flapper valve makes contact preventing a good seal! Did you try cleaning that area?

[kolcun]

I'll give that a shot, but it looked OK when I replaced the flapper.

If that doesn't work, is it possible that the plastic part that the flapper meets should be replaced?

any other parts that may be the cause?

Thanks.

[sloooo]

I always replace the flapper and seat together. If one is old and the other is new, you could have some mating issues, so to avoid that, just replace the guts all at once.