I have been hearing whistle noise from one of my toilets. It sometimes lasts for minutes. It happens without any toilet activities or after a flush. Can you tell me what the problem is and how to go about fixing it?

Try to open and close your angle stop ( water supply valve) few times.

Next time you hear the noise again, open up your toilet tank and try to locate the source. It may be that your fill valve doesn't hold pressure well and is releasing small amounts of water into your tank (trying to refill ). Pick up the float with your fingers and gently move it up. See if the whistle stops. If that's the case, than look if your water level is too high and slowly overflows over overflow tube into the bowl. If that's the case, you will need to either rebuild the fill valve or buy new one.

Also, there is a chance that your flopper is not sealing and is releasing small amounts of water into bowl. Fill valve then tries to refill. If this is the case, than you would have to replace flopper. In this case, water level would be bellow the rim of the overflow tube

I don't see any cause for the toilet bowl to make such a sound.
Therefore the problem has to be related to the water tank.
May be the floater is "leaking" a little water.
Open up the water tank and check if the water level is higher than normal.
That problem almost always is caused by dirt blocking the automatic valve system (fully or slightly).
Although moving the floater may stop the "leak", the permanent solution is :

1-Close the in-line supply water valve.
2-Remove the floater.
3-Open the automatic valve.
4-Clean the system from small dirt and/or calcium deposits.
5-Re-install everything in reversed order.

Success !

:)

I have been hearing whistle noise from one of my toilets. Hello bibler:

You must have an awfully good looking tush.

excon

Hi bibler,
A couple of things.
1. The toilet is probably running because the rubber stopper known as the flapper is worn out and needs to be replaced, Simple job.
Also sometimes the seat where the flapper seals the tank gets worn and may also need to be replaced. Little more difficult but not bad.
2. The whistling is the water going through the ball cock. Sounds like its old too and could be replaced. Replace it and the sound will go away is my guess, again not a hard job but messy if you are not careful, have a few towels with you.

Best of Luck,
John