Puzzling Toilet Problem

[Tony Sivori]

Odd toilet leak problem here for anyone who wants to take a shot at a hard to diagnose condition.

Symptom: Toilet tank leaks into bowl, causing very frequent (every 15 minutes or so) top ups of the tank. The leak is really bad; in reflective light, water in bowl ripples noticeably after tank finishes filling.

The tank is not overfilling, water is not entering the bowl via the overflow tube.

Obvious likely cause is the flapper. Replaced. Problem persists, unchanged.

Next. Using gently duty scrunge, clean seal that flapper seats into. Problem persists, unchanged.

Next. Try light coat of plumbers grease on flapper and seal. Problem persists, unchanged. Try heavy coat of plumbers grease on flapper and seal. Problem persists, unchanged.

Carefully inspect fill tube to be sure it is not cracked and leaking from tank into bowl. No cracks or seepage found.

The last possible cause (leaving out cracked porcelain) is the rubber seal between the tank and the bowl.

I worked a lot of overtime this week, and I haven't had time to make another parts run and remove the tank.

As luck would have it, the manual shut off valve leaks when closed. This means that when the water supply is shut off, the tank slowly (about one hour) fills itself to the full normal level.

Here is where it gets weired. When the tank fills slowly through the leaking water supply manual shut off, the tank does not leak into the bowl. No leak at all.

WTF!? Wouldn't a leaky seal leak whether the tank fills very slowly or at a normal pace? Why would that make a difference?

[Frank]

I'd suspect seal between tank and bowl. I've had to replace one for same problem.

I've also seen bolts between tank and bowl corrode to the point of failure causing leak.

[Joerg]

That points to the fill valve. What kind is it? I sometimes had that happen that on 40 year old Kohlers. Slow leaks, drip .. drip .. drippity-drip .. drip ... No leaking when shut-off almost closed but leaks when fully open. It was the little hose that goes into the overflow pipe.

[jamesgangnc]

He said: The tank is not overfilling, water is not entering the bowl via the overflow tube.

I have had that happen because of the seal around the flapper seat to the bottom of the tank. Since it's over the hole going into the bowl the water ends up there.

[Home Guy]

If you touched the rubber surface of the flapper and something like black ink comes off onto your fingers, then I'd say it's time to replace the flapper. Otherwise, the flapper is not likely the cause of the problem.

As has been mentioned, the problem is either

a) the seal between the tank and toilet bowl, or

b) the seal around the bolts holding the tank to the bowl

If the tank was bumped or roughed up, that would account for a loss of seal at either (a) or (b). Possibly the tank was knocked around so bad that a crack formed around one of the bolts.

I always fill up the holes where bolts go through the tank with silicone when doing a toilet repair job. You should have bolts with very wide, flat heads, along with a tight-fitting rubber washer to help it seal. I put silicone around those parts as well.

Tightening the bolts too tightly can distort the gasket between the tank and bowl and cause it to leak.

You'll have to take the tank off, and by the looks of it you'll also have to shut off your main water valve and replace the shutoff valve near the toiled because it doesn't work properly.

[Tony Hwang]

Hi, I'd feel around flapper seat. Maybe something. small particle(s)lodged or uneven edge due to deposits. Quite common issue.

[Marilyn & Bob]

Sounds like there is a problem with the flapper seat. (Although it doesn't expain why you don't have a leak when the water is only trickling into the tank). There are a number of flapper kits that come with seat repair as well. Worth a try. Here's one:

[Tony Sivori]

Already replaced both cut offs on the wash stand. Tried to replace the toilet cut off, but it didn't want to crack loose and I was afraid of breaking off the 55 year old pipe.

[Tony Sivori]

The back of the toilet tank is tight against a tiled wall, so there is the possibility that there is a bind between the tank and bowl.

But I think that the bolts would leak onto the floor, not into the bowl.

Also, I'm told, it is easy to crack the porcelain.

[Tony Sivori]

A Flushmaster, installed about one year ago.

I think if the fill valve were leaking, the water would overfill the tank.

[Tony Sivori]

That's probably it.

The only thing I can think of regarding the lack of a leak when the tank fills slowly is that maybe the velocity of the water is getting past the bad seal, but the seal is good enough to contain less turbulent water.

[greenpjs]

No. There is an overflow that causes the excess water to go into the bowl before it would overflow the tank. That could be what is happening in your case. Make it happen on purpose (by holding the float up) while you are watching and you will see what I mean.

[Vic Smith]

That's probably the cause. If the valve doesn't close fully water will overflow into the overflow pipe and into the bowl. You can see that easy enough. But the main water outlet is at the bottom of the tank. The tube going into the overflow pipe isn't under any head pressure so a minor leak in the valve the water will flow there first. That's assuming there's only one actual valve for both main outlet and tube, which is probable. Never took one apart so that's a guess. An easy way to prove it is to pull the tube from the overflow pipe and see if there's water coming from it when the valve is supposed to be closed. I think Tony said it doesn't always do it, so there might be some grit in the valve. Tapping the valve with a screwdriver handle while open may clear it out.

--Vic

[jeff_wisnia]

Uh, don't you mean holding the float DOWN?

Jeff