Hmmm, we have Wellworth toilets. The round bowl models perform very well, and are quite quiet, but the elongated bowls leave streaks in the bowl. Anyway..

That's hard to believe if you swapped out the flush valve twice. (Just to be clear, the flush valve is the one in the center with the overflow tube, flapper, etc.) It still sounds like the flapper and/or seat. I'd swap the flapper one more time if you have one around, or maybe buy the fluidmaster replacement flapper/seat combo and glue it in there. (If you go that route it's about a $12 kit. Follow the directions exactly, since the placement of the hinge is a bit counter-intuitive.) That all being said, I still fail to comprehend why replacing the flush valve combo (twice) didn't take care of it.

BTW, is the skinny fill tube clipped onto the top of the overflow tube (aimed into the tube). It should NOT be just stuck down in there.

I just wanted to add that it is the ceramic drain hole that I wonder about. The tank had a styrofoam liner that I had to remove on the inside bottom of the tank to get at the gasket screws. Could that have something to do with the flush assembly leak? And my water has lots of iron in it.

Thanks homebound. I will try the third flapper I received amongst all these flush valve kits. I really thought the $30 Kohler flush valve assembly would solve the problem... As last resort I'll do the glue-in fix.

The fill hose is clipped above the fill tube.

I've learned a lot about toilets, so maybe this is fate leading me to the next lesson of toilet replacement.

BTW, your OP didn't indicate this, but let's confirm the water isn't running over the top edge of the overflow tube. (If so, that would be related to the fill valve and/or it's height relative to the overflow tube.

But your problem happens ever when the water is turned off, so I don't think this pertains to you. Just to be sure, though.

Good luck.

Are you sure the flapper is against the ceramic of the tank?

Most of the time the flapper seat is part of the overflow assembly.
Without a surface finish the inside of a tank IS to rough to use as a valve seat.

I _think_ it is. Last night when I tried installing each entire flush valve assembly again (I am getting good at taking the tank off!), I accidently got the Kohler nut not quite tight enough and water gushed out the back when I flushed. So I spent quite a bit if time making sure the whole assembly was seated correctly on the ceramic tank drain hole before I attached the tank to the bowl again.

I guess I could take it all off again, make sure the drain seat is smooth and then check the flapper seal again to make sure there isn't debris in the flapper connection.

Along those lines, I wonder if you tightened the flush valve assembly to the tank tight enough. Use channellock tongue-and-groove type piers to make it "quite snug" - but don't wrench the heck out of it)

Here is a link that might be useful: Pliers

A 10" pair of tongue and groove pliers is a tool no DIY homeowner should be without. They will reward you over and over again. Buy a good pair - no dollar store junk.

That was my first thought. I used a vise grip to tighten it 1/2-1 more turn than I could hand tighten. I need a pair of those PVC channel-lock pliers that maybe wouldn't bite into the plastic nut and make burrs.

Last night I left off the plastic O-ring washer that came with the Kohler flush assembly nut and it seemed to leak less in my informal "hold the tank over the bathtub and see where the leak" is test. But at 1:00am, I was afraid I would drop the tank and quickly fit it back on the bowl before I broke it.

OK here is my summary of next steps:
- clean the flapper again, make sure it sits in the seat
- try to re-tighten the nut holding the assembly to the tank
- if necessary use the glue-in seal repair kit for the drain/flush assembly connection
- if necessary buy a new toilet--ARGH!!!!!!!!!!!!

Did I miss any other trouble-shooting tests?

Is there anyway the styrofoam insulation had a role in sealing the drain? I can't remember how close it was to the flapper.

Should I put the O-ring washer back in?

Looking at our Wellworth, turn the asssembly so the overflow tube is oriented toward the left/back of the tank, i.e. overflow tube is closest to that corner. Next, slip the thin gasket on the threads underneath, followed by the plastic nut. Hand tighten (keeping everything fairly level), then tighten securely with wrench.

After that, put the foam gasket over the nut and install the tank to the bowl. (Note that the tank to bowl bolts need to be securely tightened to the tank first, then attach the tank to the bowl with a second set of nuts & washers. And don't tighten one bolt all at once - you should go back and forth tightening one bolt, then another, watching to keep everything level, etc.

I called Kohler 1800-456-4537 and they were very helpful in troubleshooting. They are sending me a new tank seal #53154 --that is the part that fits on the flush valve above the threads and makes a watertight seal with the tank from inside. We'll see in a week or so if this $1.60 part will stop the leaking!

I really like the interactive parts diagram they use online (link below). you can enlarge it and click on part number for more detail.

Here is a link that might be useful: Kohler Wellworth toilet model 4512 parts diagram

Looks about like 90+% of the toilet flush mechanisms out there.

The flapper seals to the top of the large ring beside the overflow pipe.

If you have ANY chemical treatment in the tank, get rid of it.

The bleach tabs are VERY hard on the plastic and flexible parts of the mechanism.

They even attack silicone flapper valves and slowly cause them to stiffen (and then not seal well).

Some toilets seem to operate for many many years with few issues, while others (even on the same water system) get rough spots on the flapper seats.

They can sometimes be scrubbed smooth with non-woven abrasive (even the stuff on a sponge) and made to work again.

I've changed out:
-tank-to-bowl seal (original problem was an external leak, and it could be I never noticed also the fill valve always slightly running)
-flush valve assembly (tried Fluidmaster and Kohler)
-fill valve assembly
-tightened nut on flush valve (but it is not leaking outside)

But with the water supply off, the tank is still draining pretty quickly, it's halfway down in 30 minutes, and the food coloring is showing up in the bowl within 5-10 min. The fill valve is always running slightly unless I turn the water supply off(kind of a hissing sound).

I can't think of any other repairs. Is now when I bite the bullet and learn how to install a new toilet?

"I can't think of any other repairs. Is now when I bite the bullet and learn how to install a new toilet? "

You may well have the same problems with a new toilet, they have most of the same seals and valves and require assembly.

If you cannot install new parts in an old toilet and make them seal, you will have the same problem with new parts in a new toilet.

Thanks for your reply brickeye.

It would be very interesting to hear your outcome. Your posts sound like I had written it myself. The Kohler toilet started to leak as did yours. The flapper valve was dried out and warped. I replaced the flush valve twice then went on to replace the various components of the of the flush tube assembly once and ultimately the entire flush valve as a kit twice - the first was from Kohler and the second an after-market one. Interestingly, no matter what part I change ... or even the entire assembly, the rate of water loss from the tank does not change from one repair attempt to the next. A local hardware employee (whom I know personally as well outside of the workplace) suggested using a silicone sealer between each of the pieces to try to get a better seal ... again no change in the rate of water escaping down into the bowl. I have had the toilet tank apart approximately 12 times in the last 2 weeks. Likewise I have checked carefully for chips and cracks in the tank only to find none. The leak does not make sense. I would atleast expect the rate of water loss from the tank would vary a little from one repair to the next ... tomorrow I am going to buy a non-Kohler toilet; from on-line searches I understand Kohler has had a significant problem with some of their products ...

I suspect he has a very common error when installing a flush valve.

When installing a flush valve the rubber flush valve to tank gasket should be installed on the flush valve before it is inserted through the hole in the tank. That will seal the flush valve to the tank.

If the flush valve is inserted first and the rubber gasket installed on the underside of the tank water can seep under the flush valve flange, down through the threads on the flush valve and into the bowl in the manner he has described.

Also, whenever I install a flush valve I put a light film of silicone sealant on both the top & bottom surface of the gasket.

I prefer to use a sealant called
Plumbers Goop" which comes in a small 3.75oz tube and can be found in any hardware or home supply store.

I made an illustration to show how the gasket should be installed and I found an illustration of the Plumbers Goop in the standard retail packaging.
. .

I have that exact same toilet with the exact same problem. It drains about half way down the tank and then it stops leaking. So I know its not the flapper. I put in a new flush valve, I even put in one of those new flapperless attachments. It still leaks. The only thing I can think of is that when I cut the overflow tube, I might of put a crack in it. I'm going to try a new flush valve. If that doesn't work, I'm buying a new tank.

How did you resolve your issue?

Fred

I know what's going on since I had the same problem. What's happening is the water is being siphoned from the toilet bowl through the rubber fill hose at the top of the supply valve. You need to make sure that the end of this rubber hose is above the water line in the bowl. Take a flash light and look into the overflow pipe where the rubber hose in inserted. You will see water is being siphoned after the supply valve stops as long as the end of the rubber hose is below the water line in the bowl. All you need to do is to raise it above the water line and secure in that position. I hope this help. It took me 2 weekends trying different things and as soon as I looked into the overflow pipe and saw water coming out of the rubber hose, I realized that water is being siphoned from the bowl. The water supply valve I have is one of those Fluidmaster valves with the float riding on a vertical tube.

Thanks to "ggin2000" posting about the rubber fill hose siphoning, I have my own tank leak issue resolved, FIANLLY! Thanks so MUCH!

How did you end up resolving? I replaced flash valves on 3 sterling toilets. They are of similar design to Kohler. 1 is fine but 2 have slow leaks into the bowl. Seems the flappers will not seal. I have now tried 2 different kits and different flappers.

Thank you ggin2000. I had already changed half the parts and would have kept going if I hadn't followed your advice. Snip of the scissors and problem solved!

I was sure it was a seal somewhere but turned out your's was the best solution for my issue. Certainly explains the consistent leak others are describing despite changing parts.

I experienced same issue, 2 flappers and 1 complete flush valve kit later and still leaking, removed flapper and seen water is leaking under the flush valve seal inside tank. Solution: remove flush valve and sand surface of tank where seal sits, next add waterproof silicone to one side of new flush tank seal surface where it meets tank, install let dry overnight and you will be happy as a lark with leak solved

ggin2000 - thank you! I had made sure there was no leak before putting everything back together - no leak! Great! Then when I tightened everything down and put it all back together, the leak started again. WTH!?!? As soon as I read your 7 year old post, I realized that that was my problem... boom - no more leak.

I worked on a Kohler Rialto K3402 built in 1988. The toilet kept loosing water from the tank and the fill valve kept turning on every 10 to 15 minutes. Thinking it was a flush valve gasket leak, I changed the gasket, not once, but twice, only to experience the same problem. The Kohler fill valve had been replaced prior with a replacement Fluidmaster fill valve. I finally realized the problem after noticing water trickling from the rim of the bowl into the bowl itself, which would eliminate the leak coming from the flush valve assembly. It was actually water getting past the rim tube (the 1" white tube inside the tank that passes through the forward tank wall into the bowls rim). Solution: I shut off the water supply and drained the tank. Took clear silicone and spread it around the rim tube with my finger as best I could. I set the water level as low as I could, so the only exposure the rim tube had with the tank water was approximately 1/3 of the tube. Apparently, the silicone around the bottom part of the rim tube was enough to stop water from trickling into the rim of the bowl. Bottom line: If you see water trickling into the bowl after the tank fills, most likely this is the source of your problem.