How to Fix a Kohler Toilet That Keeps Running: Common Issues & Troubleshooter

Kohler, the most popular toilet manufacturer in the USA, uses many patented technologies that make its products stand apart. That’s why knowing how to fix a Kohler toilet that keeps running is a bit different from adjusting other toilets.

They have unique valves, exquisite components, and from the beginning, these toilet mechanisms have special tools that enable customers to fix the most common problems without calling a plumber. Here are instructions and tips if you want to fix your toilet by yourself.

Brief Guide on Fixing Kohler Toilets

As a major manufacturer with over 24% of the American market, Kohler uses patented solutions for its toilet flushes, which makes fixing and replacing them easier.

So, how to fix a Kohler toilet that keeps running is less of a problem. You will need replacements from the official store and some expert guidance.

Why does your Kohler toilet keep running?

There are many reasons why the Kohler toilet won’t stop running, but mostly it’s about damaged or worn out valves, flappers, or seals. So, when you ask “why does my Kohler toilet keep running?”, the truth is out there.

You’ll have to learn a bit and spend a small sum on replacements, but knowing how to fix a running Kohler toilet is faster and cheaper than calling a plumber.

How to identify the exact problem

The worst way to recognize a problem is to see your bills growing. You might also hear the sound of water flowing in the toilet. Then you need to identify the vulnerability, which mostly means determining the place where it happens.

How to identify its location

To locate the place of the Kohler toilet tank leaking, take food coloring and drop some drops into the tank. Wait 10-15 minutes until a leak exposes the place.

If there is none on the tank, it must be the flush tube: then it’s the bowl where the water gets colored. Wash the toilet and replace the water by flushing right after that.

Step-by-step guide on how to replace the flapper

If your Kohler toilet fill valve won’t shut off, the problem part might be the flapper valve, a small rubber cover up the flush tube that is opened when you use the lever. As the most movable part which goes up and down each time, it can get loose or break sooner than expected.

changing toilet fllapper

How do you replace the flapper valve to stop a Kohler toilet from running?

  1. Cut off the water supply and flush the toilet.
  2. Open the tank by removing the lid.
  3. Find the flapper at the bottom of the tank. It’s attached to the bottom of the overflow pipe.
  4. Disconnect it from the chain that lifts it at the flush.
  5. Remove the old flapper valve.
  6. Install the new one.

Flappers come in sizes from 2” to 4”. If you don’t know which flapper to buy to replace the old one, you can take a photo of it and show it to a manager in a plumber store, plus take measurements with a ruler, or bring the old one with you.

toilet flapper

Step-by-step guide on how to replace the fill valve

The reason why your Kohler toilet is running constantly might be caused by other issues with the fill valve. Kohler warns that if the water frequently drips into the toilet bowl, you might need to replace the valve. Worn-out fill valves also prevent the tank from getting full, making the flush weaker.

This is how to replace the fill valve in a Kohler toilet.

  1. Order the replacement valve. To detect the model you need, open the tank and see the color. If the cap of the valve is red or yellow, you need GP1083167. For white or other colors, it’s GP1138930. You’ll also need a flow restrictor kit for your valve.
  2. Turn off the water supply and flush the toilet.
  3. Place the bucket under the fill valve of the toilet to collect the excess water.
  4. Disconnect the supply pipe.
  5. Open the tank by removing the lid.
  6. Unthread the mounting nut on the bottom of the tank.
  7. Disconnect the refill hose.
  8. Remove the old valve.
  9. Choose the flow restrictor that has the same color as the old one from the kit and position it at the same height.
  10. Use the lock ring to match the height of the new valve.
  11. When matched, insert the new valve and fix it with the mounting nut from below.
  12. Connect the refill hose back to the valve in the tank.
  13. Reconnect the supply hose to the valve and turn on the water supply.

Take photos of the original construction before disassembling it.

toilet fill valve

FAQ About Fixing a Running Kohler Toilet

Kohler toilets are popular, and so are their owners and the questions they ask. Here I will address the most common of them.

How to replace the Kohler toilet tank gasket?

Access the tank as described above, remove the entire flush valve, and take the gasket off it. Buy an identical one and install it instead.

Why does my Kohler toilet run when another is flushed?

Probably, it’s just an acoustic effect. All the toilets in the building are connected with the water pipe system that (as a solid) transmits the sound better than the air does. This toilet might just resonate, but it seems like running. To make sure, you better check it.

Why does my toilet sound like water is running?

If it’s not the effect described above, then probably because it is. I recommend that you check it with food coloring.

Also read:

The Final Drop

So, if your Kohler toilet is running intermittently, you know how to stop it and save your time and money. Maybe, you will have to wait until your replacement parts are delivered, but it’s still more affordable.

In addition, you will get some experience that can help you with similar issues later. Do you have anything to add? A story about how you fixed your toilet or a recommendation on which Kohler toilets and mechanisms are more durable and easier to fix?

Other readers and I will be glad to hear your advice or stories in the comments.

Gerald Carpenter

My name is Gerald Carpenter and I am a professional plumber in the third generation. My father was a plumber, my grandfather was a plumber. I wish I had records on my other ancestors.

We will be happy to hear your thoughts

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