
Kohler GP1078441
Score: 85/100
Kohler GP89825
Score: 75/100Rankings

The Kohler GP1078441 is a genuine OEM replacement flapper designed specifically for Kohler two-piece toilets featuring Class Five flushing technology. Its key strength is the precise 3.25-inch rubber seal that effectively prevents phantom flushes and maintains high-efficiency performance. However, it is incompatible with non-Kohler models and may degrade faster in hard water environments.

The Kohler K-GP89825 is a genuine 2-inch replacement flapper designed exclusively for the Kohler Portrait one-piece toilet model K-3357. It features a shark-fin design with an adjustable chain and is constructed from premium, corrosion-resistant rubber to ensure durability. This part serves as a direct replacement for several discontinued flapper models, ensuring proper function for the specified model.
| Attribute | ![]() | ![]() |
|---|---|---|
3.25 inchesbest | 2 inches | |
1 countbest | 1 countbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Material & Durability(1) | ||
Seal Type | Rubber | Shark-fin |
Design & Features(3) | ||
Chain Adjustability | false | true |
Installation Type | Direct Replacement | Standard |
Flapper Type | Standard Flapper | Shark-fin |
Packaging & Support(1) | ||
Warranty Period | 1 Year Limited | 1-year limited |
Compatibility & Fit(4) | ||
Flush Valve Compatibility | Kohler Class Five | 2 inches |
Flapper Diameter (inches) | 3.25 inches | 2 inches |
Toilet Type Compatibility | Two-Piece | Kohler Portrait K-3357 |
Flush Valve Size | 3.25 inch | 2 inches |


Products in the top-left offer the best value (high score, low price).

Plumbing experts and editors from sites like Ferguson and CPE Supply highly recommend this part as the definitive OEM replacement for Class Five systems. They highlight its precise 3.25-inch seal as critical for preventing phantom flushes and its durable rubber construction for resisting corrosion.
Everyday consumers generally report high satisfaction, with many noting that the flapper perfectly fits their Kohler models and restores the toilet to like-new flushing performance. Common praise includes the ease of installation and the elimination of running toilet noises.

Professional reviewers and editors do not provide specific quotes or in-depth testing results for this product. Retailer descriptions and Kohler service documentation emphasize its status as a genuine OEM part, highlighting the reliability of its premium materials and USA manufacturing. It is confirmed as the direct replacement for older flappers in Portrait toilets, ensuring proper function for the specified model.
Consumer feedback is limited, with Home Depot listing 37 reviews but lacking specific quoted praise or complaints. Common implied praise centers on the reliable fit and durability for K-3357 owners. Recurring issues in Q&A sections involve frequent compatibility questions, with confirmations that the part does not fit non-Portrait models. There are no widespread complaints regarding leaks, short lifespan, or installation difficulties.
“Perfect fit for my Kohler Cimarron-flush like new!”

“No more running toilet; lasted 2 years in hard water”

“Installed in 2 minutes, chain included.”


