The Kenworth K300 high beam headlight uses an H4651 bulb size, while low beam headlights require either H4652 or H4656 bulb sizes for proper illumination. The replacement chart covers vehicle production years from 1993 to 1997 with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Kenworth K300 uses H4651, H4652, and H4656 bulb types across its headlight positions, all of which are ANSI-standardized sealed beam units operating at 12V and sharing a 4x6-inch rectangular form factor.
All three bulb types are sealed beam units, meaning the lens, reflector, and filament are fused into a single assembly. When a filament fails, the entire unit requires replacement rather than an internal bulb swap.
The H4651 is the sole high beam specification for the Kenworth K300 across all listed model years, 1993-1997, indicating no variation in that position throughout the production span covered.
The low beam position shows a split between two bulb types: the H4652 is specified for 1993 and 1997, while the H4656 is specified for 1994-1996. These are distinct part numbers and are not listed as interchangeable despite sharing the same physical format.
The H4652 is described as a variant of the H4651. Both occupy the same 4x6-inch rectangular sealed beam format and operate at 12V, though they serve different beam functions and carry separate ANSI designations.
Because the H4651, H4652, and H4656 share the same physical housing format, physical fit alone does not confirm correct fitment. Each position and model year calls for a specific part number, and substituting one for another without verifying the ANSI designation risks incorrect beam output.
The ANSI standardization of all three bulb types means they conform to a defined performance and dimensional specification recognized across the United States and Canada, which supports cross-brand availability from multiple manufacturers.
The low beam specification for the K300 changed between 1993 and 1994, shifting from H4652 to H4656, and then returned to H4652 for 1997, making the model year a necessary reference point when sourcing a low beam replacement.