Hino SF17 high beam headlight bulbs use H4651 size while low beam headlight bulbs use H4656 or H4652 size. The replacement chart covers 1988 to 1991 vehicle production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H4651, H4652, and H4656 are all ANSI-standardized sealed beam units used across the Hino SF17 headlight system. ANSI standardization means these units conform to a fixed set of electrical and optical specifications recognized throughout the United States and Canada.
All three bulb types share the same 4x6-inch rectangular sealed beam form factor and operate at 12 volts. In a sealed beam unit, the filament, reflector, and lens are fused into a single glass envelope, meaning the entire unit is replaced rather than an internal bulb.
The Hino SF17 uses the H4651 exclusively for the high beam headlight across all four model years from 1988-1991, making it the most consistent fitment in the specification set.
The H4652 is described as a variant of the H4651. Despite sharing the same form factor and voltage rating, the two are distinct ANSI part numbers and are not listed as interchangeable within these specifications.
The low beam headlight position on the Hino SF17 does not use a single bulb type across all years. The 1990-1989 model years use the H4652, while the 1988 and 1991 model years use the H4656, indicating that the same physical position can require different sealed beam units depending on the model year.
Because the H4651 and H4656 share the same physical size and voltage but carry different ANSI designations, substituting one for the other is not supported by these specifications. ANSI sealed beam codes encode specific beam pattern and luminous intensity characteristics, not just physical fit.