The Oldsmobile Fiesta high beam headlight uses H5001 or H6024 bulb size, while low beam headlight applications require H5006 or H6024 bulb size. The replacement chart covers 1953 through 1964 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 Oldsmobile Fiesta headlight specifications reference three sealed beam unit types across its model years: H5001, H5006, and H6024. All three conform to ANSI standards recognized in both the United States and Canada and operate on a 12V electrical system.
Sealed beam units integrate the filament, reflector, and lens into a single fused assembly. When a sealed beam fails, the entire unit requires replacement rather than an individual bulb.
The H6024 is a 7-inch round sealed beam unit. On the Oldsmobile Fiesta, it serves as both the high beam and low beam headlight for the 1953 and 1957 model years, meaning a single unit type handles both functions on those vehicles.
From 1958-1964, the Fiesta adopted a four-headlight arrangement using two distinct sealed beam types: the H5001 for high beam and the H5006 for low beam. These two units are not interchangeable with each other despite both operating at 12V.
The H5001 is a 4-inch square sealed beam unit used exclusively for the high beam position in the 1958-1964 model years. Its square form factor physically prevents substitution with the round units specified for other positions or years.
The H5006 is a 5.75-inch round sealed beam unit designated for the low beam position across the 1958-1964 model years. Although it shares a round form with the H6024, the two units differ in size and are not interchangeable.
The shift from the single H6024 unit in 1957 to separate H5001 and H5006 units in 1958 reflects the transition to a dual-headlight system, where dedicated high beam and low beam assemblies replaced a single combined unit.
Substituting an H5001 for an H5006, or vice versa, in the 1958-1964 model years would result in an incorrect fitment, as the square and round housings are physically incompatible with each other's mounting positions.