Oldsmobile 98 Headlight Bulb Size

Additional Notes

• The Oldsmobile 98 high beam headlight uses the 9005 bulb for 1991-1996 model years. The 9005 is a single-filament halogen bulb rated at 12V and 65W, fitted with a P20d base, and is governed by ANSI standards applicable in the US and Canada.
• The 9004 bulb, used in the Oldsmobile 98 for both high and low beam functions in 1988-1990, is a dual-filament halogen type with a P29t base rated at 12V and 65W/45W. Its dual-filament design means a single unit serves both beam functions, unlike the separate 9005 and 9006 pairing used in later years.
• The low beam headlight for 1991-1996 uses the 9006, a single-filament halogen bulb with a P22d base rated at 12V and 55W. Although the 9005 and 9006 share a similar physical profile, they have different base configurations and wattage ratings, making them non-interchangeable.
• From 1977-1986, the Oldsmobile 98 high beam position uses the H4651, a 4x6-inch rectangular sealed beam unit operating at 12V. Sealed beam units of this type house the filament, reflector, and lens as a single fused assembly, so the entire unit is replaced rather than an internal bulb.
• The low beam position for several years in the 1976-1986 range alternates between the H4652 and H4656, both 4x6-inch rectangular sealed beam units at 12V. The H4652 is a variant of the H4651, and these designations reflect differences in beam pattern and light output rather than physical form factor, so fitment must be matched precisely to the specified year.
• For 1958-1975, the high beam uses the H5001, a 4-inch square sealed beam unit at 12V, while the low beam uses the H5006, a 5.75-inch round sealed beam unit at 12V. These two units differ in both shape and size, and are not interchangeable with each other or with the rectangular sealed beam types used in later years.
• The 1953-1957 model years use the H6024 for both high and low beam positions. The H6024 is a 7-inch round sealed beam unit at 12V, and its use in both positions reflects the single-unit headlamp systems common to that era before separate high and low beam assemblies became standard.
• The 1950-1952 Oldsmobile 98 uses the H6006, a 5x7-inch rectangular sealed beam unit at 12V, for both high and low beam positions. Like all sealed beam types in these specifications, the H6006 is an ANSI-standardized unit replaced as a whole assembly.