Mack CL Headlight Bulb Size

Mack CL headlight bulb sizes include H6024, H4651, and H5001 for high beam applications, along with H6024, H4652, and H5006 for low beam configurations, with each bulb size corresponding to specific vehicle specifications. The replacement chart covers 1991 through 1997 production years and details bulb size specifications for each model year.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

High Beam Headlight

Years	Bulb Size
1991-1997	H6024 (With 2 Round Headlamps)
	H4651 (With 4 Rectangular Headlamps)
	H5001 (With 4 Round Headlamps)

Low Beam Headlight

Years	Bulb Size
1993-1997	H6024 (With 2 Round Headlamps)
	H4652 (With 4 Rectangular Headlamps)
	H5006 (With 4 Round Headlamps)
1991-1992	H6024 (With 2 Round Headlamps)
	H4656 (With 4 Rectangular Headlamps)
	H5006 (With 4 Round Headlamps)

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). 7-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H6024
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4651
ANSI standard (US & Canada). 4-inch square sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H5001
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit, variant of H4651. Not a replaceable bulb — the entire unit is replaced. 12V.	H4652
ANSI standard (US & Canada). 5.75-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H5006
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4656

Other Locations

Additional Notes

The Mack CL (1991-1997) uses sealed beam headlight units across all three headlamp configurations. Sealed beam units integrate the filament, reflector, and lens into a single assembly, meaning the entire unit is replaced rather than an individual bulb.
All sealed beam types specified for the Mack CL operate at 12V and conform to ANSI standards recognized in both the United States and Canada.
The H6024 is a 7-inch round sealed beam unit serving as both the high beam and low beam in the two-round-headlamp configuration. Its dual-beam function means a single unit type covers both lighting modes on that configuration.
The four-round-headlamp configuration uses two distinct sealed beam types: the H5001, a 4-inch square unit, for high beam, and the H5006, a 5.75-inch round unit, for low beam. These two units are not interchangeable despite appearing in the same headlamp system.
The four-rectangular-headlamp configuration uses the H4651 for high beam across 1993-1997. The H4652, a variant of the H4651, serves the low beam role in that same period. Both are 4x6-inch rectangular sealed beam units, but their beam patterns differ and they are not interchangeable between positions.
In the four-rectangular-headlamp configuration for 1991-1992, the low beam unit is the H4656, a 4x6-inch rectangular sealed beam. From 1993 onward, this position shifts to the H4652. The high beam unit, H4651, remains unchanged across the full 1991-1997 range for that configuration.
The H4651, H4652, and H4656 all share the 4x6-inch rectangular sealed beam form factor. Because they occupy different beam positions and carry different ANSI designations, substituting one for another would not satisfy the original specification for a given position.
Three headlamp configurations are documented for the Mack CL throughout 1991-1997: two round headlamps, four round headlamps, and four rectangular headlamps. Each configuration requires a distinct set of sealed beam units, and bulb sizes are not shared across configurations.