MNJWS Timing Cover Gasket Set for GM V8 4.8L–6.2L — Direct-Fit Replacement for 12633904, Heat-Resistant Seal

MNJWS Timing Cover Gasket Set is a complete replacement gasket kit engineered to seal the timing cover to the engine block on 4.8L, 5.3L, 5.7L, 6.0L and 6.2L GM Vortec engines.

If your GM truck or SUV is showing oil seepage near the front of the engine, making unusual noises, or losing pressure around the timing cover area, the gasket set is the component most often responsible. This MNJWS kit is a direct-fit aftermarket alternative for OE part numbers 12633904 and TCS45993, designed to restore a reliable fluid and air seal and keep contaminants away from the timing gear and shaft.

How does this gasket set stop oil leaks at the timing cover?

The MNJWS gasket kit combines form-fit profiles and durable sealing materials to create a consistent compression surface between the timing cover and engine block. Proper installation prevents oil from weeping past the cover and collects where it can damage belts or accessories.

• Precision-cut gaskets matching factory contact points for even sealing
• Durable elastomer and composite materials resist heat and oil breakdown
• Includes all pieces needed to rebuild the timing cover joint for a single service

Which vehicles and engines are compatible with this set?

This kit is intended for GM vehicles equipped with Vortec V8 engines in the 4.8L through 6.2L range. Coverage includes many Chevrolet, GMC, Cadillac and Buick models from late-1990s through mid-2010s that use the referenced OE part number.

• Chevrolet: Silverado, Suburban, Tahoe, Avalanche, Camaro, Colorado, Express, Impala, Caprice
• GMC: Sierra, Yukon, Savana, Envoy, Canyon
• Cadillac Escalade and Buick Rainier when fitted with compatible V8 engines

Will this replace GM part 12633904 or TCS45993 exactly?

Yes — the MNJWS kit is made to replace GM 12633904 and aftermarket reference TCS45993, offering the same mounting points and sealing surfaces for a direct fit. Although it is an aftermarket product and not a GM-branded part, it is manufactured to meet or exceed OEM function and longevity expectations.

• Designed to match OEM dimensions and bolt patterns
• Manufactured from high-temperature resistant materials
• Backed by a 12-month limited warranty for peace of mind

How difficult is installation and what comes in the kit?

Installation is straightforward for anyone comfortable disassembling front-end engine components; follow a vehicle-specific repair manual for torque specs and sealing procedures. The kit contains all timing cover gasket components needed to reseal the timing cover during a single service event.

• Complete set of timing cover gaskets designed for one install
• Straightforward direct-replacement design reduces fitment adjustments
• Recommended: clean mating surfaces and replace seals as directed in service manual

Who is this for: The MNJWS Timing Cover Gasket Set is suited for professional mechanics, experienced DIY technicians, and fleet maintenance teams working on GM Vortec V8 engines (4.8L–6.2L) in trucks, SUVs, and vans. Choose this kit if you're replacing a leaking or damaged timing cover gasket, need a direct-fit substitute for OE 12633904/TCS45993, and want an aftermarket part built to withstand heat and prolonged exposure to oil.