ACDelco RTV Engine Sealant GM Original Equipment 5.3 oz Cartridge — High-Viscosity, Quick-Curing Liquid Gasket

ACDelco GM Original Equipment 10-2010 RTV Engine Sealant (12378521) is a high-viscosity, quick-curing gasket maker formulated to seal oil- and coolant-exposed engine joints and components.

Made to GM OE standards and supplied in a 5.3 oz cartridge for use with common caulking guns, this RTV (room-temperature-vulcanizing) sealant bonds to metal and many composite surfaces, forming a durable gasket where preformed gaskets are worn or unavailable. It cures as it reacts with air, allowing for rapid assembly and minimal downtime. Technicians and home mechanics rely on ACDelco parts for fit and consistency across a broad range of engine sealing tasks.

What engine parts can I use this sealant on?

This RTV is suitable for numerous engine joints where a dependable liquid gasket is required. It adheres well to aluminum, cast iron, and most polymer surfaces commonly found in modern engines.

• Oil pans and sump seams
• Front and rear timing covers
• Valve/camshaft covers and cam seals
• Intake and exhaust manifold ends, t-joints, and corners

How fast can I reassemble and run the engine after applying the sealant?

The product is designed for relatively quick handling: it skins and begins to cure when exposed to air, enabling reassembly in a short period. In many cases, the engine may be refilled with oil or coolant immediately after torqueing fasteners, but full cure time depends on bead thickness and ambient conditions.

• Quick skin formation on exposure to air
• Short handling time allows fast reassembly
• Full cure time varies with bead size and temperature

What makes this ACDelco sealant different from other RTVs?

This GM Original Equipment-branded RTV is formulated to meet factory-level specifications for sealing engine components, balancing viscosity for easy application with enough body to stay in place on vertical surfaces. It’s engineered for automotive conditions where oil and coolant contact is expected.

• Higher viscosity for controlled bead placement
• Cures to a resilient gasket when exposed to air
• OEM-quality formulation tuned for engine environments

How should I apply and prepare surfaces for best results?

Clean, dry surfaces ensure the strongest bond; remove old gasket material, oil, grease, and coolant residue before applying. Use a steady bead from a caulking gun and allow appropriate cure time for thicker applications.

• Scrape and clean mating surfaces thoroughly
• Apply even continuous bead; avoid excessive overfill
• Torque fasteners to manufacturer specs after initial cure

Who is this for: Mechanics and DIYers who need a reliable, OEM-grade liquid gasket for automotive engine repairs—especially when replacing or repairing oil pans, covers, manifolds, or other engine joints. This 5.3 oz cartridge fits standard dispensers, making it practical for workshop use and at-home repairs where a precision, durable seal is required.