Sierra Thermostat Gasket 18-0878-9, Replaces RM0003, Pack of 2

This Sierra thermostat gasket seals the thermostat housing on the engine, creating the seal needed to prevent coolant leaks at the mating surface between the thermostat cover and the engine block or housing. It is sold as part number 18-0878-9 and is packaged two gaskets per package, so you have a spare on hand or enough for a job that requires servicing more than one housing. Thermostat gaskets are a wear item that should be replaced any time the thermostat cover is removed, since reusing an old gasket can result in a coolant leak or an improper seal even if the gasket appears undamaged. This part is a direct equivalent for OEM number RM0003, making it a straightforward replacement when that OEM number is called for. Keeping a correct-fit thermostat gasket on hand is a low-cost way to avoid downtime during routine cooling system maintenance, thermostat replacement, or housing inspection.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0878-9
• Product Type: Thermostat Gasket
• Package Quantity: 2 gaskets per package
• Weight: 0.02 pounds
• UPC: 808282161828

Replaces (OEM)

• RM0003

Frequently Asked Questions

How many gaskets come in this package? Sierra part number 18-0878-9 is sold two gaskets per package, priced per package.

What OEM number does this thermostat gasket replace? This gasket replaces OEM number RM0003.

Is this gasket a genuine OEM part or an aftermarket equivalent? The 18-0878-9 is a Sierra-branded replacement gasket that is a direct equivalent for OEM number RM0003, not an OEM-branded part.

How much does this gasket weigh? The 18-0878-9 thermostat gasket weighs 0.02 pounds.

When should I replace the thermostat gasket? Any time the thermostat cover is removed for inspection or thermostat replacement, the gasket should be replaced rather than reused, since a used gasket can leak even without visible damage.

What is this gasket used for? It seals the thermostat housing to prevent coolant leaks at the mating surface between the thermostat cover and the engine, and is identified by Sierra part number 18-0878-9.

Can I buy just one gasket instead of the pack of two? Part number 18-0878-9 is sold and priced only as a package of 2 gaskets.

Does this gasket fit if my engine calls for OEM part RM0003? Yes, part number 18-0878-9 is the listed replacement for OEM number RM0003.

What is included when I order this part? Ordering 18-0878-9 gets you one package containing 2 thermostat gaskets.

What category of engine part is this? The 18-0878-9 gasket is categorized as an engine accessory, specifically a thermostat gasket.