SIERRA Internal Engine 18-0378 Powerhead Gasket For Mercury/Mariner Outboard Motor

Sierra Marine engine parts are designed to meet or exceed the performance of the Original Equipment Manufacturer (OEM) part they are intended to replace—and are backed by one of the best warranties in the marine aftermarket parts industry.

Complete engine repairs with quality gaskets from Sierra Marine.

Sierra gaskets are machined to perfectly match engine component mating surfaces, which gives trained technicians and DIY mechanics alike the confidence that the job will be done right the first time. For over 50 years, Sierra has supplied the best aftermarket parts in the marine industry—so boaters can enjoy the best of times on the water.

Key Features

• Engineered to meet or exceed manufacturer specifications
• Match OEM hole and port patterns for an exact fit
• OEM performance at a value price
• Often more readily available than OEM gaskets

Find the right part for your application.

For help in selecting the correct part for your engine application or to confirm this is the correct part, please visit the Sierra Engine Parts Selector, where you can search by OEM part number, Sierra part number, Brand, Engine model, Year, Horsepower, or Serial number.

Order with confidence!

The Sierra engine parts we sell are backed by Sierra’s Limited Customer Satisfaction Warranty—one of the best in the business. Sierra warranties their engine parts to be free of defects in workmanship and materials for the useful life of the product. Subject to limitations, if a Sierra product fails to comply with the Warranty, Sierra will repair or replace the defective product free of charge.