Sierra 18-0939-9 Upper Gearcase Dipstick Gasket - Replaces OMC 315189 - Pack of 2

The Sierra 18-0939-9 Upper Gearcase Dipstick Gasket is a replacement gasket for the upper gearcase dipstick opening on applicable outboard and sterndrive gearcases, sold as a pack of 2 for stocking spares or servicing multiple units. It is designed to seal the dipstick tube against the gearcase housing, helping prevent gear lubricant from seeping out around the dipstick during normal operation and while checking gearcase oil level. Sierra manufactures this gasket to meet or exceed the quality of the original equipment part it replaces, giving installers a reliable option when performing gearcase service, dipstick replacement, or general lower-unit maintenance. Because the gasket is a wear item that can harden, compress, or tear over time, replacing it whenever the dipstick is removed for service helps maintain a proper seal and avoid oil loss. The 18-0939-9 gasket is interchangeable with OMC part number 315189, making it a straightforward like-for-like replacement for technicians and boat owners who already have the OMC part number from their service manual or parts diagram. Its small size and low weight make it an easy, low-cost addition to a maintenance parts kit alongside other gearcase seals and gaskets.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-0939-9
• Description: Upper Gearcase Dipstick Gasket
• Package Quantity: Pack of 2
• Weight: 0.01 pounds
• UPC: 808282162047
• OEM Cross-Reference: OMC 315189

Fitment

Fits applications originally using OMC gearcase gasket part number 315189. Check your dipstick tube gasket location against this part number before ordering.

Replaces (OEM)

• OMC 315189

Frequently Asked Questions

What does the Sierra 18-0939-9 gasket fit? The Sierra 18-0939-9 Upper Gearcase Dipstick Gasket is designed as a direct replacement for OMC part number 315189, so it fits any application that originally used that OMC gasket at the upper gearcase dipstick opening.

Is the 18-0939-9 gasket the same as OMC 315189? Yes, Sierra part 18-0939-9 is interchangeable with OMC 315189 and is built to meet or exceed the quality of that original equipment gasket.

How many gaskets come in a pack? The Sierra 18-0939-9 is sold as a pack of 2 upper gearcase dipstick gaskets.

How much does this gasket weigh? Each package of the Sierra 18-0939-9 gasket weighs 0.01 pounds.

When should I replace the upper gearcase dipstick gasket? The dipstick gasket should be replaced any time the dipstick is removed for gearcase service, since the Sierra 18-0939-9 gasket can lose its seal after being disturbed or after prolonged use, leading to oil seepage around the dipstick.

Is this a genuine Sierra part or an aftermarket copy? The 18-0939-9 is a genuine Sierra International part manufactured to meet or exceed the original equipment specification of OMC 315189, not a generic aftermarket substitute.

What is the UPC for the Sierra 18-0939-9? The UPC for the Sierra 18-0939-9 Upper Gearcase Dipstick Gasket is 808282162047.

What is included when I order this part? Ordering the Sierra 18-0939-9 gets you a pack of 2 upper gearcase dipstick gaskets; no other hardware or tools are included.

Can I use this gasket for general gearcase maintenance? Yes, the Sierra 18-0939-9 gasket is commonly used during routine gearcase oil checks and service any time the dipstick is pulled and reinstalled.

Does Sierra list any other cross-reference numbers for this gasket? The only cross-reference listed for the Sierra 18-0939-9 gasket is OMC part number 315189.