Sierra 18-3730 Lock Nut - Replaces OMC/Volvo Penta 3852648

The Sierra 18-3730 is a metal lock nut engineered as a direct replacement for OMC and Volvo Penta part 3852648. It is built to meet or exceed the quality of the original equipment part it replaces, making it a reliable choice for boat owners performing maintenance or repairs who want factory-equivalent fit and performance without sourcing a discontinued OEM part.

This lock nut is a fully threaded metric fastener with a hex head and a machined exterior finish. Its metal construction, using alloy steel and stainless steel, is designed to resist the corrosive marine environment while providing the clamping strength required for secure fastening. As a lock-style nut, it is intended to stay put under vibration, an important trait for hardware used on boats.

The Sierra 18-3730 falls under Sierra's Volvo Penta prop nut and washer offerings, reflecting its common use in propeller hardware and related assemblies where a dependable, corrosion-resistant lock nut is needed. Every Sierra part is manufactured to be interchangeable with the original equipment number it lists, so installation follows the same procedure as the OEM nut it replaces.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3730
• Category: Volvo Penta Prop Nuts & Washers
• Weight: 0.02 pounds
• Material: Metal
• Metal Type: Alloy Steel, Stainless Steel
• Fastener Type: Lock
• Thread Type: ISO Metric
• Thread Style: Metric
• Thread Coverage: Fully Threaded
• Thread Class: Class 2A
• Screw Head Style: Hex
• Exterior Finish: Machined
• Finish Type: Brushed
• Package Dimensions: 5.13 x 4 x 0.5 inches
• UPC: 808282103347

Fitment

Universal marine fastener; consult the Replaces (OEM) list below to confirm compatibility with your specific application.

Replaces (OEM)

• 3852648

Frequently Asked Questions

What does the Sierra 18-3730 lock nut replace? The Sierra 18-3730 is a direct replacement for OMC and Volvo Penta part number 3852648.

Is the Sierra 18-3730 the same as the original OMC 3852648 nut? Yes, the Sierra 18-3730 is manufactured to meet or exceed the quality of the original OMC 3852648 part it replaces, so it installs and functions the same way.

What is the Sierra 18-3730 lock nut made of? It is made of metal, specifically alloy steel and stainless steel, with a machined exterior finish for corrosion resistance in marine environments.

What thread type does the 18-3730 lock nut use? The 18-3730 uses an ISO metric thread, fully threaded with a Class 2A thread fit.

How much does the Sierra 18-3730 lock nut weigh? The Sierra 18-3730 lock nut weighs 0.02 pounds.

What style of nut is the 18-3730? It is a lock-style nut with a hex head, designed to resist loosening from vibration once tightened.

What is the 18-3730 lock nut typically used for? Sierra lists the 18-3730 under its Volvo Penta prop nuts and washers category, making it suited for propeller hardware and similar fastening applications.

Will the Sierra 18-3730 fit hardware originally equipped with Volvo Penta 3852648? Yes, the 18-3730 is a direct replacement for Volvo Penta part 3852648 as well as the equivalent OMC number.

How many lock nuts come in one Sierra 18-3730 package? The Sierra 18-3730 is sold as a single lock nut.

What finish does the Sierra 18-3730 lock nut have? It has a machined, brushed exterior finish.