Replacement Oil Filler Cap with Dipstick Set of 2 for Honda GX340 GX390 Engines Durable Sealed Cap with O-Ring and 9 Inch Dipstick for Small Engine Lawn Mowers

Core Benefits & Key Features

01.Engineered Thread Match for GX340 & GX390 Platforms

Each cap is machined to the original thread pitch and seat geometry of GX340 and GX390 engines, allowing the assembly to seat flush without cross-threading.The result is a secure fit that holds through vibration, transport, and hours of continuous operation.

02.Integrated 9-Inch Dipstick for Accurate Oil Level Reads

The attached measurement rod extends 9 inches and features crisp, easy-to-read level markings that align with factory fill specifications.No separate tool required—remove, wipe, reinsert, and read in seconds, even in low light or tight engine bays.

03.Heat-Resistant Thermoplastic Cap Body

The cap is formed from a durable, gasoline- and oil-resistant polymer that maintains its shape under sustained engine heat.The surface is finished with a raised OIL identifier for fast visual confirmation during routine maintenance.

04.Embedded Rubber Sealing Ring

A pliable O-ring sits within the cap channel to form a positive seal against crankcase pressure and vapor.This helps prevent oil seepage around the filler neck and reduces the risk of contamination from dust and debris.

05.Knurled Grip Profile for Confident Handling

The cap body includes a textured grip zone that provides positive purchase when tightening or loosening, even with oily or gloved hands.No tools required for installation or routine oil checks.

06.Two Complete Assemblies Per Order

Every set includes two full cap-and-dipstick units, offering a practical spare for seasonal service or the ability to outfit a second engine without placing a second order.Packaged individually to protect threads and measurement faces during transit.

Why Choose This Replacement Set

Factory original parts are not always available when you need them, and generic caps rarely match the thread pattern or sealing surface your engine depends on.This aftermarket set is built around the known specifications of the GX340 and GX390 platforms, with attention paid to thread tolerance, cap wall thickness, and dipstick length.Each assembly is inspected for clean thread formation and consistent marking placement before packing.The included sealing ring is retained in a dedicated channel rather than simply pressed into place, helping the cap maintain its seal through repeated removal cycles.

Where bargain alternatives cut corners on material grade or omit the dipstick entirely, this set arrives complete and ready to install—no extra parts, no modifications, no second trip to the hardware store.

Daily Usage & Lifestyle Application

Saturday morning mowing.​ Before the first pass of the season, check your oil level with the integrated dipstick, top off as needed, and head out knowing the cap will hold its seal through the entire cut.

Equipment turnover between seasons.​ When storing a mower, tiller, or generator for winter, verify fluid levels with a clean, legible dipstick and replace a weathered cap before the long idle period begins.

Multi-machine households.​ Keep a spare assembly on hand for a second piece of small-engine equipment—ideal for households that maintain both a push mower and a walk-behind tiller on the same engine platform.

Field service and trailering.​ A properly seated filler cap helps prevent slow seepage during transport, keeping your trailer bed and storage space clean.

Routine maintenance between jobs.​ For landscape contractors and property managers, a readable dipstick and reliable cap are the foundation of a quick pre-shift inspection routine.

Product Specifications

Premium Quality & Safety Guarantee

Every assembly in this set is produced to documented dimensional specifications and inspected prior to shipment. The cap body is tested for thread integrity and sealing-surface consistency, while the dipstick rod is verified for straightness and marking clarity. This product is sold as a functional aftermarket replacement component and is not affiliated with or endorsed by Honda Motor Co., Ltd. or any original equipment manufacturer.