Thermostat & Seals Kit – Fits Johnson/Evinrude 5-235 HP (Replaces 393659, 5005440, 8330720, 777260)

Product Details

This Thermostat & Seals Kit – Fits Johnson/Evinrude 5-235 HP is designed for a broad range of 2-Stroke & 4-Stroke outboard engines across various years. It ensures your engine maintains the correct operating temperature for optimal performance and longevity.

This kit serves as a direct cross-reference for Johnson/Evinrude part numbers 393659 and 5005440; Sierra 18-3543 and 18-3553; and OMC interchanges 8330720, 777260, 0377148, 434841, 378065, and 59434841.

• Engineered for direct replacement installation.
• Available in both Stainless Steel and Brass housing materials.
• Essential for routine cooling system maintenance.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Technical Specs

Product Type

Thermostat with Gasket/Seal Kit

Installation

Direct replacement

Fuel Type

Gasoline

Housing Material

Available in Stainless Steel or Brass versions

Operating Temperature

60°C/143°F (opening temperature)

Other Technical Attributes

For cooling system maintenance

What’s in the Box

• 1 x Thermostat (393659/5005440)
• 1 x Gasket/Seal Kit

Installation Notes

1. Disconnect the engine's battery before starting work.
2. Allow the engine to cool completely and drain the cooling system.
3. Locate and carefully remove the thermostat housing cover.
4. Take out the old thermostat and remove the old gasket or seal material.
5. Thoroughly clean the mating surfaces of the housing and cover.
6. Install the new thermostat, ensuring it is oriented correctly.
7. Position the new gasket or seal properly on the housing.
8. Reinstall the housing cover and tighten its fasteners to the manufacturer's recommended torque specifications.
9. Refill the cooling system with the appropriate coolant.
10. Reconnect the battery, start the engine, and carefully inspect for any leaks.

Troubleshooting & FAQ

Safety & Important Info

• Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.