Honda Thermostat Assembly 19301-RNA-315 OEM Marine Engine Temperature Control, Corrosion-Resistant

Honda 19301-RNA-315 is the genuine OEM thermostat assembly that maintains proper engine temperature for compatible Honda outboard motors.

Keep your Honda marine engine running in its ideal temperature band with this factory-original thermostat assembly. Built to the same specifications used in Honda manufacturing, the 19301-RNA-315 replaces worn or failed thermostats to help protect engine components, improve warm-up time, and support consistent performance on the water. This is an authentic OEM part, not an aftermarket substitute, and it fits Honda models specified by the part number.

How does this thermostat assembly affect engine temperature control?

The thermostat opens and closes in response to coolant temperature to regulate flow through the cooling system. When cold, it stays closed to speed warm-up; once the coolant reaches the designed threshold, it opens to allow circulation and prevent overheating. Using the correct OEM unit ensures the calibrated opening temperature and reliable operation over time.

• Factory-calibrated opening temperature for precise control
• Designed to reduce thermal stress during warm-up
• Resistance to corrosion from marine environments
• Direct replacement for vehicles requiring 19301-RNA-315

Will this Honda thermostat fit my engine and how do I confirm compatibility?

Compatibility is determined by the engine model and serial numbers referenced in Honda parts manuals. Check your engine’s parts diagram or contact a Honda dealer with your model/year to confirm that 19301-RNA-315 is correct. Installing the exact OEM part avoids fitment problems and eliminates guesswork associated with aftermarket alternatives.

• Compare part number 19301-RNA-315 with your parts manual
• Provide engine model and serial number to confirm fit
• OEM form factor ensures proper sealing and mounting
• Dealer assistance available for verification

What are the visible differences between this OEM thermostat and aftermarket options?

Genuine Honda thermostats are produced to factory quality standards and materials, so dimensions, valve action, and corrosion resistance match original specifications. Aftermarket units may vary in calibration, materials, or finish, which can affect longevity and performance. Choosing the OEM assembly minimizes risk of premature failure or improper temperature regulation.

• Exact OEM dimensions and mounting points for trouble-free installation
• Materials and finishes selected for marine durability
• Consistent thermal calibration versus variable aftermarket tolerances
• Backed by Honda part identification and dealer sourcing

How should I install and maintain the thermostat for best results?

Installation should follow Honda service instructions, including proper gasket sealing, torque specifications, and coolant system bleed procedures. Routine inspection during scheduled maintenance helps catch leaks, corrosion, or sticking early. Replace the thermostat when symptoms like extended warm-up, overheating, or coolant leaks indicate failure.

• Use Honda-recommended gaskets and torque specs
• Bleed the cooling system of air after installation
• Inspect for corrosion or seal degradation during service
• Replace if temperature regulation or coolant flow is compromised

Who is this for: Boaters and marine technicians who operate or service Honda outboard engines and require an exact, factory-grade replacement part. If you need reliable temperature control, peace of mind from OEM fitment, and long-term durability in salt or freshwater conditions, the Honda 19301-RNA-315 thermostat assembly is designed for your maintenance needs.

Features:

• genuine oem factory part
• exact fit
• durable
• best in quality
• this is not an aftermarket part
• OEM