Honda genuine thermostat 19301-rna-315 Accord Civic CR-V

Honda OEM Thermostat 19301-RNA-315 – with gasket (replaces 19301-RNA-305)

The Honda OEM thermostat 19301-RNA-315 is a factory-designed cooling system component used in Honda petrol engines from the R-series (R18 / R20). It ensures precise thermal control, stable operating temperature and correct warm-up time. This model replaces the earlier thermostat 19301-RNA-305 and offers full compatibility with the same engines and models.

Manufactured to strict Honda standards, the thermostat opens and closes at exact temperature values required by the ECU, preventing typical issues such as underheating, temperature fluctuation, weak cabin heating and increased fuel consumption. The kit includes the original thermostat gasket, ensuring proper sealing after installation.

Advantages of the Honda OEM thermostat 19301-RNA-315

• Precise temperature control calibrated for R18 and R20 engines
• Stable thermal performance in city and highway driving
• Factory-grade durability and resistance to high coolant temperature
• Eliminates issues common with aftermarket thermostats (incorrect opening temperature)
• Includes the correct Honda gasket for a perfect seal

Compatibility – supported Honda models

Honda Accord – R20A3

• Honda Accord 4D (2009–2015) – 2.0 R20A3
• Honda Accord Tourer (2009–2015) – 2.0 R20A3

Honda Civic – R18 engines (R18A2, R18Z1, R18Z4)

• Honda Civic (2006–2011) – 1.8 i-VTEC
• Honda Civic (2012–2017) – 1.8 i-VTEC

Honda CR-V – R20 engines (R20A2, R20A9)

• Honda CR-V (2007–2012) – 2.0 i-VTEC
• Honda CR-V (2013–2018) – 2.0 i-VTEC

Honda FR-V – R18A1

• Honda FR-V (2007–2009) – 1.8 i-VTEC

Symptoms of a failing thermostat

• Engine takes a very long time to warm up
• Temperature gauge fluctuates while driving
• Weak cabin heating in winter
• Increased fuel consumption
• Engine overheating in traffic or under load

FAQ – Honda Thermostat 19301-RNA-315

Does 19301-RNA-315 replace 19301-RNA-305?
Yes. Honda confirms full compatibility – 19301-RNA-315 is the updated service version of 19301-RNA-305.

Should the gasket be replaced as well?
Yes. The thermostat is supplied with the correct OEM gasket and both should be replaced together to ensure proper sealing.

How often should the thermostat be replaced?
Typically every 150,000–200,000 km or when you notice temperature irregularities, poor heating or overheating.

Is a genuine OEM thermostat better than aftermarket?
Yes. Aftermarket thermostats often open at incorrect temperatures, which can cause poor engine performance, higher fuel consumption and unstable operating temperature. An OEM Honda thermostat guarantees correct calibration and long-term reliability.

Does this thermostat fit every R18 and R20 engine?
It covers most R18/R20 applications listed above, but for 100% certainty we always recommend verification by VIN or using Honda’s EPC.

Summary:
The Honda 19301-RNA-315 thermostat is the most reliable choice for R-series engines. It restores proper cooling system operation, protects the engine against overheating and underheating, and ensures efficient, economical driving in everyday use.