• Honda 19301-PNA-003 Genuine Thermostat Assembly
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Honda

Honda 19301-PNA-003 Genuine Thermostat Assembly

Honda 19301-PNA-003 Genuine Thermostat Assembly

$84.97
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✔ Genuine Honda 19301-PNA-003 Thermostat Assembly — OEM Part
✔ Fitment: 2002–2006 Acura RSX, 2002–2005 Honda Civic Si, and 2002–2006 Honda CR-V with K20A2, K20A3, and K24A1 engines
✔ Direct replacement for factory thermostat assembly — no modifications required
✔ Manufactured to Honda’s original specifications — 78°C (172°F) opening temperature
✔ Complete assembly — includes thermostat, aluminum housing, and O-ring gasket in one unit
✔ Genuine OEM quality — same assembly your engine came with from the factory

 

Genuine Honda 19301-PNA-003 Thermostat Assembly — for K-Series Engines

Engine overheating because the thermostat is stuck closed, or running cold because it is stuck open — these are the two common failure modes that signal it is time to replace your thermostat assembly. This genuine Honda part is the complete thermostat assembly for select K-series engines, including the thermostat itself, the aluminum housing it sits in, and the O-ring gasket that seals it to the engine .

This is a factory-original Honda thermostat assembly (OE part number 19301-PNA-003). It is the same assembly your engine came with from the factory, designed to bolt on as one complete unit without the need to buy pieces separately .

When to Replace

• Engine overheating (thermostat stuck closed)
• Engine running cold or never reaching operating temperature (thermostat stuck open)
• Temperature gauge fluctuating or climbing into the red
• Heater not blowing hot air
• Check engine light with P0128 (coolant temperature below regulating temperature)

Product Details & Highlights

• ✔ Genuine Honda OEM — not an aftermarket or Chinese replica
• ✔ Complete assembly — thermostat, aluminum housing, and O-ring gasket included
• ✔ Direct bolt-on replacement — no drilling or modifications needed • ✔ Aluminum housing with integrated thermostat — same as factory original • ✔ Manufactured to Honda’s strict quality standards
• ✔ Backed by Honda’s manufacturer warranty (minimum 12 months)

Package Contents

• 1 × Genuine Honda 19301-PNA-003 thermostat assembly
• 1 × O-ring gasket (included)

FAQ

FAQ

Is this a genuine Honda part or a copy?
This is 100% genuine Honda OEM — in original factory packaging with the Honda part number printed on the label. It is not an aftermarket brand or a replica .

Does this fit my 2004 Acura RSX?
Yes — the 2004 RSX with the K20A2 or K20A3 engine uses this thermostat assembly. We recommend verifying with your VIN .

Does this fit my 2005 Honda Civic Si?
Yes — the 2005 Civic Si (EP3) with the K20A3 engine is listed as compatible .

Does this fit my 2003 Honda CR-V?
Yes — the 2003 CR-V with the K24A1 engine is listed as compatible .

Can I reuse the old housing?
No — this is a complete assembly that includes a new aluminum housing and O-ring. The old housing can corrode or crack over time, and the O-ring gets hard and stops sealing. Using the complete assembly ensures everything is new and leak-free .

Does this come with a new gasket?
Yes — the O-ring gasket is included with the assembly .

How do I install this thermostat?
The assembly bolts on as one unit. Remove the old thermostat housing, clean the mating surface, and install the new assembly with the new O-ring. Refill the cooling system and bleed air from the system . We recommend consulting your vehicle's service manual for the correct procedure.

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