Parts for your 2000 Honda Stream-Thermostat

2000 Honda Stream Thermostat

Technical sources confirm the 2000 Honda Stream is fitted with a conventional engine coolant thermostat. These include the Honda Stream RN1/RN3 service manual, Honda’s electronic parts catalogue, and mainstream technical data sets used in workshops (e.g., Haynes and Autodata for D17A and K-series engines). On D17A (RN1/RN2) and K20A (RN3) variants, the thermostat sits in the water outlet housing on the lower radiator hose side of the engine.

The thermostat’s job is to help the engine warm up quickly and then hold a steady operating temperature for good fuel economy and performance. It stays closed when the engine’s cold, then starts to open at roughly 78°C and is fully open by about 90°C. Genuine-style units are recommended: D17A commonly uses Honda 19301-PLC-315 with the matching seal, while K-series applications use 19301-PNA-003. Always confirm by VIN because build dates and markets can vary.

As part of regular servicing, it’s smart to keep an eye on cooling system health. The Stream should heat up to the middle of the gauge and stay there. If it runs cool on the open road, takes ages to get cabin heat, or swings hot then drops back, the thermostat could be the culprit. Likewise, unexplained overheating or coolant loss deserves attention.

• Suggested replacement: when symptomatic, during major cooling system work, or preventatively around 8–10 years/160,000 km.
• Coolant: Honda Type 2 premix (or equivalent long-life, silicate-free), stick with 50/50 and demineralised water if mixing from concentrate.

When replacing, let the engine cool fully. Drain enough coolant to get below the housing, remove the two housing bolts, and note the jiggle valve orientation (typically at 12 o’clock) on the new thermostat. Fit a fresh O-ring—no RTV needed—then torque the housing bolts to about 12 N·m. Refill, set the heater to HOT, and bleed air by idling until the fans cycle, top up the radiator and overflow bottle as bubbles purge. Many Streams don’t have a separate bleeder, so gently squeeze the upper hose to help purge. Check for leaks and go for a short road test, then recheck levels cold.

Using a quality OEM-spec thermostat and fresh coolant keeps the Stream running sweet, avoids hot-day dramas, and protects the head gasket and alloy components from thermal stress.

Where is the thermostat on a 2000 Honda Stream?

It’s in the water outlet housing where the lower radiator hose meets the engine. On D17A (RN1/RN2), that’s on the gearbox side of the block, on K20A (RN3), it’s tucked low on the intake side. Remove two bolts to access it.

What temperature should the Stream’s thermostat open?

OEM-spec units begin opening at about 78°C and are fully open by around 90°C. Sticking with the factory temperature rating keeps the ECU mapping, heater performance, and fuel economy on point.

Do they need bleeding after thermostat replacement?

Yes. Refill, set the heater to HOT, idle the engine until the radiator fan cycles, and top up as air purges. Squeezing the upper hose helps. Some cars have no dedicated bleeder, so patience and a proper cold recheck are key.