Parts for your 2006 Honda Stream-Thermostat housing

2006 Honda Stream thermostat housing: what it does and how to look after it

Yes, the 2006 Honda Stream uses a thermostat housing. Technical sources such as the Honda Stream Workshop Manuals and the Honda Electronic Parts Catalogue (EPC) for RN1/RN3 (D17A/K20A) and RN6 (R18A/R20A) variants list a thermostat plus a dedicated housing/water outlet assembly, sealing O-ring, and related sensors. That makes the thermostat housing a key cooling-system component on this model.

The thermostat housing is the gateway that directs coolant between the engine and radiator. It holds the thermostat, provides hose connections, and on many engines carries the coolant temperature sensor. On the Stream’s D17A and K20A engines it’s mounted low on the engine and ties into the lower radiator hose, on the later R18A/R20A engines it’s a compact plastic or alloy unit at the transmission end of the block. Honda documentation often calls it the “water outlet” or “thermostat cover”.

For owners, this part matters because it helps the engine warm up quickly and then stay bang on its designed operating temperature. A sticky thermostat or a warped, brittle housing can cause slow warm-up, overheating under load, poor heater performance, or creeping coolant loss. During routine servicing, it’s smart to inspect the housing for hairline cracks, seepage around the O-ring, and chalky residue at hose necks or the temperature sensor.

Replacement is straightforward but benefits from a methodical approach:

• Use a quality housing (OEM or reputable aftermarket) and always fit a new thermostat and O-ring together.
• Clean the mating surfaces carefully, avoid gouging the alloy. Light corrosion should be removed so the O-ring can seal properly.
• Tighten fasteners evenly to the manufacturer’s spec and reattach hoses with sound clamps.
• Refill with Honda Type 2 (blue) long-life coolant mixed to spec, and bleed the system with the heater on hot to purge air.
• Run the engine to operating temp and confirm fan cycling, steady gauge behaviour, and a toasty heater.

There’s no fixed kilometre-based schedule for the housing itself, but if the vehicle is older or past 150,000–200,000 km, proactively renewing the thermostat, O-ring and a tired plastic housing can save a roadside drama. Any time the housing shows cracking, distortion, or repeated leaks, replacement is the right call. These points align with Honda service literature practices and part listings used by dealers and independent specialists.

Where is the thermostat housing on a 2006 Honda Stream?

On D17A (RN1) engines it sits beneath the intake side of the head, feeding the lower radiator hose. On K20A and the later R18A/R20A engines (RN3/RN6), it’s on the gearbox end of the block, low and forward with the lower radiator hose attached. Access varies by engine, but it’s always near the lower hose connection.

What are common leak points on the housing?

Typical spots are the O-ring seal to the block, the hose necks (especially if the plastic has gone brittle), and around the coolant temperature sensor. Any white crusty deposits or sweet coolant smell under the bonnet are cues to inspect the housing and clamps closely.

Do I have to use Honda Type 2 coolant after replacement?

It’s strongly recommended. Honda Type 2 blue coolant is formulated for the alloy and seals used in these engines and helps reduce corrosion and scale. Mixing types can shorten coolant life and may affect seal performance, so stick with the correct fluid and bleed the system properly.