Parts for your 2007 Honda Odyssey-Thermostat

2007 Honda Odyssey Thermostat — What it does and when to replace it

Technical sources confirm a thermostat is absolutely fitted to the 2007 Honda Odyssey. The Honda Odyssey 2005–2010 Service Manual (Cooling System section) details thermostat operation and replacement, and Honda’s genuine parts catalogue lists a direct-fit thermostat assembly for the J35 V6 (commonly referenced as P/N 19301-RAA-306). Aftermarket catalogues from major cooling system suppliers also specify a thermostat for this model, so it’s a relevant, everyday service item.

On this Odyssey, the thermostat is the little gatekeeper that gets the V6 up to proper operating temperature quickly, then keeps it there. It sits in the housing where the lower radiator hose meets the engine block on the timing belt side. When the engine’s cold, it stays shut to help it warm up faster, as the coolant reaches its designed temperature (typically around the high-70s to low-80s °C), it opens so coolant can circulate through the radiator. That steady temperature means better fuel economy, smoother running, strong cabin heat, and reduced engine wear.

Given the age of a 2007 Odyssey, the thermostat is a smart preventive replacement if the cooling system is being refreshed, especially when doing the timing belt and water pump. It’s inexpensive compared with the labour of going back in later, and it’s good practice whenever there are symptoms like:

• Slow warm-up or a temp gauge that never reaches mid-point
• Temperature swings or overheating under load
• Weak heater performance or coolant pushing into the overflow bottle

When replacing, always use a quality unit and a new O-ring, and refill with Honda Type 2 blue coolant (premix). With the engine cool, drain the radiator, remove the lower hose and housing, note the thermostat’s orientation, clean mating surfaces, fit the new O-ring, reinstall and tighten the housing bolts to factory spec (light fasteners, typically around 9–12 N·m), then refill and bleed air. Bleeding is as simple as idling with the heater on hot and the cap off until the fans cycle, topping up as needed. Dispose of old coolant responsibly.

Thermostats aren’t a set-interval item, but on an Odyssey of this vintage, replacing it every 160,000–200,000 kilometres or 7–10 years, or any time the cooling system is opened for major work, will keep the big family bus happy and dependable.

Popular questions about 2007 Honda Odyssey thermostats

Where is the thermostat on a 2007 Honda Odyssey?
It’s housed at the engine block where the lower radiator hose connects, on the timing belt side of the J35 V6. Access is from the front of the engine bay, remove the hose and two housing bolts to reach it. Always note the thermostat’s orientation before refitting.

What temperature does the Odyssey’s thermostat open at?
Factory-spec thermostats for the J35 V6 typically begin opening in the high-70s to low-80s °C range and are fully open around 90 °C. On the dash, that translates to the needle sitting steadily near the middle once warmed up, with the heater blowing nice and hot.

Should the thermostat be replaced with the timing belt and water pump?
Yes, it’s recommended. The extra part cost is small compared with the labour saved, and it helps avoid repeat visits if the old thermostat sticks later. It’s also a perfect time to renew coolant, radiator cap, and any tired hoses or clamps.