Parts for your 2010 Honda Odyssey-Thermostat

2010 Honda Odyssey Thermostat — what it does and when to replace it

Based on technical sources, including the Honda Service Manual for the 2005–2010 Odyssey (J35 V6) and Honda’s Electronic Parts Catalogue, the 2010 Honda Odyssey is fitted with a conventional wax‑pellet engine coolant thermostat housed at the water inlet where the lower radiator hose meets the engine. So yes — a thermostat is absolutely relevant and used on this model.

The thermostat’s job is to get the V6 up to proper operating temperature quickly, then keep it steady there. It stays shut while the engine warms, helping cabin heat arrive sooner and reducing wear and fuel use. Once warm, it opens to regulate coolant flow through the radiator, stopping overheating when working hard on hot Aussie or Kiwi days.

On a 2010 Odyssey, the thermostat also influences engine management. If it sticks open and the engine runs too cool, the ECU can flag a fault (often seen as a P0128 code), fuel economy drops, and the heater stays lukewarm. If it sticks shut, overheating, a hot smell under the bonnet, and coolant boil‑over can follow.

Thermostats aren’t a scheduled replacement item, but they’re smart to renew when there are cooling issues or while doing related jobs such as water pump and timing belt service (common around 160,000 km on the J35 V6). Use a quality thermostat with the correct temperature rating (Honda typically specifies an opening around the low‑80s °C) and always fit a new O‑ring.

• Common signs it’s time:
  • Slow warm‑up, poor heater, or fault code P0128
  • Overheating at speed or under load
  • Temperature gauge wandering or sudden spikes
• Service tips:
  • Work on a cold engine and catch old coolant responsibly
  • Thermostat sits in the water inlet at the lower radiator hose