Parts for your 2013 Mazda Cx-5-Thermostat

2013 Mazda CX-5 Thermostat — purpose and servicing

Based on technical sources including the Mazda CX-5 (2013) Workshop Manual – Cooling System, the Mazda Electronic Parts Catalogue, and mainstream service databases (e.g., Autodata/Mitchell1), the 2013 Mazda CX-5 is fitted with a conventional wax‑pellet engine coolant thermostat located in the water outlet housing. Both Skyactiv‑G 2.0 petrol and Skyactiv‑D 2.2 diesel variants use a thermostat, the diesel additionally employs a separate thermostat in the EGR cooler circuit. Typical engine thermostat opening temperatures are in the 82–88°C range, confirming the part is relevant and used on this model.

The thermostat’s job is to help the CX‑5 warm up quickly and then hold a stable operating temperature. By staying shut when the engine is cold, it speeds warm‑up for smoother running, better fuel economy and lower emissions. Once up to temp, it meters coolant flow to the radiator so the engine doesn’t overcool on a chilly Kiwi morning or Aussie highway run. If it sticks open, the engine can take ages to heat up, the heater blows lukewarm air and the ECU may log P0128. If it sticks closed, overheating can occur rapidly.

For servicing, the thermostat is usually replaced only when there are symptoms or a fault code, but many workshops treat it as smart preventative maintenance every 8–10 years or around 150,000 km, especially if a coolant change is due. On Skyactiv‑G models, the thermostat is commonly integrated with the water outlet housing, so the assembly is swapped as a unit with a new O‑ring. Using Mazda‑approved FL‑22 long‑life coolant is a must, and correct bleeding prevents airlocks that can cause hot spots or erratic heater performance.

• Tell‑tale signs: slow warm‑up, fluctuating temp gauge, poor cabin heat, electric fans running too often, DTC P0128, or unexplained overheating.
• Good practice: replace the thermostat when doing major cooling‑system work, fit a new seal, and clean mating faces. Tighten bolts to the workshop‑manual spec—no over‑torquing.
• Bleeding tips: set the heater to HOT, fill with FL‑22, run the engine to operating temp, and top up after the system cools. A vacuum fill tool is ideal.

Diesel owners should note there may be two thermostats—engine and EGR cooler—so diagnosis and parts selection need to follow the Mazda workshop procedures.

Does the 2013 Mazda CX‑5 actually have a thermostat?

Yes. The Mazda Workshop Manual and EPC list an engine coolant thermostat in the water outlet housing on both Skyactiv‑G petrol and Skyactiv‑D diesel variants, with the diesel also using an EGR‑circuit thermostat.

What temperature does it open, and when should it be replaced?

The engine thermostat typically begins to open around 82–88°C. Replacement is recommended if there’s a P0128 code, overheating, slow warm‑up, or as preventative maintenance around 8–10 years/150,000 km when paired with a coolant service.

Where is it located and how hard is it to change?

It’s housed at the water outlet where the upper radiator hose meets the engine. On the diesel there can be a second unit in the EGR cooler loop. It’s a moderate DIY for experienced hands: drain coolant, remove the housing, fit the new thermostat and O‑ring, and bleed with FL‑22 coolant. Many owners prefer a workshop due to the bleeding procedure and access on tight engine bays.