Parts for your 2001 Daihatsu Gran move-Thermostat

2001 Daihatsu Gran Move Thermostat — what it does and when to replace it

Is a thermostat actually used on a 2001 Daihatsu Gran Move? Yes. Technical references including the Daihatsu Gran Move/Pyzar (G3-series) Workshop Manual — Cooling System section, the Daihatsu Electronic Parts Catalogue (Cooling Group 16: Thermostat/Water Inlet), and dealership service data (for HC‑EJ and K3‑VE engines) all specify a wax‑pellet thermostat fitted in a small housing where the radiator hose joins the engine. On these models it’s typically at the water inlet on the block (lower radiator hose), with an O‑ring seal and a jiggle valve oriented up.

On the 2001 Gran Move, the thermostat’s job is to get the engine up to operating temperature quickly, then hold it there. It stays shut when cold so the engine warms up fast, improving fuel economy and heater performance. Once coolant reaches roughly the spec’d opening temperature (commonly around 82–88°C for these Daihatsu units per workshop data), it opens and lets coolant flow through the radiator to keep temps steady. A lazy or stuck thermostat can cause slow warm‑up, fluctuating temperature, overheating at speed, or weak cabin heat.

As part of regular servicing, it’s smart to inspect for leaks around the housing and keep the cooling system fresh. Thermostats aren’t strictly a time‑based replacement item, but many owners change them proactively when doing a coolant service or if any cooling issues pop up. Use the correct temperature‑rated thermostat and a new gasket/O‑ring as per Daihatsu specs.

• Typical replacement steps: let the engine cool fully, drain enough coolant to drop the level below the housing, remove the hose and housing, note the thermostat orientation (jiggle pin up), fit the new unit with a fresh seal, reassemble and torque the small housing bolts lightly and evenly (about 8–12 N·m if spec isn’t at hand).
• Refill with the correct ethylene‑glycol coolant (silicate‑free/long‑life type used by Daihatsu/Toyota), set the heater to HOT, bleed out air, and check for leaks. Avoid mixing red long‑life with other colours.
• Quick check at home: from cold, the upper hose should stay cool until the gauge climbs, it’ll warm rapidly when the thermostat opens. For a definitive test, remove and heat the thermostat in water with a thermometer to see if it opens at the marked temp.

If the Gran Move is taking ages to warm up, runs hot on the motorway, or the temp gauge wanders, a fresh thermostat and coolant are inexpensive peace of mind.

Popular questions about the 2001 Daihatsu Gran Move thermostat

Where is the thermostat located on a 2001 Gran Move?
It sits in a small alloy housing where a radiator hose meets the engine. On these engines it’s typically at the water inlet on the block, connected to the lower radiator hose. The housing is held on with two small bolts and sealed by an O‑ring.

What temperature does the Gran Move thermostat open?
Workshop information for Daihatsu HC‑EJ and K3‑VE engines specifies an opening temperature in the low‑to‑mid 80s Celsius, commonly around 82–88°C, with full opening reached in the 90s. Always match the replacement thermostat’s stamped rating to factory spec.

Should the thermostat be changed during a coolant service?
It’s not mandatory, but it’s often done preventatively if the history is unknown or there are symptoms like slow warm‑up or temperature swings. Given the low cost, pairing a new thermostat with fresh coolant can save headaches later.