Parts for your 1997 Daihatsu Gran move-Thermostat

1997 Daihatsu Gran Move Thermostat — what it does and when to swap it

Yes, the 1997 Daihatsu Gran Move absolutely uses a thermostat. This model (export name for the G301/G303 Pyzar) with the HD-E/HC family petrol engines is a conventional liquid‑cooled setup with a wax‑pellet thermostat located at the outlet housing on the cylinder head where the top radiator hose connects. This is documented in the Daihatsu Pyzar/Gran Move Workshop Manual (Cooling System section: Thermostat—Removal/Installation and Specifications), reflected in the Daihatsu Electronic Parts Catalogue listings for the thermostat and gasket for MY1997 Gran Move, and confirmed by major aftermarket catalogues from OEM-equivalent suppliers that list direct‑fit thermostats and seals for this vehicle.

The thermostat’s job is simple but crucial: it helps the engine warm up quickly and then holds it at a stable operating temperature (typically around an 82–88°C opening spec, stamped on the thermostat). By controlling coolant flow to the radiator, it keeps the motor running sweet, the heater working properly, and the fuel economy and emissions in check. If it sticks open, the Gran Move can take ages to warm up, run rich, and the heater feels lukewarm. If it sticks shut, it’ll overheat fast under load—never keep driving if the temp gauge heads north.

As part of routine servicing, there’s no strict time‑based replacement, but it’s smart to replace the thermostat proactively when tackling major cooling work—coolant change, radiator replacement—or during a timing‑belt/water‑pump service on HD‑series engines. Always use a quality stat and a fresh O‑ring/gasket. Under the bonnet, access is at the upper radiator hose outlet on the head