Parts for your 2000 Daihatsu Yrv-Thermostat

2000 Daihatsu YRV Thermostat: what it does and when to replace it

Yes, the 2000 Daihatsu YRV definitely runs a thermostat. Technical references such as the Daihatsu YRV (M2) Workshop Manual – Cooling System section and the Daihatsu Electronic Parts Catalogue list a wax‑pellet thermostat and gasket/O‑ring for the K3‑VE and K3‑VET engines. It’s housed where the upper radiator hose meets the engine’s water outlet on the cylinder head. Autodata service information for this model also covers coolant refill/bleed procedures that assume a functioning thermostat is fitted.

The thermostat’s job is simple but crucial: it regulates coolant flow so the engine warms up quickly, then holds a stable operating temperature (typically in the low‑to‑mid‑80s °C range as specified in the service data). That steadiness keeps fuel economy, emissions and heater performance on point, and it protects the engine—and turbo on K3‑VET—from thermal stress. Without a working thermostat, the YRV can run too cool or too hot, either of which can shorten engine life and send fuel use through the roof.

• Stuck open: long warm‑up, cool temp gauge on the move, weak cabin heat, higher fuel use
• Stuck closed: overheating, hard upper hose, coolant boiling, radiator fan running constantly
• Intermittent: fluctuating gauge, sudden temp spikes then drops
• Clues: radiator hose stays cold then suddenly goes hot as it opens, fault codes for low coolant temp may appear

As part of routine servicing, it’s smart to test or replace the thermostat when doing a coolant change, water pump work, or any overheating diagnosis—especially on higher‑kilometre cars. Use an OEM‑quality thermostat with the correct opening temperature and a new gasket/O‑ring. Fit it with the jiggle pin/bleed hole at the top, clean the housing faces, and tighten the housing bolts to the specified torque (around 10–12 N·m is typical—check the workshop manual for the exact spec). Refill with the correct long‑life coolant (the red/pink Toyota/Daihatsu‑type premix is commonly specified) and bleed air carefully. After a short drive, recheck the level, inspect for leaks at the housing, and confirm the temp gauge sits steady. If the fan cycles normally and the heater is toasty, the YRV’s cooling system is doing its job.

Popular questions about the 2000 Daihatsu YRV thermostat

Where is the thermostat on a 2000 Daihatsu YRV?
It lives in the water outlet housing at the engine end of the upper radiator hose. Two bolts secure the housing, the thermostat sits behind it with an O‑ring or paper gasket. Always refit with the bleed pin at 12 o’clock and a fresh seal.

What opening temperature should be used?
Daihatsu specifies a thermostat in the low‑to‑mid‑80s °C range for the K3 engines. Check the service manual or parts listing for the exact rating for your engine code and climate. Don’t mix and match random temps—use the specified value.

Can the YRV be driven without a thermostat?
It shouldn’t be. Running without one can cause chronic over‑cooling, poor economy, higher wear, and paradoxically can trigger overheating because coolant may circulate too quickly to shed heat properly. The thermostat is essential for stable, reliable operation.