Parts for your 2020 Toyota Hilux-Thermostat

2020 Toyota HiLux thermostat — what it does and when to service it

Technical sources confirm the 2020 Toyota HiLux is fitted with a conventional engine coolant thermostat. The Toyota Repair Manual for HiLux AN120/AN130 (Cooling System – Thermostat section) details removal and installation, and the Toyota Electronic Parts Catalogue lists “Thermostat, Water” for the 1GD‑FTV 2.8L and 2GD‑FTV 2.4L diesels (and applicable petrol variants), with an opening temperature around the low‑80s °C. Major aftermarket catalogues for Australia and New Zealand (e.g., Tridon, Dayco, Gates) also list direct‑fit thermostats for the 2020 HiLux. So the thermostat is absolutely relevant on this model.

The thermostat’s job is to help the engine warm up quickly, then hold it at a stable operating temperature. On a HiLux, that means better fuel economy, proper heater performance, and consistent emissions control. For the diesels, the cooling system reaching and holding spec temp also supports DPF strategy. The ECU assumes the thermostat is doing its thing, if not, driveability and efficiency can suffer.

It’s not a scheduled replacement item, but it should be checked whenever the cooling system is serviced or coolant is replaced (Toyota Super Long Life Coolant). Replace it if there are symptoms such as:

• Slow warm‑up or the temp gauge never reaching normal
• Overheating under load or at idle
• Fluctuating temperature or weak cabin heat
• Cooling fans running excessively
• Diagnostic trouble codes like P0128 (coolant temperature below thermostat regulating temperature)

Good practice is to use a genuine thermostat (or a quality equivalent) with the correct opening temperature for the engine, and a new O‑ring/gasket. On the HiLux, the thermostat sits in the water inlet/thermostat housing—trace the lower radiator hose to find it. Typical replacement workflow:

1. Work stone cold, safely drain coolant.
2. Remove intake/ancillary bits as needed for access.
3. Unbolt the housing, note the jiggle‑valve orientation (usually near 12 o’clock), and remove the thermostat.
4. Clean mating surfaces, install the new unit and seal, orient correctly, and torque bolts to spec (see the Toyota repair manual).
5. Refill with premixed Toyota SLLC, bleed air with the heater set to hot, check for leaks, and verify stable operating temperature with a scan tool or gauge.

If the cooling system is being renewed at high kilometres, many workshops will proactively fit a new thermostat to avoid repeat labour later. Always match the part to the VIN as Toyota supersedes part numbers over time.

Where is the thermostat on a 2020 HiLux?

Follow the lower radiator hose to the engine—where it meets the alloy housing is where the thermostat sits. It’s held in by a small housing with a few bolts. Access can vary by engine (1GD/2GD), so expect to shuffle an intake duct or two for room.

What temperature should it run at?

The thermostat typically begins opening in the low‑80s °C. In normal driving, coolant temperature reported via a scan tool will usually live in the mid‑80s to low‑90s °C once warmed up, and the dash gauge will sit steady in the middle.

Is it electronically controlled?

No—on the 2020 HiLux it’s a wax‑pellet, spring‑loaded thermostat. The ECU monitors coolant temperature via a sensor and can flag a fault if the thermostat is stuck open or closed, but the thermostat itself isn’t electrically actuated.