Parts for your 2016 Toyota Bb-Thermostat

2016 Toyota bB Thermostat — What It Does and When to Service It

Based on technical sources, the 2016 Toyota bB is fitted with a conventional engine coolant thermostat and it’s very much relevant to servicing. Toyota’s Electronic Parts Catalogue for the QNC20/QNC21 bB lists a replaceable thermostat in the cooling system assembly, and Toyota’s TIS repair procedures for the 1NZ-FE and 2SZ-FE engines include thermostat inspection and replacement steps. Major aftermarket catalogues (Aisin, Gates, etc.) also specify a direct-fit thermostat for this model and year.

On the 2016 Toyota bB, the thermostat is a small, wax‑pellet valve that manages coolant flow to keep the engine right in its sweet spot. It stays closed while the engine warms up, helping it reach operating temperature quickly for better fuel economy, smoother running and faster cabin heat. Once the coolant reaches its set point (typically in the low‑to‑mid 80s °C), the thermostat opens and meters flow to the radiator so the engine doesn’t overheat under load or in hot Aussie and Kiwi summers.

Owners will usually only think about the thermostat when it misbehaves. If it sticks open, the bB can take ages to warm up, the heater might be weak, and fuel use can creep up. If it sticks closed, overheating under the bonnet can happen fast. There isn’t a strict time-based replacement interval from Toyota, but it’s smart preventative maintenance to assess the thermostat around 100,000–150,000 kilometres or 7–10 years, or whenever the cooling system is being serviced (coolant change, water pump or radiator work).

Good practice on a 2016 bB includes using a quality OEM‑spec thermostat and a fresh gasket or O‑ring, orienting the jiggle pin at 12 o’clock, torquing the housing bolts correctly, and bleeding air from the system. Refill with Toyota Super Long Life Coolant (pink, premixed) and check for leaks and stable temperatures on a scan tool. On the 1NZ‑FE, the thermostat sits in the water inlet housing near the lower radiator hose, access is straightforward with basic sockets and a catch pan.

• Tell‑tale faults: slow warm‑up, low temp gauge, weak heater, or rising temps in traffic.
• Handy extras while you’re there: inspect hoses, clamps and the radiator cap, replace if perished.
• Labour time is typically about an hour, it’s an easy add‑on during a coolant service.

Done right, a fresh thermostat keeps the bB running sweet as under all conditions, from frosty mornings to summer road trips.

Popular questions about the 2016 Toyota bB thermostat

Where is the thermostat on a 2016 Toyota bB?
It’s housed in the water inlet at the engine block side, where the lower radiator hose connects. Remove the hose and two or three bolts on the housing to access the thermostat and its gasket. Expect a bit of coolant spillage, so have a tray ready.

What temperature does the bB’s thermostat open?
Most 2016 bB units open in the low‑to‑mid 80s °C range. The spec is stamped on the thermostat. You can verify operation with a scan tool (watch coolant temp) and by feeling the upper hose warm quickly as the valve opens.

How much does replacement cost in AU/NZ?
Parts typically run about AUD/NZD $40–$100 for an OEM‑quality thermostat and seal. With 0.8–1.2 hours of labour, total fitted cost commonly lands around AUD/NZD $180–$350 depending on workshop rates and any extra cooling system items replaced.