Parts for your 2013 Nissan Serena-Thermostat housing

2013 Nissan Serena Thermostat Housing — What It Does and When to Service It

Referencing technical sources, the 2013 Nissan Serena (C26 series, including S-HYBRID) does use a thermostat housed within a dedicated water inlet/water outlet assembly, commonly called the thermostat housing. This is detailed in the Nissan Serena C26 Service Manual (Cooling System section), reflected in Nissan’s FAST electronic parts catalogue for C26 MR20-series engines, and supported by major aftermarket catalogues that list a thermostat/housing assembly for the model. So yes, a thermostat housing is fitted and relevant on this vehicle.

On the Serena, the thermostat housing secures the thermostat, seals the coolant path with an O-ring or gasket, and directs coolant between the engine, radiator and bypass circuit to keep the engine in its sweet spot. It helps the engine warm up quickly, then holds temperature steady under load and in traffic, protecting against overheating and overcooling. On some variants it can also serve as a mounting point for sensors and the lower radiator hose, making it a key junction in the cooling system.

With age, the plastic housing can warp or crack, and the seals harden. That’s when small leaks, damp patches, or a faint coolant smell might show up under the bonnet. A sticking thermostat can trigger slow warm-up, fluctuating temperature, weak cabin heat, or a check engine light (often P0128 for low coolant temperature). Left alone, those issues can bump fuel use and stress the engine.

As part of servicing, it’s smart to inspect the housing for staining, crusty residue, or coolant at the seams. There’s no fixed replacement kilometre for the thermostat on the Serena, but many workshops recommend assessing it around major cooling system work or at roughly 100,000 km, and replacing the housing if it’s brittle or weeping. When replacing, use a quality thermostat and fresh O-ring/gasket, follow the factory torque specs, and refill with the correct Nissan blue long-life coolant (50/50 mix). Bleed the system properly—set the heater to hot, use the bleed point where provided, idle until the fans cycle, and top up the overflow bottle after a couple of heat cycles. After the job, confirm the heater blows hot, the gauge sits steady, and there are no damp spots around the housing. Sticking with OEM or equivalent parts and proper bleeding makes a big difference to reliability on the Serena’s MR20-series engine.

Popular questions

Where is the thermostat housing on a 2013 Nissan Serena?
It’s mounted on the engine at the end of the lower radiator hose—often referred to as the water inlet. On the C26 Serena with MR20-series engines, it faces the gearbox side of the bay. Access is typically easier from the front or the right-hand wheel-arch area with the splash shield removed. Always confirm exact placement against a workshop manual for the specific trim and engine code.

What coolant should be used after replacing the housing, and how is it bled?
Use Nissan Genuine Blue long-life coolant (or an equivalent silicate-free, long-life premix) at 50/50. After fitting the new housing and thermostat, fill the system, open the bleed screw if fitted, set the heater to hot, and idle the engine until the fans cycle. Top up the radiator and overflow as needed, then recheck levels after a couple of heat cycles. Proper bleeding prevents airlocks and unstable temperatures.

How can someone tell if the thermostat or housing is failing?
Common signs include slow warm-up, temperature swings, poor cabin heat, a coolant smell, or dampness near the housing seam. A check engine light with code P0128 is another hint that the thermostat is stuck open. Any visible leak or staining around the housing means it’s time to investigate and likely replace the seal or the assembly.