Parts for your 2018 Nissan Serena-Thermostat housing

2018 Nissan Serena Thermostat Housing: What It Does and How to Look After It

Yes, the 2018 Nissan Serena uses a thermostat housing. Technical sources, including the Nissan C27 Serena Electronic Service Manual (ESM) — Cooling System (CO) and Engine Mechanical (EM) sections — and Nissan FAST genuine parts catalogues, list a “water outlet/thermostat housing” and matching thermostat for both the MR20DD petrol engine and the e-POWER variant’s HR12 engine. So, it’s a relevant service item on this model.

On the Serena, the thermostat housing anchors the thermostat, routes coolant from the engine to the radiator, and provides ports for sensors and bypass flow. Its job is to help the engine warm up quickly, then hold a steady operating temperature so the Serena runs efficiently, keeps the heater toasty, and avoids overheating under the Kiwi or Aussie sun.

In normal servicing, the housing itself isn’t a scheduled replacement item, but it should be inspected whenever coolant is changed or if there are temperature irregularities. Plastic housings can warp over time, O-rings flatten, and flanges can seep — particularly if coolant has been neglected. Nissan’s long-life blue coolant should be used, and mixing types should be avoided.

• Common symptoms to watch for:
  • Coolant weeping around the housing seam or hose necks
  • Overheating, slow warm-up, or erratic gauge behaviour (stuck thermostat)
  • Heater going cold at idle, return when revved (air in system or leak)
  • Crusty dried coolant traces near the housing or under the bonnet

Replacement tips for the Serena’s thermostat housing and thermostat:

1. Replace the thermostat and O-ring/gasket as a set, consider the housing if it’s warped, cracked, or the hose spigots are chalky.
2. Clean mating faces gently and torque the housing bolts evenly to spec (light fasteners — don’t overdo it).
3. Refill with Nissan-approved blue long-life coolant, ideally using a vacuum fill. If not, bleed carefully with the heater on HOT to purge air.
4. After a road test, recheck the level and inspect for weeps.

There’s no fixed interval for the housing itself, but many techs in AU/NZ will pre-emptively fit a new thermostat (and O-ring) around 150,000–200,000 km or when doing major cooling work. If the Serena’s used for towing or lots of urban stop‑start, more frequent inspections are smart. A tidy cooling system keeps the MR20DD or HR12 running sweet, protects the CVT from heat soak, and saves headaches down the track.

Popular questions about the 2018 Nissan Serena thermostat housing

Does the 2018 Serena have a thermostat housing and where is it?

Yes. It’s integrated at the engine’s water outlet where the main radiator hose connects — front or side of the engine bay depending on engine orientation. On e-POWER models, it’s on the generator engine assembly.

How often should the thermostat or housing be replaced?

There’s no strict interval. Replace the thermostat and O-ring if there are temperature issues, leaks, or during major cooling service. The housing is replaced if cracked, warped, or corroded. Many owners opt to refresh these around 150,000–200,000 km.

What coolant should be used after thermostat housing work?

Use Nissan-approved blue long-life coolant (premix or mixed as directed). Don’t mix coolant types. After refilling, bleed the system properly to avoid air pockets and erratic temps.