Parts for your 2016 Nissan Serena-Radiator cap

2016 Nissan Serena radiator cap

Yes, the 2016 Nissan Serena is fitted with a pressure-type radiator cap (on the radiator neck or on a pressurised expansion tank, depending on market and engine variant). This is confirmed by Nissan service literature and parts catalogues that specify a cap assembly for the Serena platform and include inspection procedures for the cap’s pressure-holding function.

• Nissan Serena C26/C27 Service Manual (Cooling System/CO): includes “Radiator Cap” inspection and pressure specifications.
• Nissan FAST parts catalogue, Group 21: lists 21430 (Cap Assy – Radiator) for Serena applications.
• AU/NZ aftermarket catalogues (e.g., radiator cap listings) specify a 0.9 bar/approx. 88–108 kPa cap for 2011–2016 Serena variants.

The radiator cap on a 2016 Nissan Serena does more than just seal the filler neck. It’s a pressure regulator that lets the cooling system run at a set pressure, lifting the coolant’s boiling point so the Serena can handle hot summer days and long uphill runs without boiling over. Inside the cap are spring-loaded valves: one controls pressure release to the overflow/expansion bottle as coolant expands, and another allows coolant to be drawn back as the engine cools, keeping the system full and free of air.

For owners and workshops, treating the cap as a service item is smart preventative maintenance. Check it at every service—always stone cold—with a visual once-over for hard, cracked or swollen rubber seals, bent tabs, corrosion on the seat, or coolant crust on the neck. If the spring feels weak or the seal looks tired, swap it. On many Serena variants the correct rating is around 0.9 bar, always match the pressure number stamped on the old cap or confirmed in the service info. A cap that’s too high can stress hoses and the radiator, too low can cause early boil-over and air ingress.

Classic symptoms of a dodgy cap include random temperature spikes in traffic, a collapsed upper hose after cool-down, coolant loss without obvious leaks, or the heater blowing cool at idle then hot on the move. Because the cap is cheap and critical, replacing it every 3–5 years is good insurance. When fitting, clean the filler neck, seat the cap squarely, and lock it fully. If the system’s been open, bleed any air per the Serena procedure and top up with the correct Nissan long-life coolant mix. Never open the cap hot—wrap a rag around it and crack it slowly only when the system is cold to avoid scalding.

Whether mounted on the radiator or a pressurised reservoir, a healthy cap keeps the Serena’s cooling system stable, leak-free and performing as it should.

Where is the radiator cap on a 2016 Nissan Serena?

Depending on the market spec, it’s either on the radiator’s top tank or on a pressurised expansion bottle near the left-hand side of the bay. If the radiator has no filler neck, the cap you see on the reservoir is the pressure cap.

What pressure rating cap does it use?

Most Serena variants of this era use a cap around 0.9 bar (about 88–108 kPa). Always confirm by reading the number stamped on the existing cap or checking the service information for the exact engine/variant.

Is it safe to drive with a faulty radiator cap?

Not recommended. A failing cap can cause coolant loss, overheating, and air pockets that stress the engine. If the cap is suspect, replace it and recheck coolant level and bleeding before driving any distance.