Parts for your 2012 Nissan Pathfinder-Radiator cap

2012 Nissan Pathfinder radiator cap — what it does and how to look after it

Based on the 2012 Nissan Pathfinder (R51) Factory Service Manual (Cooling System, CO) and the Nissan Electronic Parts Catalogue for the R51, this model uses a pressurised radiator with a dedicated pressure cap mounted on the radiator neck, and a separate, non‑pressurised coolant reservoir. The FSM specifies testing the cap’s opening pressure and sealing condition, and parts listings show a rated cap for both V6 petrol and diesel variants. So yes — a radiator cap is absolutely relevant on a 2012 Pathfinder.

The radiator cap isn’t just a lid, it’s a precision pressure valve. It lets the cooling system run at a set pressure (typically around 0.9 bar/13 psi), which lifts the coolant’s boiling point and keeps the engine happy on hot days, towing, or long climbs. When pressure rises, the cap allows excess coolant to flow to the reservoir. As the engine cools, the cap’s vacuum valve draws coolant back in, preventing air pockets and hose collapse. A tired cap can trigger sneaky issues like gradual coolant loss, overheating at highway speeds, or a radiator hose that flattens under the bonnet after shutdown.

For Aussie and Kiwi conditions, it pays to check the cap at every service. Look for cracked rubber, crusty deposits, a sticky spring, or a damaged sealing seat on the radiator neck. If the cap doesn’t hold pressure on a tester, bin it. Stick with the specified pressure rating — going higher can stress the radiator and hoses, lower can invite boil‑over.

• Replace the cap whenever the cooling system is renewed, after an overheat, or roughly every 5 years/100,000 km if condition is unknown.
• Only open the cap stone‑cold. Twist to the first notch to vent any residual pressure, then remove.
• Inspect the filler neck for nicks or corrosion that could compromise sealing.
• Refit the new cap firmly, then top the radiator and set the reservoir to the “FULL COLD” mark.

After replacement, run the engine with the heater on hot to purge air, squeeze the upper hose to burp bubbles, and recheck levels once it cools. Use a quality ethylene glycol coolant compatible with Nissan specs (often premixed), and keep an eye on the reservoir between services. A healthy cap is cheap insurance for the Pathfinder’s cooling system, especially if it tows, tours, or sees plenty of kilometres.

Popular questions about 2012 Nissan Pathfinder radiator caps

What pressure radiator cap does a 2012 Pathfinder use?
Most R51 Pathfinders use a cap rated around 0.9 bar (13 psi). Always match the rating on the original cap or the vehicle label and use a high‑quality equivalent or genuine part. Avoid “up‑rating” the pressure unless a Nissan bulletin specifically calls for it.

How often should the radiator cap be replaced?
Have it inspected at every service. Replace it if it fails a pressure test, after any overheating event, when renewing the cooling system, or roughly every 5 years/100,000 km if its history is uncertain. It’s an inexpensive part that protects far pricier components.

Where is the radiator cap, and is the overflow bottle pressurised?
The pressure cap sits on the radiator neck under the bonnet. The coolant reservoir (overflow bottle) uses a simple non‑pressurised cap. Only the radiator cap manages system pressure and vacuum recovery on the 2012 Pathfinder.