Checking Radiator Cap

WARNING: This page is about a different car, the 2019 Nissan NV3500 HD, 2019 Nissan NV2500 HD, and 2019 Nissan NV1500. However, it is still accessible from the selected car via links, so may be relevant.

WARNING:

Do not remove the radiator cap or reservoir tank cap when the engine is hot. Serious burns could occur from high-pressure engine coolant escaping from the cooling system.
When removing the radiator cap or reservoir tank cap, wrap a thick cloth around the cap and slowly turn it a quarter turn to allow built-up pressure to escape. Then carefully remove the cap by turning it all the way.

Check the pressure valve of the radiator cap.

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- Replace the radiator cap if the metal plunger (B) on the pressure valve cannot be seen around the edge of the rubber gasket (A).
- Replace the radiator cap if there is damage or deposits of foreign material on the rubber gasket or pressure valve.
  CAUTION: Thoroughly wipe out the radiator filler neck to remove any waxy residue or foreign material.
Check the negative-pressure valve of the radiator cap.

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- Replace the radiator cap if the negative-pressure valve does not close completely when pulled open and released.
- Replace the radiator cap if there is damage or deposits of foreign material on the valve seat of the negative-pressure valve.
- Replace the radiator cap if there is an abnormality in the operation of the negative-pressure valve.

Check radiator cap relief pressure.

Check the radiator cap relief pressure using Tools (A) and (B), and suitable tool (C).

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Tool number (A)	:--(J-51771-5)
Tool number (B)	:--(J-51771-9)
Tool number (C) (commercially available)	:--(J-33984-A or equivalent)
Radiator cap relief pressure	: Refer to Standard and Limit .

When connecting the radiator cap to suitable tool (C), apply water or coolant to the radiator cap seal surface.
Replace the radiator cap if the radiator cap relief pressure is outside of specification.

Inspect the radiator cap.

CAUTION: Thoroughly wipe out the radiator filler neck to remove any waxy residue or foreign material.

Replace the radiator cap if deposits of waxy residue or other foreign materials are on the black rubber gasket or the metal retainer.