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How to Check for Cooling System Leaks in a Nissan Altima

by Contributor

To keep your Nissan Altima in good operating condition, performing regular checks for cooling system leaks is necessary. Any signs of a drop in coolant level can also signal a possible leak. Finding leaks early can save your Altima from overheating and the potential engine damage that comes with it. Examining a cooling system doesn't require extensive knowledge of auto mechanics.

Step 1

Relocate your Nissan Altima from its usual parking spot and inspect the area underneath for any signs of leakage. Radiator coolant is bright in color, usually green, orange, red or other bright color, making it easy to spot. However, even if there isn't any coolant present, you still may have a cooling system leak, as the heat from the engine can vaporize the coolant prior to it reaching the ground.

Step 2

Open the hood, grab a flashlight and check the entire radiator for leakage. Look underneath the radiator, as it can sustain damage from rock and road debris during normal operation. Inspect the radiator for any discoloration and corrosion, as this is a likely sign of a leak.

Step 3

Inspect the hoses that connect the radiator to the engine and the engine to the heater core. Check for any bulging, cracking and splitting on the hoses. Look for fresh coolant, corrosion or discoloration around these areas.

Step 4

Test the connection clamps that connect the hoses to the cooling system. These connections can loosen due to engine vibration and also cause leaks.

Step 5

Check the Nissan Altima's water pump and the gasket seal for possible leaks. The pump is behind the engine fan and the gasket seal secures the connection between the water pump and engine block. Examine these auto parts for fresh leaks, discoloration or corrosion.

Step 6

Remove the radiator cap and add fresh coolant. Touch the radiator to verify the external temperature before you attempt to remove the radiator cap. Turn the radiator cap one revolution to relieve any internal pressure, step away, wait a minute and then take the radiator cap off completely.

Turn on the engine of the Nissan Altima with the heater set to high. Let it run for about 15 minutes. Shut off the engine and check the hoses, water pump, gasket seal and radiator for leaks one more time. If you still can't find the leak it's probably an internal one and you should consult with a cooling system specialist for further diagnostics.


  • Whenever you work with coolant, wear gloves and a long-sleeved shirt to protect your skin.


  • Be extremely careful when working with coolant, as it's very toxic to people and pets.

Items you will need

  • Flashlight
  • Coolant
  • Gloves
  • Long-sleeved shirt

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