Nissan Maxima 1993-1998 Repair Guide

Cooling System

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FLUID RECOMMENDATION



The cooling fluid, or antifreeze, should be changed every 30,000 miles or 24 months. When replacing the fluid, use a mixture of 50 percent distilled water and 50 percent ethylene glycol antifreeze. On 1993-1995 models, Nissan recommends a modified mixture of 70 percent water and 30 percent cooling fluid.

Check the freezing protection rating at least once a year, preferably just before the winter sets in. This can be done with an antifreeze tester (most service stations will have one on hand and will probably check it for you, if not, they are available at an auto parts store). Maintain a protection rating of at least -20°F (-29°C) to prevent serious engine damage as a result of freezing and to assure the proper engine operating temperature.

It is also a good idea to check the cooling system for leaks. A pressure test gauge is available to perform such a task. This is an excellent tool for locating small pinhole leaks and loose hose connections, which could lead to an overheated engine.

LEVEL CHECK



See Figures 1, 2, 3 and 4

Check the coolant level every 3000 miles or once a month. In hot weather operation, it may be a good idea to check the level once a week. Check for loose connections and signs of deterioration of the coolant hoses. Maintain the coolant level between the MAX and MIN marks on the coolant expansion (recovery) tank. If the coolant expansion tank is empty, check the coolant level in the radiator. if the level is below the filler neck, refill the radiator, then refill the expansion tank to the proper level with the appropriate mixture of coolant and water.



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Fig. Fig. 1: NEVER open the radiator cap when the engine is hot



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Fig. Fig. 2: The engine coolant level should always be maintained between the MIN and MAX markings on the expansion tank



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Fig. Fig. 3: When adding coolant, use of a funnel is advised to prevent any spillage onto the accessory drive belts, which will cause slippage



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Fig. Fig. 4: Add coolant to the radiator if the level is below the filler neck


CAUTION
Never remove the radiator cap when the vehicle is hot or overheated. Wait until it has cooled. Place a thick cloth over the radiator cap to shield yourself from the heat and turn the radiator cap, slightly, until the sound of escaping pressure can be heard. Do not turn any more; allow the pressure to release gradually. When no more pressure can be heard escaping, remove the cap with the heavy cloth, cautiously.

Never add cold water to an overheated engine while the engine is not running.

After filling the radiator, run the engine until it reaches normal operating temperature, to make sure the thermostat has opened and all the air is free from the system.

DRAIN & REFILL



See Figures 5, 6, 7, 8 and 9

To drain the cooling system, allow the engine to cool down before attempting to remove the radiator cap. Then turn the cap until it hisses. Wait until all pressure is off the cap before removing it completely.


CAUTION
To avoid burns and scalding, always handle a warm radiator cap with a heavy rag.

  1. If equipped with a manual air conditioning, set the heater TEMP control lever to the fully HOT position. If equipped with automatic air conditioning turn ignition switch ON and set temperature at MAXIMUM. Then turn the ignition switch OFF .
  2.  
  3. With the radiator cap removed, drain the radiator by loosening the petcock at the bottom of the radiator.
  4.  



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Fig. Fig. 5: Unscrew the petcock on the bottom of the radiator to drain the coolant



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Fig. Fig. 6: When draining the radiator, make sure the air bleed port plug and the radiator cap are removed to allow quick draining

  1. Remove the drain plugs from both sides of the engine block.
  2.  



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Fig. Fig. 7: Removing the engine block drain plugs will allow for a more thorough coolant change


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container.

  1. Close the petcock. Be careful not to damage the petcock when closing.
  2.  
  3. Install the drain plugs to both sides of the engine block.
  4.  



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Fig. Fig. 8: Always use thread sealer on the block drain plugs to prevent leaks

  1. Remove the air bleed port plug.
  2.  



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Fig. Fig. 9: The air bleed port plug should always be removed when adding coolant to a fully drained engine to prevent air pockets

  1. Refill the system with a 50/50 mix of ethylene glycol antifreeze; fill the system to 3 / 4 1 1 / 4 in. 1938mm) from the bottom of the filler neck on the radiator. Reinstall the radiator cap and the air bleed port drain plug.
  2.  
  3. Fill the coolant expansion tank to the MAX level.
  4.  
  5. Operate the engine at 2000 rpm for a few minutes and check the system for signs of leaks and for the correct level.
  6.  

FLUSHING & CLEANING THE SYSTEM



To flush the system you must first, drain the cooling system but do not close the petcock valve on the bottom of the radiator. You can insert a garden hose, in the filler neck, turn the water pressure on moderately then start the engine. After about 10 minutes or less the water coming out of the bottom of the radiator should be clear. Shut off the engine and water supply, allow the radiator to drain then refill and bleed the system as necessary.

Do not allow the engine to overheat. The supply of water going in the top must be equal in amount to the water draining from the bottom, this way the radiator will always be full when the engine us running.

Usually flushing the radiator using water is all that is necessary to maintain the proper condition in the cooling system.

Radiator flush is the only cleaning agent that can be used to clean the internal portion of the radiator. Radiator flush can be purchased at any auto supply store. Follow the directions on the label.

Also, there are a number of radiator flush "kits" available, that include a fitting to connect a garden hose into the engine cooling system. Once this fitting is installed, future radiator flushing is simplified by unscrewing a cap and fastening a garden hose. Use your own judgment with these kits, as they are not recommended by Nissan, and could possibly void the factory warranty.

 
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