Nissan Pick-ups and Pathfinder 1989-1995

Cooling System



When additional coolant is required to maintain the proper level, always add a mixture of aluminum-compatible antifreeze/coolant and water. Typically, a 50/50 mixture of antifreeze and water is recommended (even for vehicles which are not exposed to cold winter temperatures), since this mixture also imparts the necessary corrosion inhibition. A greater concentration of antifreeze may be used, but the coolant mixture's level of protection actually lessens if too much antifreeze is used. Unless you are simply topping off the cooling system, straight antifreeze should never be added without some water. For additional information on determining the optimum concentration for your vehicle, refer to the antifreeze manufacturer's labeling.

Although Nissan recommends ethylene glycol-based antifreeze (which has long been the prevalent type on the market), other types (such as propylene glycol) may also be suitable for use in your vehicle. Be sure to thoroughly read the alternative product's labeling to ensure compatibility before switching to a different formula.


See Figures 1 through 5

Dealing with the cooling system can be a tricky matter unless the proper precautions are observed. It is best to check the coolant level in the radiator when the engine is cold. This is done by checking the expansion tank. If coolant is visible above the MIN mark on the tank, the level is satisfactory. Always be certain that the filler caps on both the radiator and the reservoir are tightly closed.

In the event that the coolant level must be checked when the engine is warm or on engines without an expansion tank, place a thick rag over the radiator cap, then slowly turn the cap counterclockwise until it reaches the first detent. Allow all the hot steam to escape. This will allow the pressure in the system to drop gradually, preventing an explosion of hot coolant. When the hissing noise stops, remove the cap the rest of the way.

It's a good idea to check the coolant every time that you stop for fuel. If the coolant level is low, add equal amounts of suitable antifreeze and clean water. Fill the expansion tank to the MAX level. On models without an expansion tank, add coolant through the radiator filler neck.

Never add cold coolant to a hot engine unless the engine is running, to avoid cracking the engine block.

Avoid using water that is known to have a high alkaline content or is very hard, except in emergency situations. Drain and flush the cooling system as soon as possible after using such water.

The radiator hoses and clamps and the radiator cap should be checked at the same time as the coolant level. Hoses which are brittle, cracked, or swollen should be replaced. Clamps should be checked for tightness (screwdriver-tight only)! Do not allow the clamp to cut into the hose or crush the fitting. The radiator cap gasket should be checked for any tears, cracks, swelling, or any signs of incorrect seating in the radiator neck.

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Fig. Fig. 1: View of the radiator cap installed-never open when the engine is hot!

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Fig. Fig. 2: Add engine coolant to the radiator with a funnel to avoid spills

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Fig. Fig. 3: View of the coolant expansion tank

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Fig. Fig. 4: Remove the cap on the coolant expansion tank and add coolant to the proper level

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Fig. Fig. 5: Add engine coolant to the expansion tank with a funnel to avoid spills


See Figures 6 through 12

When draining the coolant, keep in mind that cats and dogs are attracted by 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. Coolant should be reused unless it is contaminated or several years old.

Complete draining and refilling of the cooling system at least once every two years will remove accumulated rust, scale and other deposits.

Use a good quality antifreeze with water pump lubricants, rust inhibitors and other corrosion inhibitors along with acid neutralizers. Use a permanent-type coolant that meets specification ESE M97B44A or the equivalent.

  1. Drain the existing coolant as follows: Position suitable drain pans beneath the radiator and engine block. Open the radiator petcock and engine drain plug(s)-2 on the V6 engine; 1 on the 4-cylinder engine-or disconnect the bottom radiator hose at the radiator outlet.

If it is rusted or difficult to open, spray the radiator petcock with some penetrating lubricant.

  1. Set the heater temperature controls to the full HOT position.
  3. Close the petcock and tighten the drain plug(s) to 25-33 ft. lbs. (34-44 Nm), or reconnect the lower hose. Open the air relief plug (except on the Z24i engine), then fill the system with water.
  5. Add a can of quality radiator flush. Be sure the flush is safe to use in engines having aluminum components.
  7. Idle the engine until the upper radiator hose gets hot. Race it 2 or 3 times, then shut it OFF . Let the engine cool down.
  9. Drain the system again.

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Fig. Fig. 6: Coolant drain plug location-VG30i engine

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Fig. Fig. 7: Coolant drain plug location-KA24E engine

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Fig. Fig. 8: Left-side coolant drain plug location-VG30E engine

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Fig. Fig. 9: Right-side coolant drain plug location-VG30E engine

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Fig. Fig. 10: Release the air in the cooling system here-VG30i engine

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Fig. Fig. 11: Release the air in the cooling system here-KA24E engine

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Fig. Fig. 12: Release the air in the cooling system here-VG30E engine

  1. Repeat this process until the drained water is clear and free of scale.
  3. Close the petcock and drain plug(s) or, if applicable, connect the radiator hose.
  5. If equipped with a coolant recovery system, flush the reservoir with water and leave empty.

Always open the air relief plug before filling the cooling system, in order to bleed the trapped air. Only when the cooling system is bled properly can the correct amount of coolant be added to the system.

  1. Determine the capacity of your cooling system (see the Capacities Chart, later in this section). Add the appropriate ratio of quality aluminum-compatible antifreeze and water (normally a 50/50 mix) to provide the desired protection. With the air relief plug open, add the coolant mixture through the radiator filler neck until full, then close the bleeder plug and radiator cap.
  3. Using the same concentration of clean antifreeze and water, fill the expansion tank to the MAX line, then cap the tank.


Most permanent antifreeze/coolants have a colored dye added which makes the solution an excellent leak detector. When servicing the cooling system, check for leakage at:

All hoses and hose connections
Radiator seams, radiator core, and radiator draincock
All engine block and cylinder head freeze (core) plugs, and drain plugs
Edges of all cooling system gaskets (head gaskets, thermostat gasket)
Transmission fluid cooler
Heating system components
Water pump

In addition, check the engine oil dipstick for signs of coolant in the oil; also, check the coolant in the radiator for signs of oil. Investigate and correct any indication of coolant leakage.

Check the Radiator Cap

See Figure 13

While you are checking the coolant level, check the radiator cap for a worn or cracked gasket. If the cap doesn't seal properly, fluid will be lost and the engine will overheat. A worn cap should be replaced with a new one.

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Fig. Fig. 13: Check the radiator cap seal and gasket condition

Clean Radiator of Debris

See Figure 14

Periodically clean any debris such as leaves, paper, insects, etc, from the radiator fins. Pick the large pieces off by hand. The smaller pieces can be washed away with water pressure from a hose.

Carefully straighten any bent radiator fins with a pair of needlenose pliers. Be careful, the fins are very soft. Don't wiggle the fins back and forth too much. Straighten them once and try not to move them again.

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Fig. Fig. 14: Clean the radiator fins of any debris which impedes air flow


See Figure 15

A 50/50 mix of antifreeze/coolant concentrate and water will usually provide the necessary protection. Freeze protection may be checked by using a cooling system hydrometer. Inexpensive hydrometers (floating ball types) may be obtained from a local department store (automotive section) or an auto supply store. Follow the directions packaged with the coolant hydrometer when checking protection.

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Fig. Fig. 15: The freezing protection rating can be checked with an antifreeze tester