ISUZU Amigo/Pick-ups/Rodeo/Trooper 1981-1996

Cooling System

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See Figures 1 and 2


CAUTION
Never remove the radiator cap under any conditions while the engine is hot! Failure to follow these instructions could result in damage to the cooling system, engine and/or personal injury. To avoid having scalding hot coolant or steam blow out of the radiator, use extreme care whenever you are removing the radiator cap. Wait until the engine has cooled, then wrap a thick cloth around the radiator cap and turn it slowly to the first stop. Step back while the pressure is released from the cooling system. When you are sure the pressure has been released, press down on the radiator cap (with the cloth still in position), turn and remove the radiator cap.

Dealing with the cooling system can be a dangerous matter unless the proper precautions are observed. It is best to check the coolant level in the radiator when the engine is cold. All vehicles covered by this guide should be equipped with a coolant recovery tank. If the coolant level is at or near the MIN line (engine cold) or the MAX line (engine hot), the level is satisfactory. Always be certain that the filler caps on both the radiator and the recovery tank are closed tightly.

In the event that the coolant level must be checked when the engine is hot and the vehicle is not equipped with a coolant recovery tank, place a thick rag over the radiator cap and slowly turn the cap counterclockwise until it reaches the first detent. Allow all 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, carefully remove the cap the rest of the way.

If the coolant level is found to be low, add a 50/50 mixture of ethylene glycol-based, or ther suitable, antifreeze and clean water. If not equipped with a recovery tank, coolant must be added through the radiator filler neck. On most models, which are equipped with a recovery tank, coolant may be added either through the filler neck on the radiator or directly into the recovery tank.


CAUTION
Never add coolant to a hot engine unless it is running. If it is not running, you run the risk of cracking the engine block.

It is wise to pressure check the cooling system at least once per year. If the coolant level is chronically low or rusty, the system should be thoroughly checked for leaks.



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Fig. Fig. 1: Cutaway view of a typical cooling system flow



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Fig. Fig. 2: Cooling systems should be pressure tested for leaks periodically

At least once every 2 years or 30,000 miles (48,000 km), the engine cooling system should be inspected, flushed and refilled with fresh coolant. If the coolant is left in the system too long, it loses its ability to prevent rust and corrosion. If the coolant has too much water, it won't protect against freezing.

The pressure cap should be examined for signs of age or deterioration. Fan belt and other drive belts should be inspected and adjusted to the proper tension.

Hose clamps should be tightened, and soft or cracked hoses replaced. Damp spots, or accumulations of rust or dye near hoses, water pump or other areas, indicate possible leakage, which must be corrected before filling the system with fresh coolant.

FLUID RECOMMENDATIONS



Whenever adding or changing fluid, use a good quality of ethylene glycol, or other suitable, antifreeze (one that will not affect aluminum), mix it with water until a 50/50 antifreeze solution is attained.

LEVEL CHECK



On most late model vehicles, the fluid level may be checked by observing the fluid level marks of the recovery tank (see-through plastic bottle). The level should be near the MIN mark, as applicable, when the system is cold. At normal operating temperatures, the level should be at the MAX mark or between the MIN and the MAX marks. Only add coolant to the recovery tank as necessary to bring the system up to a proper level.


CAUTION
Should it be necessary to remove the radiator cap, make sure that the system has had time to cool, reducing the internal pressure.

On any vehicle that is not equipped with a coolant recovery or overflow tank, the level must be checked by removing the radiator cap. This should only be done when the cooling system has had time to sufficiently cool after the engine has been run. The coolant level should be within 1 / 2 in. (13mm) of the base of the radiator filler neck. If necessary, coolant can then be added directly to the radiator.

DRAIN AND REFILL



See Figures 3, 4, 5, 6, 7, 8 and 9


CAUTION
To avoid injuries from scalding fluid and steam, DO NOT remove the radiator cap while the engine and radiator are still HOT.

  1. Make sure the engine is cool and the vehicle is parked on a level surface, then remove the radiator neck cap and, if equipped, the recovery tank cap in order to relieve system pressure.
  2.  
  3. Position a large drain pan under the vehicle, then drain the existing antifreeze (coolant) by opening the radiator petcock and, if necessary, by removing the engine block drain plug(s). It its also possible to drain the system by disconnecting the lower radiator hose from the bottom radiator outlet.
  4.  


CAUTION
When draining 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 at which point it should be returned to a coolant recycling or hazardous waste disposal sight. Check your local laws for proper disposal methods.

  1. Close the radiator/engine drains or reconnect the lower hose.
  2.  



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Fig. Fig. 3: Be sure the rubber gasket on the radiator cap has a tight seal

  1. If necessary, empty the coolant reservoir and flush it. This is most easily done by removing the reservoir tank from the vehicle.
  2.  
  3. Determine the capacity of your coolant system (see capacities specifications). Through the radiator filler neck, add a 50/50 mix of quality antifreeze (ethylene glycol or other suitable formulation) and water to provide the desired protection.
  4.  
  5. Leave the radiator pressure cap off, then start and run the engine until the thermostat heats up and opens; this will allow air to bleed from the system and provide room for additional coolant to be added to the radiator.
  6.  
  7. Add additional coolant to the radiator, as necessary, until the level is within 1 / 2 in. (13mm) of the radiator's filler neck base.
  8.  



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Fig. Fig. 4: Before draining the coolant, heed any warnings or cautions regarding the cooling system



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Fig. Fig. 5: To drain the coolant, first remove the radiator cap, then ...



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Fig. Fig. 6: ... remove the drain plug from the radiator and drain the coolant into a catch pan



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Fig. Fig. 7: Install the drain plug, then fill the radiator with the proper mixture of antifreeze and water



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Fig. Fig. 8: Once the radiator and engine are full, top of the coolant reservoir-Trooper shown



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Fig. Fig. 9: The coolant reservoir on this Rodeo is more towards the back of the engine compartment

  1. Stop the engine and check the coolant level.
  2.  
  3. Check the level of protection with an antifreeze tester, then install the radiator pressure cap.
  4.  
  5. If equipped with a coolant recovery/overflow tank, add coolant to the tank, as necessary, to achieve the proper level.
  6.  
  7. Start and run the engine to normal operating temperature, then check the system for leaks.
  8.  

FLUSHING AND CLEANING THE SYSTEM



See Figure 10

The cooling system should be drained, thoroughly flushed and refilled at least every 30,000 miles (48,000 km) or 24 months. These operations should be done with the engine cold, especially if a backpressure flushing kit is being used. Completely draining, flushing and refilling the cooling system at least every two years will remove accumulated rust, scale and other deposits. Coolant in late model vehicles is typically a 50/50 mixture of ethylene glycol and water for year round use. Use a good quality antifreeze with water pump lubricants, rust inhibitors and other corrosion inhibitors along with acid neutralizers.

There are many products available for cooling system flushing. If a backpressure flushing kit is used, it is recommended that the thermostat be temporarily removed in order to allow free flow to the system with cold water. Always follow the kit or cleaner manufacturer's instructions and make sure the product is compatible with your vehicle.

  1. Make sure the engine is cool and the vehicle is parked on a level surface, then remove the radiator neck cap and, if equipped, the recovery tank cap in order to relieve system pressure.
  2.  
  3. Position a large drain pan under the vehicle, then drain the existing coolant by opening the radiator petcock and/or engine drains. It is also possible to drain the system by disconnecting the lower radiator hose, from the bottom radiator outlet.
  4.  



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Fig. Fig. 10: Periodically remove all debris from the radiator fins


CAUTION
When draining 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 at which point it should be returned to a coolant recycling or hazardous waste disposal sight. Check your local laws for proper disposal methods.

  1. Close the radiator/engine drains or reconnect the lower hose, as applicable, and fill the system with water.
  2.  
  3. Add a can of quality radiator flush.
  4.  
  5. Idle the engine until the upper radiator hose gets hot and the thermostat has opened. This will allow the solution to fully circulate through the system.
  6.  
  7. Drain the system again.
  8.  
  9. Repeat this process until the drained water is clear and free of scale.
  10.  
  11. Close all drains and connect all the hoses.
  12.  
  13. If equipped with a coolant recovery system, flush the reservoir with water and leave empty.
  14.  
  15. Determine the capacity of your coolant system (see capacities specifications). Through the radiator filler neck, add a 50/50 mix of quality antifreeze (ethylene glycol or other suitable formulation) and water to provide the desired protection.
  16.  
  17. Leave the radiator pressure cap off, then start and run the engine until the thermostat heats up and opens; this will allow air to bleed from the system and provide room for additional coolant to be added to the radiator.
  18.  
  19. Add additional coolant to the radiator, as necessary, until the level is within 1 / 2 in. (13mm) of the radiator's filler neck base.
  20.  
  21. Stop the engine and check the coolant level.
  22.  
  23. Check the level of protection with an antifreeze tester, then install the radiator pressure cap.
  24.  
  25. If equipped with a coolant recovery/overflow tank, add coolant to the tank, as necessary to achieve the proper level.
  26.  
  27. Start and run the engine to normal operating temperature, then check the system for leaks.
  28.  

 
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