Mitsubishi Galant/Mirage/Diamante 1990-2000

Cooling System

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FLUID RECOMMENDATIONS



A good quality ethylene glycol based or other aluminum compatible antifreeze is recommended for use in the vehicles covered by this guide. It is best to add a 50/50 mix of antifreeze and distilled water to avoid diluting the coolant in the system.

LEVEL CHECK





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Fig. The coolant level should be between the FULL and LOW levels on the coolant recovery tank

The coolant recovery tank is located in the engine compartment, typically on the fender well.

The proper coolant level is slightly above the FULL COLD marking on the recovery tank when the engine is cold. Top off the cooling system using the recovery tank and its marking as a guideline.


NOTE
Never overfill the recovery tank.

A coolant level that consistently drops is usually a sign of a small, hard to detect leak, although in the worst case it could be a sign of an internal engine leak. In most cases, you will be able to trace the leak to a loose fitting or damaged hose.

Evaporating ethylene glycol antifreeze will have a sweet smell and leave small, white (salt-like) deposits, which can be helpful in tracing a leak.


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

TESTING FOR LEAKS





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Fig. A visual inspection for leaks will sometimes find a leak. This photo shows evidence of a leak at the upper radiator hose-to-thermostat housing junction



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Fig. Remove the recovery tank cap to allow the pressure tester to be connected to the system



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Fig. This cooling system requires a threaded adapter for the recovery tank to allow the pressure tester to be connected



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Fig. Thread the adapter onto the recovery tank



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Fig. Pump the cooling system with pressure, making sure not to overpressurize the system or damage can occur



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Fig. Watch the gauge on the system and observe the pressure reading

If a the fluid level of your cooling system is constantly low, the chances of a leak are probable. There are several ways to go about finding the source of your leak.

The first way should be a visual inspection. During the visual inspection, look around the entire engine area including the radiator and the heater hoses. The interior of the car should be inspected behind the glove box and passenger side floorboard area, and check the carpet for any signs of moisture. The smartest way to go about finding a leak visually is to first inspect any and all joints in the system such as where the radiator hoses connect to the radiator and the engine. Another thing to look for is white crusty stains that are signs of a leak where the coolant has already dried.

If a visual inspection cannot find the cause of your leak, a pressure test is a logical and extremely helpful way to find a leak. A pressure tester will be needed to perform this and if one is not available they can be purchased or even rented at many auto parts stores. The pressure tester usually has a standard size radiator cap adapter on the pressure port, however, other adapters are available based on the size of the vehicle's radiator neck or recovery tank depending on where the pressure tester connects. when pressurizing the cooling system, make sure you do not exceed the pressure rating of the system, which can be found on the top of the radiator cap, however, if you have and aftermarket or replacement cap that does not have the rating on it, 16psi is a standard to use but some cars are higher. Overpressurizing the system can cause a rupture in a hose, or worse, in the radiator or heater core and possibly cause an injury or a burn if the coolant is hot. Overpressurizing is normally controlled by the radiator cap which has a vent valve in it which is opened when the system reaches it's maximum pressure rating. To pressure test the system:


NOTE
The pressure test should be performed with the engine OFF .

  1. Remove the radiator or recovery tank cap.
  2.  
  3. Using the proper adapter, insert it onto the opening and connect the pressure tester,
  4.  
  5. Begin pressurizing the system by pumping the pressure tester and watching the gauge, when the maximum pressure is reached, stop.
  6.  
  7. Watch the gauge carefully and see if the pressure on the gauge drops, if it does, a leak is definitely present.
  8.  
  9. If the pressure stayed somewhat stable, visually inspect the system for leaks. If the pressure dropped, repressurize the system and then visually inspect the system.
  10.  
  11. If no signs of a leak are noticed visually, pressurize the system to the maximum pressure rating of the system and leave the pressure tester connected for about 30 minutes. Return after 30 minutes and verify the pressure on the gauge, if the pressure dropped more than 20%, a leak definitely exists, if the pressure drop is less than 20%, the system is most likely okay.
  12.  

Another way coolant is lost is by a internal engine leak, causing the oil to be contaminated or the coolant to be burned in the process of combustion and sent out the exhaust. To check for oil contamination, remove the dipstick and check the condition of the oil in the oil pan. If the oil is murky and has a white or beige "milkshake" look to it, the coolant is contaminating the oil through an internal leak and the engine must be torn down to find the leak. If the oil appears okay, the coolant can be burned and going out the tailpipe. A quick test for this is a cloud of white smoke appearing from the tailpipe, especially on start-up. On cold days, the white smoke will appear, this is due to condensation and the outside temperature, not a coolant leak. If the "smoke test" does not verify the situation, removing the spark plugs one at a time and checking the electrodes for a green or white tint can verify an internal coolant leak and identify which cylinder(s) is the culprit and aiding your search for the cause of the leak. If the spark plugs appear okay, another method is to use a gas analyzer or emissions tester, or one of several hand-held tools that most professional shops possess. This tools are used to check the cooling system for the presence of Hydrocarbons (HC's) in the coolant.

DRAIN & REFILL





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Fig. The draincock is usually located at the bottom of the radiator



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Fig. Gently rotate the draincock counterclockwise to open the draincock . . .



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Fig. . . . then allow the coolant to drain out of the radiator and cooling system



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Fig. Allow the fluid to drain until it stops and tighten the draincock hand tight



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Fig. Make sure to heed the caution on the radiator cap and NEVER open the cap when the engine is hot



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Fig. Grasp the radiator cap and rotate it counterclockwise . . .



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Fig. . . . to remove the cap from the radiator



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Fig. Pour the proper 50 / 50 coolant mixture into the radiator . . .



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Fig. . . . make sure to fill the coolant recovery tank to the proper level also

Ensure that the engine is completely cool prior to starting this service.


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Remove the recovery tank or radiator cap.
  2.  
  3. Raise and support the vehicle.
  4.  
  5. If necessary, remove the splash shield from under the front of the vehicle.
  6.  
  7. Place a drain pan of sufficient capacity under the radiator and open the petcock (drain) on the radiator.
  8.  


NOTE
Plastic petcocks easily bind. Before opening a plastic radiator petcock, spray it with some penetrating lubricant.

  1. Drain the cooling system completely.
  2.  
  3. Close the petcock.
  4.  
  5. Remove the drain pan.
  6.  
  7. If necessary, install the splash shield under the vehicle.
  8.  
  9. Lower the vehicle.
  10.  
  11. Determine the capacity of the cooling system, then properly refill the system at the recovery tank and radiator with a 50/50 mixture of fresh coolant and distilled water until it reaches the FULL COLD line.
  12.  
  13. Leave the recovery tank or radiator cap off to aid in bleeding the system.
  14.  
  15. Start the engine and allow it to idle until the thermostat opens (the upper radiator hose will become hot). The coolant level should go down, this is normal as the system bleeds the air pockets out of the system.
  16.  
  17. Refill the system with coolant to the proper level.
  18.  
  19. Turn the engine OFF and check for leaks.
  20.  



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

FLUSHING & CLEANING THE SYSTEM



  1. Drain the cooling system completely as described earlier.
  2.  
  3. Close the petcock and fill the system with a cooling system flush (clean water may also be used, but is not as efficient).
  4.  
  5. Idle the engine until the upper radiator hose gets hot.
  6.  
  7. Allow the engine to cool completely and drain the system again.
  8.  
  9. Repeat this process until the drained water is clear and free of scale.
  10.  
  11. Flush the recovery tank with water and leave empty.
  12.  


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Fill and bleed the cooling system as described earlier.
  2.  

 
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