Mazda 323/626/929/GLC/MX-6/RX-7 1978-1989

Oil Cooler

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On all but 1984-85 carbureted engines, the oil cooler is mounted below the radiator. It is equipped with a bypass valve, which does not allow oil to circulate through the oil cooler until the oil temperature reaches 149-158°F (65-70°C). If necessary, the bypass valve may be removed for inspection and/or replacement.

REMOVAL & INSTALLATION



Except 1984-85 Carbureted Engine

See Figures 1 and 2

  1. Drain the crankcase and cooling system into separate containers.
  2.  
  3. Raise the front of the vehicle and safely support it. Block the rear wheels.
  4.  
  5. Remove the under cover and the radiator grill upper cover.
  6.  



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Fig. Fig. 1: The oil cooler is mounted below the radiator-except 1984-85 carbureted engines



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Fig. Fig. 2: Oil cooler positioning on rotary engines

  1. Disconnect the oil inlet and oil outlet hoses from the oil cooler. Drain the lines completely and plug the ends.
  2.  
  3. Unfasten the retaining nuts, then remove the oil cooler assembly. If necessary, remove/install the bypass valve as described later in this section.
  4.  

To install:
  1. Position the oil cooler assembly, and fasten the mounting nuts.
  2.  
  3. Unplug and connect the oil outlet hose to the top of the cooler.
  4.  
  5. Unplug and connect the oil inlet hose, using new sealing washers.
  6.  
  7. Install the radiator grill upper cover and the under cover. The oil cooler should be at a 40-50 degree angle with the under cover to ensure proper air flow across the cooling fins.
  8.  
  9. Lower the vehicle and unblock the wheels.
  10.  
  11. Refill the crankcase and the cooling system to their proper levels.
  12.  
  13. Start the engine and check for leaks.
  14.  

1984-85 Carbureted Engine

See Figures 3 and 4

  1. Drain the crankcase and cooling system into separate containers.
  2.  
  3. Disconnect the inlet and outlet coolant lines from the oil cooler. Drain the lines completely and plug the ends.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: On 1984-85 carbureted RX-7s, the oil cooler is at the base of the oil filter



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Fig. Fig. 4: Be careful to only turn the appropriate fasteners when removing the oil cooler

  1. Disconnect the oil pipe and remove the sealing washer.
  2.  
  3. Unbolt and remove the oil cooler and filter assembly as a unit. Remove and discard the O-rings and filter cartridge.
  4.  

To install:
  1. Assemble the oil cooler with a new filter cartridge and O-rings.
  2.  
  3. Position a new sealing washer, then connect the oil pipe.
  4.  
  5. Unplug and fasten the inlet and outlet cooling lines to the oil cooler.
  6.  
  7. Refill the crankcase and the cooling system to their proper levels.
  8.  

 
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