Volvo 240/740/760/780/940/960 1990-1998

Cooling System



See Figures 1 and 2

Volvo's all-weather antifreeze Type C (blue-green color) or equivalent should be used on a year round basis. The cooling system should always contain 50% antifreeze solution and 50% water. Studies have shown that extremely weak antifreeze solutions (10-20%) provide poor rust protection, while antifreeze solutions in excess of 70% provide less effective boil over protection.

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Fig. Fig. 1: A tag is usually placed on the expansion tank or the strut tower indicating the type of coolant to be used

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Fig. Fig. 2: Volvo recommends mixing 50% coolant and 50% water to fill the cooling system


See Figure 3

The coolant level should be checked at every 5,000 mile (8,000 km) intervals. The level should appear between the maximum and minimum marks of the translucent expansion tank. Do not remove the expansion tank filler cap except to top up the system, as air might become trapped in the system and reduce cooling efficiency. Top up the system with a mixture of 50% anti-freeze and 50% water; use this mixture all year round. If the engine is warm when you top up the cooling system, remove the filler cap slowly in order to allow any excess pressure to escape.

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.

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Fig. Fig. 3: The expansion tank is marked with MIN/MAX levels; the fluid should be between them


See Figures 4, 5, 6, 7 and 8

It is recommended that the coolant be replaced at 30,000 mile (48,000 km) intervals. Perform this operation with the engine cold.

  1. Remove the expansion tank cap and set the heater controls to HOT .
  3. Raise the vehicle and support it safely.
  5. Open the petcock on the bottom of the radiator. If the coolant is to be reused, collect it in a clean container.
  7. Completely drain the radiator of all the coolant.
  9. Close the petcock and lower the vehicle.
  11. On models with an expansion tank, either use a siphon or unfasten the tank and hold it up so that all of the coolant in it flows into the radiator.
  13. Add coolant to the expansion tank until coolant is level with the MAX mark on the tank.
  15. Start the engine and let it idle until normal operating temperature is reached and check for leaks.
  17. Bleed the cooling system by leaving the cap off the expansion tank and the vehicle reaches normal operating temperature. The atmospheric pressure will aid in the removal of air pockets from the system.
  19. Check the coolant level and refill if necessary.
  21. Install the expansion tank cap.

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Fig. Fig. 4: The radiator petcock is accessible through an opening in the gravel shield

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Fig. Fig. 5: Loosen the petcock using the proper size tool; most vehicles require a 6mm Allen head wrench

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Fig. Fig. 6: After the petcock is loose, coolant will start to drain out

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Fig. Fig. 7: When the coolant is drained, remove the petcock, then clean and inspect it before installation

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Fig. Fig. 8: Pour the proper 50/50 coolant mixture into the expansion tank to refill the system


  1. Proceed with draining the system as previously outlined.
  3. When the system has drained, reconnect the hoses and secure as necessary.
  5. Move the temperature control for the heater to its hottest position; this allows the heater core to be flushed as well.
  7. Using a garden hose, fill the radiator and allow the water to run out the engine draincocks. Continue until the water runs clear.
  9. Be sure to clean the expansion tank as well.

If the system is badly contaminated with rust or scale, you can use a commercial flushing solution to clean it out. Follow the manufacturer's instructions. Some causes of rust are air in the system, failure to change the coolant regularly, use of excessively hard or soft water, and/or failure to use the correct mix of antifreeze and water.

  1. After the system has been flushed, continue with the refill procedures outlined above.
  3. Check the condition of the radiator cap and its gasket, replacing the cap if anything looks improper.