Volvo Coupes/Sedans/Wagons 1970-1989 Repair Guide

Cooling System

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FLUID RECOMMENDATION AND LEVEL CHECK



See Figures 1, 2 and 3

Check the coolant level at fuel stops on all models. 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 off the system, as air might become trapped in the system and reduce cooling efficiency. Top off the system with a mixture of 50% antifreeze and 50% water; use this mixture all year round. If the engine is warm when you top off the cooling system, remove the filler cap slowly in order to allow any excess pressure to escape.



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Fig. Fig. 1: Check the coolant level at fuel stops-it should be between the "MAX" and "MIN" marks



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Fig. Fig. 2: Remove the expansion tank filler cap only to add fluid


CAUTION
Always check or add fluid at the expansion tank. NEVER remove the cap from a hot radiator. You can be badly scalded by steam and hot liquid.



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Fig. Fig. 3: Use a funnel to add a 50/50 coolant and water mixture. This ratio should be used year-round

DRAIN AND REFILL



Perform this operation with the engine cold.

  1. Raise and safely support the front of the car on jackstands.
  2.  
  3. Remove the gravel shield, if equipped. Remove the expansion tank cap and set the heater controls to Hot.
  4.  


CAUTION
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 can be reused unless it is contaminated or several years old.

  1. Open the petcock on the right side of the engine block on all but the V6 engine and the diesel. The V6 engine petcocks are located on both sides of the block. The diesel engine does not have an accessible block drain and must be drained at the radiator. If the coolant is to be reused, collect it in a clean pan.
  2.  
  3. On all models, while the block is draining, disconnect the lower radiator hose and allow the coolant to drain into another pan. 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.
  4.  
  5. Close the petcock(s), reconnect the lower radiator hose and add coolant to the expansion tank until coolant is level with the MAX mark on the tank.
  6.  
  7. Run the engine to normal operating temperature and check for leaks. Check the coolant level and refill if necessary.
  8.  

FLUSHING AND CLEANING THE SYSTEM



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

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

Volvo specifies that the cooling system on diesel engines must be bled after refilling the cooling system. This eliminates trapped air from the system and insures proper operation.

To bleed the diesel cooling system, perform the following:

  1. Disconnect the upper hose running to the cold start device on the right side of the engine.
  2.  
  3. Place a drain pan under the hose and hold the hose approximately at the same height as the top of the expansion tank.
  4.  
  5. Fill the cooling system through the expansion tank, then start the engine and run at fast idle.
  6.  
  7. Run the engine for five minutes and continue to fill the cooling system during this time. Reconnect the hose to the cold start device.
  8.  
  9. Continue to fill the cooling system until the correct level is reached, then reinstall the cap on the expansion tank.
  10.  

 
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