Cooling Systems


Keeping cool is a major part of enjoyable motoring, so here are some tips to keep you & your car happy …


  • Radiators
  • Air Con

Service Cooling Systems

Flushing coolant

Flushing coolant is recommended by the manufacturer usually every two years or 40,000k's. Over time it weakens to the point that it looses its anti boil/freeze abilities. Coolants other major use is to prevent internal corrosion/electrolysis of the engine and associated cooling system parts. I will use a Gen II liberty 2.2 as the example vehicle for the procedure for flushing coolant. Subaru suggests genuine coolant mixed 1:1 with demineralised water. My opinion is any coolant that is of "Type A" is suitable this is also sold as "VN" coolant in Australasia. 3 litres is usually enough for most Subaru's
1. Remove radiator cap with engine cold, park the car near a tap
2. Disconnect the small hose to the coolant reservoir and allow it to drain into a dish
3. Disconnect any of the heater hoses, one end will do, they have a spring loaded clamp that holds the hose on. You will need to close the clamp with a pair of pliers and slide it back onto the hose. The heater hoses in question are located on the LH side of the firewall. NOTE: Be careful not to crush the heater core, its made of aluminium or copper. Very easy to crush it out of the round shape and make it leak. My suggestion is to loosen the hose off the heater core with a twisting motion, don't use tools on it.
4. Remove all the fittings from one end of your garden hose. This hose will fit neatly up the exposed rubber end of the heater hose. Gently turn on the garden hose so water begins to flow out the radiator.
5. Turn the heater tap so as water flows out the heater core. Some models don't need this as coolant flows through the heater all the time.
6. When the flushing water flows clear its a good practice to start the engine with the hose still flushing, this will create turbulence inside the engine and will hopefully wash out any coolant hiding. NOTE: remove tools before starting engine, only runs engine for a couple of minutes.
7. Remove hose and reassemble. Try to line up the spring loaded type hose clamp with its original position, there are usually marks on the hose. Some time the hose will leak if the clamp is not in the same position.
8. Open the small plastic drain tap on the bottom of the radiator. Allow the clean water to drain out. Earlier models are not equipped with this drain tap, just remove the large bottom radiator hose.
9. Once the clean water is out is time to start adding coolant. There are two ways to do this. First you can mix up a bucket of coolant 50:50 or just add three litres of coolant to the radiator and top up with water. Either method works, the coolant manufacturer's suggest the first method.
10. Fill up the cooling system and start the engine. Allow it to warm with the cap still off. bubbles will come out of the cooling system as the engine warms. When no more bubbles appear install the radiator cap. liberty has a bleed point in the radiator that needs to be opened when at operating temp. Warm the engine further until it reads its normal temp on the gauge. With a screw driver open the bleed point just enough so that coolant {with no air bubbles}appears to ooze out of the bleeder, DONT pull the bleeder all the way out or you will be sprayed with hot coolant. tighten the bleeder only enough so that it won't loosen, its made of plastic so its easy to strip.
11. Test drive for about 10mins, checking the temp gauge constantly. If an air lock is in the system it will appear now, good idea to take water with you just in case. NOTE: Sometimes Subaru's get air trapped under the thermostat inside the engine. This can cause the engine to temporarily over heat until steam opens the thermostat and coolant can flow through the radiator. Stop your test drive allow the engine to cool and top up the coolant only when safe to remove the radiator cap.
12. Check for leaks with the engine hot.
13. Drive the car for a day and recheck for leaks and coolant level. Sometimes more trapped air will appear after repeated driving.

Air con

There are many type of air-conditioning systems out there, some are after market & others factory fitted with different type of gas, so Its' generally good practice to take your car to your friendly mechanic to get it serviced once in a while ( re-gassed ) every couple of years / … ? km to make sure all the seals are lubricated too !

( more to add here )


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