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classic.car.fan

how to "burp" cooling system?

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i have air in my mark v's cooling system. i thought i just put a funnel in the radiator and fill it with coolant and run the car? someone told me if i do that i could warp the heads or blow the head gasket? how should i do it? thanks

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Fill the rad and put the cap on loose ( do not tighten it down). Start the engine and run for a few minutes. Check the rad and top it up. Do not fill to overflowing, just so you can see the coolant. When the thermostat opens and the coolant starts to circulate you may see the coolant in the rad stir around and go down, and the top rad hose get warm. At this time you can top off the coolant and put the cap on for keeps.

Check that the overflow jug is full to the lower "cold" line. Check it every day or two, it may go down. When it stabilizes you know the coolant is completely full and should stay that way. After that you can check it when you check your oil but it should not go down much if at all.

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I've found that some cars just tend to trap air in the cooling system. The most effective method I've found (short of using the vacuum fill mechanism designed for later model cars) is to jack the front of the car so that the radiator fill opening is as high as possible. Run the engine this way with the radiator cap off until the coolant starts to expand, shut off the engine, and top off accordingly.

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I would also suggest you turn the car's heater on while filling and warming it up to make sure the water is circulating through the heater core as well to eliminate any potential air pockets in the heater core circuit.

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Fill the cooling system as usual; then loosen the temperature sender on the intake manifold. If there is air trapped in the block or heads it will sputter out around the threads of the sender. When coolant starts to leak out around the sender tighten it back up and you are good to go.

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Yes, As long as the coolant is above the head. On older vehicles, we use to just loosen the upper heater hose and wait until you see antifreeze. Best to have the level above the thermostat/head. Then you know your safe. Always run the engine up to temp and see that it is circulating. Add coolant as necessary. Dandy Dave!

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