Thread: Bleeding the cooling system

depends on which car

Sorry,

It's a discovery 1 3.9l v8 1996

They are usually pretty good at bleeding themselves. The small black hose from the back of the thermostat to the top of the radiator allows air to be expelled to the filler plug area of the radiator.

Method: With the front of the car slightly higher than the back, fill both the radiator and expansion tank to a few inches below full, start and run the engine for a minute at over 2500 rpm, observing that coolant is flowing out of the small hose into the filler plug area of the radiator, then turn it off and top up the radiator. Refit the radiator filler plug, fill the expansion tank and take it for a run long enough to open the thermostat. Stop, let it cool down and check the expansion tank level is above the marker inside it.

For the first time in my life I got an air lock in my td5 disco. It happened when replacing the radiator. There was a bleed screw in my high point on the top hose but the only way to properly bleed it was either a full vacuum and charge from a dealer or once I had a full expansion tank was perform cpr on the tank and blow with my mouth all the water into the system until I had no more air hissing out the bleed screw. Wasn't hard but didn't taste good but worked a treat. The other option if your just using a hose to fill er up is open a bleed screw if you have one and put the hose into the expansion tank and turn it on with a rag around the opening so all the pressure flows into the system and forces all the air out. Once it's full just siphon off the extra out of the expansion tank and voila.