I've just replaced the upper/lower radiator hoses on my 1989 240 wagon. I followed the bentley manual. I didn't use the drain cock but did loosen it off to make sure coolant had reached it. I let the car run and it really creeps up toward the high temp mark. The thermostat should bleed the air right? I added a jug and a half of Prestone coolant to the system. Is that enough? I know it holds 9 litres using the drain cock method. In the process of putting a jug underneath I ripped off some of the rusted pre heat hose off. Do I need it? Thanks