How do you bleed a Nissan Serena cooling system?

You can download the complete workshop manual from Tradebit.com for about 5 dollars. Tells you the specifics of refilling and bleeding the system Basically you have to open air relief valves on the heaters and engine, fit a transparent tube to the engine one to monitor the level, fill via the front heater filler until it comes out of the rear heater air relief valve. If you haven't got a rear heater, I presume you wait until it comes out of the engine one. Run hot as usual and top up via the filler neck. You get the message, better to follow the manual! Hope this helps.