Crashclint on RL offered the best air bleed routine I have seen for those who do not have an Airlift.Here is a quote:
"I do know if you didn't get all the air out of your coolant system temperature will bounce around when it hits an air pocket. I followed the steps below when I change the pump in my Boxster. On the advice of a Porsche mechanic, if the temp light comes on, turn the car off and let it cool awhile before starting the procedure again. Mine did come on during the process so I let it cool for about an hour and went back to it. This process should be a little easier on the 996, less to remove.
1. Consider covering the trunk with plastic in case of a coolant overflow.
2. Remove the radiator cap, oil filler cap, and dipstick.
3. Pop the cover trim plate off the filler access area. This reveals the bleeder valve. If you remove the little screw above the trim plate to do this, be extremely careful to not drop the screw into any of the filler necks.
4. Flip the bleeder valve locking clip up to release it.
5. If you have an automatic transmission, remove fuse B1 (the ATF cooler valve).
6. Fill with coolant up to the bottom edge of the filler neck.
7. With the engine idling, occasionally revving the engine, fill up with coolant until there's no more room when the engine is revved. (Revving may raise the level a bit.)
8. Replace radiator cap.
9. Warm up engine until you are sure the thermostat is open. 10 minutes at 2500 RPM should do it, and you should hear the radiator fans come on.
10. Run 5 more minutes at 2500 RPM, revving to 5000 RPM every 30 seconds.
11. Carefully open the radiator cap, and top up the coolant.
12. Replace the radiator cap.
13. Run 5 more minutes at 2500 RPM, revving to 5000 RPM every 30 seconds.
14. Idle until the radiator fans cycle on and off once.
15. Carefully open the radiator cap, and top up the coolant.
16. Put everything back the way it was. "
If you are replacing the tank this diy may help.Lots of photos +tools:
http://www.pedrosgarage.com/Site_3/Replace_Coolant_Reservoir.html