I currently have no overheating problems, although i may and not know it with the lack of sensitivity that the standard temp gauge has, but recently i have been getting the Waterfall sound.

1. I have read recently about reversing coolant flow to get the air out. Is it the hoses to the reservoir that you disconnect and switch, or something else?

2. Is it better to be a bit over the cold fill line or a bit under?

 

1. You reverse the hoses for the heater core... but this is not necessary if you bleed the cooling system.
2. I don't think it really matters, you don't want to overfill and you don't too little in - the level they give is just fine. Some bright engineer thought that was the right level for some good reason.

 

1. Bleed the system ---> https://landroverforums.com/forum/sh...ad.php?t=23072

2. Fill it to the cap (per DiscoMike)

 

After doing my head gaskets I filled the system via the expansion tank with bleed screw removed then topped off with a small funnel right into the bleed screw orifice. I ran it for about a minute then removed the screw and topped off again. It seems to have worked fine, no gushing and level has remained constant for about two weeks now.