Coolant drain/refill

I've just been draining the coolant on my 4.0 P38 by following the procedure in rave but something doesn't seem right.

I only got around 2 litres out of the radiator drain plug even though rave says the cooling system holds 11.3 litres. I'd expect it to be slightly less than that but surely not by that much? I have been loosing coolant but I've been topping it up all the time but it can't of been running with only 2 litres of coolant without overheating can it?

When refilling the coolant the coolant level dropped really slowly, taking at least a minute to go from the top of the expansion tank to the bottom. Should it pretty much empty the tank instantly while filling up?

I had a quick look at most of the pipes to check there wasn't anything blocked or similar and I didn't find anything. The only pipe I haven't checked for a blockage is the one going from the expansion tank to the thermostat because I didn't have time tonight but I plan to look at that tomorrow.

Any ideas what could be wrong or is this normal?

Thanks,
Jack

2.3 from just the rad is about right, don't forget that all the system is 11 litres, that includes the heater, pipes, engine block, manifold, heads, expansion tank etc....

I drained mine a few weeks back and got half a bucket full (maybe 10 litres...) just by leaving the plug open for 10 minutes of so..
You could remove the leads with collectors on hand just in case.. and if nothing comes out then you should be OK to work depending on what you're doing