No Hot water in upstairs Heating pipes after draining system

[downco]

I had to change a valve in the bathroom radiator because of a constant leak. I drained the system as best i could and replaced the valve this was done however there seemed to be a lot of water still in the system so maybe it wasnt drained properly, I just used used loads of towels to mop up the spillage.
I refilled the sytem and bled all the radiators
Now for the problem.
Downstairs 4 radiators are all working fine in fact they seem far hotter than normal.
Upstairs 4 radiators are stone cold not even any hot water in the pipes leading up to the valves.
I bled these upstairs radiators and eventually the air went and water came out so i know there is water in them.
Any ideas would be greatly appreciated.
I should say that before the draining the system was working perfectly apart from the dripping valve.
Oil fired boiler with tank in roofspace.

 

[Biguns]

Some useful info here

//www.diynot.com/forums/viewtopic.php?t=175736

Try turning all rads off except one of the problem ones and see what happens If it warms up, go to next problem one etc etc whilst constantly bleeding

 

[downco]

Thank you so much for that, i will have a good read through it. Thank you again.

 

[downco]

Just a short note to give thanks for your reply. The thread was great reading and all is now well in fact all the radiators seem to be warmer and heating up faster.
All in all it is good job, thank you.
Cheers