Tinkling sound in vertical radiator

[justinthyme97]

Installed a Bliss Thorpe tall vertical radiator a few months back. Used fully open in the recent cold spell it's developed a tinkling/internal dripping sound. I've bled it a couple of times now but still get the same sound. Got a bit of air out. Due to its tubular design could it possibly be that bleeding needs to be done from both sides? Sounds unlikely I know but the sound does seem to come from the side opposite to the bleed valve. That side is cooler too. It is in a bedroom and consequently easily the highest point in the circuit but well below the header tank. I feel sure its not coming from the valves.

 

[gas112]

yep slightly loosen the nut on other side from bleed these rads can be a nuisance for getting rid of trapped air