Radiator drain tap

[alanworland]

Draining my sidevalve MM using the radiator drain valve I found it very tight to turn. Did manage to open the valve and it drained well.
Unscrewed it from the radiator and dismantled it, all looked good and it seemed it was 'just sticky'. Thinking about it I probably applied a graphite grease on assembly many moons ago which had now gone gummy.
It's a tapered on/off brass valve. Should this be lubricated?

Alan

[svenedin]

You could lubricate it with Silicone grease as used in domestic plumbing such as brass shower cartridge O-rings etc. It will not go hard and gummy nor will it harm rubber should it find its way into the cooling water (say if you drained and re-used).