Leaking radiator

Dear Skekid. If it's a lockshield valve remove the plastic knob and see if the gland is leaking (it's a small nut the shaft passes through). Often these leak especially if the valve is turned on and off frequently. This drip running down can sometimes be mistaken for the lower olive / nut leaking. It's an easy fix for any plumber and does not require a drain down. Hope this helps, Bob.

Try to tighten it up. If that doesn't work then I would recommend to drain the system (in order not to flood the place) and replace ether just the olive or put a whole new valve. Tighten the nut up and represurise the system.

Try nipping the nuts up if not drain down and replace valve .

It'll either be a lockshield valve or a TRV (thermostatic radiator valve). If the leak is coming from the nut at the bottom which connects the valve to the pipework, or the nut that connects to the stem coming out of the rad. You may be able to tighten them slightly to stop minor leaks. Grip the valve body while tightening to stop the valve moving. If it's coming from the stem that goes into the radiator, or the valve body itself, then the system would have to be drained. A simple process but would need some knowledge. An easy straight swap once the system is empty of water.

It could be a T R V Valve or A locksheild type