noisy radiator

[TamP]

Hi Folks, One radiator in the living room, makes a noise like a hammer drill for a few minutes at a time. I have bled the radiator a few times to no effect (no air was evident) , the boiler was changed a couple of months ago and everything has worked fine until last week when this reared it's head.
Any suggestions

 

[FiremanT]

Thermostatic Rad valve?

Change of boiler may have changed direction of flow through rads. Only a problem if you have an omni directional TRV.
Tp prove valve problem, immediately when noise occurs, adjust TRV. If noise stops then valve is the problem. Or adjust valve slowly and you may cause the noise to occur.

Did you have new valves fitted with boiler?

EDIT: Just realised it is August, so above may be completely wrong.

 

[TamP]

It may be August but it's my Mother-in-Law's house. 82 years old and needs the heating on most of the time!! Sauna conditions.
Valves were not replaced with boiler but if the flow had changed wouldn't that affect more than one Radiator?

 

[dilalio]

Take the Trv head off and manipulate the pin up and down a few times. If noise persists but operating the valve affects it then you need the valve replaced.