Bleeding radiators isn’t working.

[JuanSheetIsPlenty]

Hopefully there is. Simple solution. The 3 upstairs radiators in my house only heat up 1/3 of the way up. Downstairs radiators are all fine. I’ve tried bleeding all three. 2 of them hiss and then the hiss fades and nothing else happens. The other doesn’t hiss at all. I know from bleeding other radiators there is supposed to be a spluttering of radiator water but this doesn’t happen. So I just tighten the valve again. The radiators don’t heat up any higher up though. Am I just not leaving the valve open for long enough? I’ve never bled a radiator where the hiss didn’t lead to water spluttering.

Once you've bled the rad, you may need to top up the pressure in your heating system. Depending on your boiler type, there will usually be a tap and pressure gauge for this, near your boiler. Here's a YouTube video to start you off:

Thanks mirena. It’s an oil fired boiler rather than gas- but I assume same solution? I’ll have a search to see how to top up the pressure on it.

If the pressure is ok, then the system may be gummed uk with sludge. Call the plumber as you will probably need the whole system flushed out

Yes, would be same solution, as either way your radiators are filled with water. If air has got in, that suggests poss a small leak somewhere, but in the first instance you just top it up and monitor it.
It wouldn't be sludge @MarieG10 because that makes radiators cold at the bottom where sludge accumulates, but hot at top of water can flow there. Air or low pressure causes you to have heat at bottom but not at top.

Does your boiler have a pressure gauge on it?

Or is it a more traditional type where the water is topped up from a small tank in the loft (I think it is).

How deep is the water in this small tank?
And how deep is the layer of brown mud?