Radiator corrosion around blanking plug (photo)

[chris1982]

My radiator is a bit corroded around the blanking plug, see photo - flaking paint, green and white flakes. Do I need a new rad (soon? ) or is there a (temp) fix?
Lately there is some air in the system and I found this as the potential source.

 

[ianmcd]

your rad plug has a very cheap and useless 0 ring in it, take the plug out and wrap PTFE on the threads and it will be fine, as you need to drop the system pressure to do it, do the same at the other end at the same time

 

[chris1982]

Thanks, good to know I should not worry too much about the radiator's main body! (And you are right about the other end - last year I smeared some LX sealer around the outer ring but will now try to swap the bleeding valve too)

 

[Madrab]

shut off both rad valves - count the lockshield turn so it can be put back the same. that way you just need to open the bleed valve and depressurise the rad, not the system, then take both ends off and re-seal.

 

[chris1982]

Thanks everyone! Last night I isolated the radiator (like Madrab said) and replaced the blanking plug and bleedvalve. It seems to have gone well!
But it turns out there was no O-ring on the plug (as ianmcd guessed), but some white paste (set hard), see photo. Is that still common to fail (and about a week after the inhibitor was topped up I heard air bubbles, though it might be a coincidence)?
And the water that came out of the plug hole was quite dirty (other photo), surprising to me as it looks crystal clear at the magna filter and when bleeding elsewhere. Is that just local gunk then?
In any case, the radiator is in a better state now.