Radiator Tails 'gunk'

22 Feb 2006
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United Kingdom
Hi All,

All of the radiators in my house have this crumbly gunk around the radiator pipe (where it fits into the radiator) - I've attached a picture to show what i mean. I presume this was some kind of old seal (house built in the 90s?). A couple of these joints are weeping ever so slightly, not enough to drip but wet on the finger.

My intention was to drain the system down, clean up the joints, apply PTFE and/or plumbers mate and refit. Will that suffice?




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Hard to tell from the blurry pic but just looks like metal corrosion to me, probably caused by the weeping.

I wouldn't be too excited about taking that tail off as it might not go back in.
My intention was to drain the system down, clean up the joints, apply PTFE and/or plumbers mate and refit. Will that suffice
Yup, bit of wire brushing, new tape and they should be fine. As East mentions though, just be careful removing, if they have tape on them though the threads should move.
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Thanks for the replies!

Oilboffin - it could well be actually. It looks almost like cloth - would that be hemp?

Oddly enough I had a plumber around yesterday with a view to get the connections cleaned and refitted. Instead he went away and is going to quote me for 15 new radiators. I had a look just now, there isn't any corrosion on any of my radiators, only the radiator tails but he seemed to think this was the only fix.

I've attached a slightly clearer picture at higher resolution....


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  • Rad Pipe.jpg
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Radiators don't normally corrode on the outside.

If the radiators are working efficiently then just clean the joints.
Yup, it's hemp and white by the looks of it, get the tails out, clean them up, some PTFE tape on them and re-insert. If your rads are working fine with no rust then no need to replace until the chap proves that the tails are stuck fast and can't be removed.Even then if they won't come out they can still be cleaned up with a wire rush and painted, personally I'd show the chap and his 15 new rads the door.

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