Leaking radiator

[BrianD3]

Basic plumbing question for gubu - I have a radiator with a pinhole near the top. If I close the inlet valve will the leak stop or slow down or will it make no difference. I can close the inlet valve and know it will stop the rad getting hot but will cold water continually backflow into it and come out the top?

I am wary of going near the outlet valve as it has a plastic cap on it, is very tight and hasn't been turned in probably 40 years.

Also I have Unibond epoxy putty for metal, will this fill the pinhole at least temporarily?

Thanks

[Fratello]

Closing the inlet will not slow the leak. The system pressure will come in on the outlet side too.
The unibond could vey well solve the problem but a new rad is needed since there could be a heap of other locations within close to leaking.
I'd say take the lid off the outlet valve (lockshield valve) anyway and have a suitable tool at hand in case you need to close it in a hurry.

[BrianD3]

Thanks Fratello, I'm not sure how well the Unibond will stick to wet metal but will give it a go.

[kadman]

If you know where the pinhole leak is, solder it.

[BrianD3]

I tried the epoxy, no joy, the fact that I was trying to fill an actively leaking wet hole was probably the reason. Anyhow,I have now managed to close the outlet (it only took 1.5 turns?) so hopefully that valve is working and the leak will stop shortly. Small rad, single, about 160 cm wide by 50 cm tall and the leak is about two inches from the top. To kadman, I don't have any soldering equipment or skills but I'll look into it.

[kadman]

JB Weld , Liquid metal, or similar available from any motor factor, and no tools required except sandpaper to clean the area of the leak

[knownunknown]

Not knowledgeable at all but some internet sleuthing reveals that fixing it will probably only be temporary as the rad must have begun to rust from the inside out, maybe it needs replacing.

This product apparently seals the rads for you but again this is probably a temporary fix(if it even works https://fernox.ie/product/leak-sealer-f ... %20devices.)

Other advice recommends to drain the rad dry first before attempting to fix. Needs to be dry for the epoxy to work.

Good luck, doesn’t sound like an easy problem if you are not an expert.

[BrianD3]

Thanks, I'm currently letting it drip away. Bleed valve also open and slowly dripping. Closing the lockshield appears to have isolated it from the system as I'm not now seeing any pressure drop on the system pressure gauge.

Ultimately, that rad and probably several other 40 year old rads in the house may need replacing soon. Also, from what I've read a leaking (non isolated) rad can contribute to bigger problems by encouraging corrosion in the system and boiler as air is getting in, water getting out and the system is being being topped up with fresh oxygenated water.