fUEL TANK SUMP PLUG

hurkur

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I am draining my diesel tank and removing the drain plug in it's sump. My question is what to use around the thread of the drain plug to seal it.
 
Presumably then a tapered plug.

If the thread in the hole is also tapered a good diesel resistant thread sealing compound should be adequate but thread seaing tape can be used

If the hole has a parallel thread ( bad engineering but a common plumbing practice) a thread seal tape is probably your only option.

You will need sufficient tape to seal the joint but not a big excess that could become a nuisance if bits find their way into the fuel system although hopefully you have the usual traps and filters that would catch them.
 
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Sump thread

thanks for your reply VicS. I have a feeling that it's a tapered threaded plug in this tank that is fitted to my Westerly. Could you recommend a sealant that could be used and is resistant to diesel.
 
Hylomar is more suited to joints where a very thin film is required. It is excellent in this situation.

With threaded joints like these there are significant spiral leak paths between the peaks of one thread and the root of the other which needs to be bunged up... even if we are talking about tapered into tapered threads

If the female thread is parallel it would be best to get a shouldered plug that can be tightened onto a fibre or annealed copper washer.

If it is a tapered plug into a parallel female thread then there are so few threads in good contact that I think tape is the best choice.

Personally I'd probably use tape anyway on a tapered plug, but if I was using jointing compound it would be Foliac Super Red ...because it is suitable and I have a big tin of it! For this job more suitable than Hylomar IMHO.
 
Bowlsboat

When I drained mine I replaced the plug with a tap so that I can drain off a sample of the fuel easily and if I need to empty the tank again it will be easy to get the last drops out into a container. I locked the tap with a piece of wire so that it cant turn on accidentally. No problems and its been like thay for twenty years.
 
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