New welsh plug leaking stopped after engine got hot

[Armand]

Hi, have this happened to anyone before, welsh plug leaked and installed new brass one, cleaned the hole good and tapped in the new plug evenly, afterwards when I tested it when engine got hot it still leaked, left it to cool down till next day and tested again and at operating temp no leaks anymore, can it be that the brass plug have settled after it got hot and expanded, should I be worried that it will start leaking again and why whould the old one have start leaking, there was no corrosion on it?

[VAG Fan]

I've seen micro-corrosion on the plug and the hole that only became visible after rubbing it with a scourer pad (Scotchbrite) and looking at it very closely. This was on the inlet manifold of my Fox. I ended up filling the small pits with a bit of Pratley Steel. I know, it's not good practice to glue Welsh plugs in, but I figured there were enough original ones for emergency pressure relief, and our engines in SA don't really freeze up anyway.

If your new plug has stopped leaking, and you always have enough coolant additive in the system, I think chances are pretty slim that it would start again.

[Armand]

Tested it a few times now not leaking a drop, glad it stopped, that things is a hassle to change when engine isnt taken out, I had to take of the branch, drill a hole through it and made a hook out of roundbar which fitted through the hole in the plug and on to a strong handle on the other side to give me enough leverage to pull it out

[panic-mechanic]

It happens - don't sweat it.