engine block coolant drain plug - sealing

I've replaced the coolant drain plug in my engine block. Foolishly, I went to use the old one and found it was only keeping coolant in because it was clogged up behind it. Once I cleared that the coolant ran out and I couldn't stop it because the thread on the t-piece of the tap had stripped long ago.

I bought a new one from Turner. The end of the t-piece wouldn't seal, I could blow through it. They told me as it's brass to tighten it up hard a few times to get it to seal. That didn't work, so I taped up the inside end. There goes using it as a tap, might as well use a bolt..

Now it leaks around the outer thread. Only 3 or 4 drips in fifteen minutes of running and there's nothing of note on the garage floor each morning. I've used PTFE tape to get it this good.

Will it improve as it clogs up behind it again over time? Am I expecting too much?

There's a faint groove in the block exactly where the drips run so I wonder if trying to stop this entirely is trying to stop something that's been happening for decades..

I always rely on gunge to seal slow leaks, it can take ages but eventually it works. Some proprietary coolant sealant like rad weld might do the job a lot quicker but many don't recommend such tricks.

Col

I had a mini years ago that leaked coolant from the drain tap at the bottom of the radiator. I used body filler to stop it and it worked for all the time I had the car.

Col

If you are replacing the tap with a bolt use a brass plug. Rusting in a steel bolt threads may result in later problems.

I have an old bottle of this from my days as a gas engineer will seal up even the coarsest thread.
https://www.ebay.co.uk/itm/Loctite-...376276&hash=item4220239d3d:g:g9sAAOSwAadfWg~K

@Blackburn would you use ptfe tape with that stuff as well? I haven't used loctite products before.

No need for ptfe tape wih the loctite.

Ok. Can I wind it in with the loctite wet while coolant is still trickling out or is it better if the thread is as dry as possible when I do this?

I'm thinking about switching to a drain bolt with a crush washer, and this loctite, and then never touch the thing. I can flush the block through in other ways, these taps just seem like something to go wrong when you least want it.

https://www.johncraddockltd.co.uk/569047-drain-plug-for-radiator-and-cylinder-block.html

Plug is what I would fit.
If you want to stop the final trickle jack/tilt the truck on that side.

Pretty sure a little coolant will not be a problem the sealant is activated by pressure when screwed in. Can be removed at a latter date without any issue.
First came across it when I had a plant leaking air on Total Oil St Fergus site leaking compressed air one of ther engineers got me a bottle from there stores fixed the leak that well it was there for about 5 years. Bought myself some to carry in company van renewed whenever bottle got low , current bottle is one I had when I retired in 2012 and it still works ok.

With that sort of leak I would be tempted to use Boss-White plumbers sealant rather than PTFE tape. ;-)