Help with ST170 thermastat blanking plug

[Chippa]

Hi, I just registered to forum but have had my st170 quite some time now,

Need Help with the blanking plug on thermastat housing if you could help?. It as had a slight leak there before and i did buy new blanking plug from ford

But it did not fit was loose fit,maybe slight warp or hole got bigger?Not sure.I have repaired it before and it stopped leak,Then after some time it returned.Now i don't want to spend money on new housing because housing not the problem.

My question is can this blanking plug be cleaned and dried and would epoxy resin work to glue/seal it in for good? I got some gorilla epoxy resin,Which says withstands extreme temps,Water proof and fills gaps.Anyone no if it would work?

I am changing water pump and aux tensioner so while coolant drained would like to try fix this plug.

Thanks in advance for any help