exhaust manifold drain plugs full of rust
Reviving this thread...
So my exhaust manifold drain plugs threads are full of rust so I can't get my plugs to go in even a quarter turn. I knew I was on borrowed time as each year when I winterized they went back in less and less (and I didn't think to replace the plugs but in hindsight, as maybe that would have helped???). I think this last summer was the end of the line as I could see there had been some leakage over the course of the season and fear this summer could be worse. So I could use some help/suggestions.
Is there something I can put in there to eat out the rust so that I can regain some of those threads? Or re-tap the threads? I've read that I shouldn't force the brass plugs in there (but since I didn't see that first I tried and ended up only stripping the threads of my brass plugs). It is mainly at the bottom of the threads where the water has rusted over time. I tried picking at it with a screwdriver and was able to remove some of it, but not enough to really get my plugs to go in. Any thoughts or suggestions would be great (short of replacing the manifolds would be even greater!).