Freeze Plugs

[devovino]

Just a quick few questions about what I am assuming are "freeze plugs" on the cooling manifolds.They were removed last year for winterization. I just tried to re-thread them back into the manifolds, one only went about half way without over forcing it( I think its may be due to either some corrision on the threads, and a sticky substance the PO put on the threads, probably some kinda plumbers putty) and the other started to thread, then refused to thread correctly, I did not want to cross thread them it and really bugger up the threads.
Do I need to wire brush all of the corrision form both sides of the threads? Re-thread the female threads (tap and die) or do people usually buy new freeze plugs? ANyways, hope this makes sense, and I can find a good way to thread them back in and start this motor up! ready for some lake time!

[michael hunter]

I think they are 1/2 '' National Pipe Thread. You should be able to get a tap for it at the hardware store to chase the threads. They are a tapered fit so dont run the tap all the way in. Plug should also only go in about 1/2 -3/4 of the way in.

[devovino]

Thanks, that was also another question I had, if it threaded all the way in. I was unaware how far to "screw" it in. I am glad you mentioned that! Well I might to clean the threads with a wire brush if I can't start it by hand, I will chase it.

[beast 496]

The plugs you are refering to are the drain plugs, the thread size is 3/4 NPT This is a tapered thread ie; pipe fitting threads. The plugs should be brass on the newer engines and steel on the older. You can clean out the threads with a short tap if you have one or manually clean out the threads. Al