i have a plugged hole in my cooling system head???

[Deborah Alms]

Hi everyone,

Hope all had a great holiday!!

I am a new boat owner

I started out with a very small bubbly leak on the top of my motor under the the hose on top of the motor that runs from the port side of the block to the thermostat, when I wire brushed the rust off, i found an unusual situation...

It appears that at one time a hole was bored and a plug was put in? When i cleaned off the rust, there was a very shiny silver round section about the size of a nickel. As i cleaned it more, the plug or whatever it is deteriorated now i have a really nice big hole!

I have a pic on my phone i can forward someone if necessary.

I was wondering if anyone can help me with options?

Sincerely,

Deborah

[msauntry]

Welcome Deborah,

I know those things as "freeze plugs". Why they are called that I don't know... You can pick them up at auto part stores for about a buck each. Measure the sizes, but I think it was a 7/8" plug.

Pry out the old one and press in a new one. Easy enough to say, but the devil is in the details. I haven't done this, so hopefully a more experienced hand can chime in but I think you should have clean metal so take a wire brush to the lip where it sits and get it smooth. I think you can mix a little JB Weld or MarineTex and butter the edge and then press the new plug in. This would be to seal it and prevent leaks.

There are a few freeze plugs on the engine but I can't remember how many. I think there's another on the opposite side of the head as well as by the coil.

[rigspelt]

Can you post a photo so we can be certain about the hole you are describing? I thought freeze plug too, but...

[Pater]

freeze plug?

Many moons back I had to replace freeze plugs and found that drilling a small hole in the middle and screwin in a #10 sheet metal screw made prying out the partially popped plug easier. Next clean and make sure the inside seating edge is smooth and clean. The new plug is slightly domed. Insert it into the hole with the domed side out (yes you can "butter the edge with some sealant", but that just makes it harder for the next time you have to replace the plug) Now with the plug held firmly in place with a small ball pien hammer, whack that hammer head (centered on the plug and the dome will deform causing the outside diameter to increase and seal itself into the casting hole. You'll see a small dimple in the plug's center that'll tell you you've got it set.

[rigspelt]

Don posted a FAQ here on the plugs: http://www.moyermarine.com/faq/6.15.html