How tight should freeze plug fit before flattening?

[kylemorley]

Got some Dorman freeze plugs at the local auto parts and
removed the old ones, cleaned up the seats really nice with a
wire brush on my drill, only to find that the plugs don't even
begin to go in the holes - I pound them awhile, they seem to be
going in, then when I stop pounding they fall out.

I cleaned up the edges a bit with emery paper but am afraid if I
remove too much meat they won't fit well and will leak.

So I guess my question is, how tight should they fit before they
get flattened? Should they take serious pounding to get into their
seat, or should they go in fairly easily since the flattening is what
makes the seal?
 

[ollie gm]

The freeze plug should fit its seat without any excessive force. Most will just push in with your fingers. Don't forget to put your favorite gasket cement on the seat to prevent weeping and corrosion. Use a blunt punch and a hammer to flatten the plug to its proper tension.
 

[ZANE]

You may have the wrong size plugs????

I just put one in a 9N and it is 1-3/16". That is what all the N engines use.

Zane
 

[DON TX]

The ones I put in were too thick to just push in, I hit mine pretty hard with a ball peen and 1# sledge and they never did flatten. I was afraid to damage the block. They set well and haven't leaked and that's been several years now.
HTH
DON TX
 

[Bob Harvey]

Red RTV is a good product for this application. Use the 'ball' part of a ball pean hammer on the plug and whack the flat side of it with a 2#+ mallet-once should do it. You just need to 'dimple' the crown out of the dome. HTH
 

[ASEguy]

They should go in with the approximate force of shall I say a roofing nail. With the engine out, use either two hammers, one fitting just inside the lip of the freeze plug or an old socket to aid in installation. Use a non-hardening sealer such as RTV aroung the outside of the plug and set them flush with the edges of the block. Make sure you replace them all if one has corroded through or you'll be doing it again in another spot. Gerard
 

[kylemorley]

The plugs are 1-3/16" - Dorman 550-016

I just measured them - they are all about 1.193 (1-3/16" = 1.1875").

The hole in my 8n the plug goes in measures 1.183" - a bit undersized. So the total interference fit is about .010, no wonder the plug doesn't want to go in.

I'll probably grind or sand down the plug and hope the deformation when I flatten it will compensate for any irregularities in my sanding job (tractor is in the way, got to move it before snow).

Oh, if anyone has a NAPA or New Holland plug they can measure, I would be very interested in hearing how big it is.
 

[Hobo,NC]

[Hobo,NC]

ASEguy N plugs are a different animal
 

[Den N Ms]

Old welch plug post
Den N Ms

02-22-2009 15:16:24
74.226.66.123






Two weeks ago today on Sunday I hooked up my plow to my 8N worker to get it ready to plow up my garden.Got the plow hooked up then noticed a welch plug in front of the oil filter was leaking antifreeze.So I drove it to the shop and drained the block,removed the rusted through welch plug.Thinking I had an extra around in the tool boxes or some place from a rebuild.I Cant find the plug no place.I knew auto zone or Orileys would not have one,and NAPA was not open 1 3/16",NAPA # 219-1021 .Went in the house to look for it in a drawer,nope but spied a Kennedy half dollar hum took it out to the shop and checked it with the dial callipers,Just a hair over 1 3/16",outer edge smooth (no notches).Layed it on a big socket and concaved it with a ball pien and a hammer.Wiped out the hole and applied a little permatex put it in place with Johns face lookin at me and put the ball pien right on his nose and hit it with a hammer.Fixed and that copper 50 cent should out last the tractor and me ,wont rust any more.If I remember correctly Dorman welch plugs cost .49 cents.The next rebuild will have 1.50 in it to!
 

[Chuck (CA)]

First thought would be to put the freeze plugs in the freezer overnight, then the next morning, heat the holes with a torch, with the plugs covered in ice sitting next to the block.
 

[Angus Thom]

I agree w/ Ollie . . . should just press in w/ fingers.
Guess I was lucky when I did mine this year - see post on Wed Aug 08, 2012 8:40 pm subject: 8N Freeze Plug.
Also - there's lots of info on Utube - some good and some not so.
 

[ASEguy]

Well Hobo, I suppose I spoke too soon. I went out to see mine and I didn't see the usual lip. Gotta watch crossing the automotive/tractor barrier more closely. Gerard
 

[Hobo,NC]