Core plug revisit

[Pentroof]

I guess it's just my turn. In the core plug discussion recently, I threw my method on the table for discussion, along with many others. Never had a leak, although I don't build engines for a living.

This weekend I fired up a 390 I just finished and it all went very well...until I noticed a small pool of coolant. Driver's side forward plug is weeping (my wife wants to know why it's so sad).

Installed the same as always with a thin wipe of gasket shellac on the plug as well as the bore, let tack up and then sent it home. I never press from the center of the plug, always the outside edge. Plugs are Dorman #565-036, brass 1 49/64". This one looks like its got a bit more cup to it, but could be an illusion provided by staring at it while on my head in the bay of my F100. Also may be driven in a touch too far?

I guess I'll clean it real well and the replacement will get some sleeve retainer like Blair suggested.

[Rory428]

I have always used Permatex or KW Copper Coat brush on sealer on the core plug holes in the block, no problems. But if you are actually hammering in the new plugs on the flanged edge, that could be your problem. I always use a 1/2" drive socket that is just slightly smaller than the recess of the core plug, and tap it into position. If you hammer on the flange , you could easily distort it, causing a leak.

[Pentroof]

Yes, we're on the same page. That's what I meant by outside edge. I use a large, deep socket that is slightly smaller than the inner diameter. Too large and the outer rim will actually tighten against it and you won't be able to get your socket back!