Cool/Heat: Freeze Plugs

[tjanowia]

I had my 58 GH engine rebuilt about one year ago and instantly saw water seeping from all of my freeze plugs. I was told to put stop leak in it and problem stopped until last night while taking cruise on back roads of Michigan and noticed temp gauge rapidly rising. After $104 ride home I found that one of the freeze plugs had just fallen out. I imagine they were either wrong ones or installed wrong. I found a box of expansion plug 1 1/2" steel cup plugs in the garage that have about a 1/4" lip on them. Wondering if these are best to use on this, if the cup goes in or out and if permatex 2 is sufficient and any other helpful advice. Also thanks to the off duty Michigan State Trooper who stopped and found a tow truck for me in the middle of the night in the middle of nowhere. Thanks, Tim

[bezhawk]

No, the freeze plus, or core plugs are not the cup type on your 58 engine. They are a domed disc. You put the curved side out and hit them directly in the middle with a ball peen hammer to flatten the dome enough to wedge into the block. The curved side must face outward or hitting them will not expand them. I always use Indian Head red gasket shellac as a core plug sealant. Some people use JB Weld. Never use silicone as it prevents the edges from gripping tightly.

[studegary]

What Bez said.
I would suspect other work that that engine shop did. Are they also the ones that told you to put stop leak in? That is not a repair for a core plug.
I would suggest replacing all of the core plugs.

[tjanowia]

Are they 1 1/2" and are they available at any auto parts store. Thanks, Tim

[jbjr]

1 1/2 and yes any parts store will have them, when I did them on my 54 3r5 I had some room to work it might be tight on yours. I used permatex and there was no problem.

[CaffeineRacer]

Yeah Wow. Super shady engine shop. If you can't install freeze plug correctly you have no business being near any other part of an engine.

[Deaf Mute]

I used to carry one of those rubber expansion plugs with a washer on both sides and an adjusting nut in my tool box. (Please don't ask why.) Then I learned the correct way to install them.
But one of those plugs might be needed if you cannot swing a hammer at the installed engine block.

[Mike Van Veghten]

Just for sake of argument...

A "ball peen" is NOT the best way to expand these plugs...
While doing this work in the car is challenging enough, use something with a very large radius, almost flat, to hit the plug with will give the best results. And as you are hitting the plug, continue to go around in a circle to make the plug as "flat" as you can make it.
Do NOT just smack the center so that there is a "dimple" in the center, these plugs are designed to have the best expansion into the block when they are "flat".
I use a rod/shaft that's about 3/4" round x about 12" long (what I've used), as I said, a large radius ground on the end. It would be flat...but you normally can't get a straight hit onto the plug...hence the slight round shape.

So just remember, the flatter the core plug ends up, the better.

And yea, some sort of sealer can't hurt.

Mike