freeze plug (core plug) installation and problems

Thought this may be worth sharing.
I recently had a customers 455 engine that I had built in 2012 blow out a freeze plug. There may be several reasons or no reason other than S#^? happens.
My normal way of putting them in, is with a sealer and driven in past flush with the top of the plug nearly or at the bottom of the bevel in the hole.
As you can see if you drive the plug in flush with the top of the block, you do not get a full contact on the side of the plug.
Searching on the internet and talking with Dorman and Pioneer there are several procedures some contradict each other.
My thoughts are that if you don't use a sealer as some recommend, you quite possibly could have a leak especially if the wall of the block was scratched when taking out the old plugs. I talked with one of the guys at Henkel (Loctite) and they have numerous sealants for applications like this but simply put permanent red Loctite from any auto store will suffice.
As far as the installation procedure there are also several thoughts, again Dorman and Pioneer agree that using an installation tool that is close to being the I.D. of the plug is the way to drive them in.
One other thought is that a plug is better off being driven in a little too far than not enough because it is then like cork in a wine bottle, the part that is in too far tends to expand which will help keep it from pushing out.
I have attached a picture that should explain installation depths.

 

"Red" Loctite, Anaerobic gasket maker, JB Weld/epoxy, Indian Head shellac, Copper Coat...Any of them will work fine as a sealer. I've used epoxy on most of mine for several years. I coat the back side of steel core plugs with epoxy, too--what the coolant can't reach, the coolant can't corrode. I don't know how successful that is--I don't let my coolant go acidic.

There was a time that I thought the "correct" way to pop a core plug into place was by applying force to the raised lip, rather than applying the force to the bottom of the plug at the ID. Of course, applying force at the bottom of the plug away from the ID is always bad.

I e-mailed Dorman about how they recommended to install a core plug, and never heard from them. I didn't type it in Chinese, so they probably couldn't read the e-mail.

 

I have always used #2 permatex. Even on non-blind holes. Seems to have worked.
Hello Mike hope things are going well.
Thanks Rick

 

We used loctite in a very high volume shop, then pressure tested every piece 100%.
We would shoot some proprietary sealing fluid into the casting in the rare case of leakers, maybe 3-4 per week(?), not exclusive to core plugs, etc..
150+ castings a day, for decades. Never heard of failures.
Warranty including paying for the entire repair if our casting failed, some of the equipment repairs would have been in the tens of thousands+.
Great info on sealing area!

 

My sealent of choice was "Aviation Sealer" but now it is 3M weather strip adhesive. Loctite makes several different "Glues" as I call them. Don't use the "Green" colored one, it will seal alright and you'll never get it out either without a lot of heat.