Freeze plugs

[Rick C]

A buddy of mine recentlt reinstalled a rebuilt 230 in his M37. During break-in run and a short road trip, freeze plugs have fallen out. His sources tell him it happens but seems a bit odd to me. any suggestions???

[m37jarhead]

THEY FELL OUT? Holy-moly!

When properly installed, freeze plugs are a small chore to remove.
Were the new freeze plugs "dimpled" to make them expand in the
hole? Putting in new freeze plugs is a fairly simple proceedure.
Clean the hole, "slather" some PERMATX Aviation Form-A-Gasket
Liquid Sealant around the contact edges of the freeze plug,
stick it in the hole and stoutly "dimple" the plug with a round-nosed punch.
Wipe excess gasket sealant from around the hole and let dry.
The sealant does little to help retain the plug in the hole.
Rather, the sealant is useed to prevent seepage of coolant
around the outside edges of the plug.

The Permatex "Aviation" sealant is readily available at NAPA
and probably most other auto parts suppliers. A four ounce
container is Item #80019 and is almost a 100 year supply for
me. Be sure to get the "aviation" grade.
You might also do a "search" for "freeze plugs" on this site
for more info.
Good luck and let all of us on this forum know how you
made the fix.
JB

[Carter]

His sources tell him it happens but seems a bit odd to me. any suggestions???

Your buddy better find other "sources" if info, freeze plugs falling out is not common unless they were installed incorrectly or the engine sat in freezing temps filled W/ water only, saw that happen to an IH V8 once and it did not crack the block.

[Rick C]

I didn't make the repair... I just pulled the engine for him. I've put freeze plugs in before and never had an issue. He had one come out when he ran it after rebuild then another a couple minuts into a test ride. No idea how they were installed or if they used the permatex. Will take a look when i can get there.

[Carter]

Didn't think you did Rick, let us know what you find.

[MSeriesRebuild]

Only 1 reason for freeze plugs coming out; they were not installed correctly. The center must be depressed slightly to tighten or expand the plug in its bore. Silicone sealant works best when applied around a CLEAN bore at time of installation. We only use brass plugs in our engine blocks on all rebuilt engines, they don't rust through and leak in a few years as will mild steel plugs.

[Tanner]

And installed properly, core plugs won't fall out, either...

'Tanner'