Frost plug replacement

[Verse]

What types of frost plugs have you used to replace a failed one while the engine is in place? How well have they worked?

 

[The_Eagles’_Nest]

Use brass ones with Indian Head shellack.

 

[1970FuryConv]

I use brass freeze plugs only. These are 1 5/8 on 318 small block. Sand surface, apply Permatex 2 Form-A-Gasket Sealant, drive new freeze plug into place. Stopped the leaks for 4 years until I replaced the motor.

 

[rags]

put cheapie steel plugs in my '65. lasted about 2 years. redid them with the ones shown above.

 

[Big_John]

I've never used these, but I know guys use them in boat engine applications with great success. If you can't get to it to hammer it in, this would be the way to go. I would use them.

Dorman product, buy by size and I wouldn't expect the chain parts stores to have them... In fact I couldn't buy even plain expansion plugs at the local O-Really's . No idea what I was even talking about.

 

[Mbaird]

Example…
Dorman 02483 Dorman Expansion Plugs | Summit Racing

 

[1970FuryConv]

I've never used these, but I know guys use them in boat engine applications with great success. If you can't get to it to hammer it in, this would be the way to go. I would use them.

Dorman product, buy by size and I wouldn't expect the chain parts stores to have them... In fact I couldn't buy even plain expansion plugs at the local O-Really's . No idea what I was even talking about.

View attachment 600458

Hi John. I used these and the leaks continued. Are the ones you pictured a special type of expansion plug? How tight should they be to get them to seal? Thanks.

 

[Big_John]

Hi John. I used these and the leaks continued. Are the ones you pictured a special type of expansion plug? How tight should they be to get them to seal? Thanks.
View attachment 600460

I've had a used car or two that had those rubber expansion plugs and didn't have an issue, but I figure those are really temporary fixes.

You put these in, hold with one wrench and tighten with another. As long as everything is clean, they should work at least as well as a replacement plug, and much better than a rubber one.

The Dorman expansion plugs, on the other hand, are used by some of the marine engine builders for new engines. What I read was they stayed in place better in a boat where the water is brought in from intakes at speed. Like I said, I've never used them, but I've held a couple in my hand and they look robust and well made. I think someone here may have used them with good results.

 

[CBODY67]

For ages, we used just the plain steel cup plugs as replacements. KEY to clean the sealing surfaces in the block, well! #2 Permatex was the sealer of choice, back then as now. Didn't even know that you could get brass plugs, back then, either.

There were some slightly curved plugs, too. Put them in place, with the curve outward, then hit them with a punch, in the middle, to flatten them out and seal, it was claimed. BTAIM

Main thing is to reliably seal the hole . . . once!

CBODY67

 

[73Coupe]

....... In fact I couldn't buy even plain expansion plugs at the local O-Really's . No idea what I was even talking about.

Dang...

For ages, we used just the plain steel cup plugs as replacements. KEY to clean the sealing surfaces in the block, well! #2 Permatex was the sealer of choice, back then as now. Didn't even know that you could get brass plugs, back then, either.

There were some slightly curved plugs, too. Put them in place, with the curve outward, then hit them with a punch, in the middle, to flatten them out and seal, it was claimed. BTAIM

Main thing is to reliably seal the hole . . . once!

CBODY67

The disc style plugs were used on the flat head 6s. Also available in brass.... they work well.

 

[DusterKid]

I only ever used Brass ones. I prefer the deep ones if I have them on hand. Steel ones will rust and need replaced, where brass won't.