Technical Which freeze plug is best?

I know that brass ones would not rust but I seem to recall someone saying before that steel is better and I don't remember why. Also, should some form of sealer like Permatex or similar be applied? It is for my 1972 Plymouth 318 engine. Thanks for any info.
John

 

Brass

 

Brass if you can find them,,forget the sealer. HRP

 

Some say that brass expands at a different rate than iron so are more likely to pop out. Haven't seen it happen personally though. I always use Permatex on my freeze plugs. You can coat the inside to prevent rust, but with a properly maintained cooling system that should not be an issue.

Next topic: the difference between core plugs and freeze/expansion plugs.

 

Brass is much better lasts forever unlike steel thats rusts away even when coated.

 

I built a couple inthe 1980's that when I put the frostplugs in I used indianhead shellac on the backs of them , no rust thru yet . and one of the motors is run with straight water . I like brass as it forms to the hole better if its old and rusted , but had good luck with steel units too .

 

I am sorry that I can be of no assistance to you

 

I like the cup style brass ones with permatex #2. If the block hasnt been tanked and the holes are dirty/rusty you will need to clean them up with a small brass wire wheel on a drill or preferably an air grinder. Core plugs and #2 wont hold in a dirty.rusty hole.

 

That's funny,and a name like freeze plug! HRP

 

Steel, and use sealer.

And the strange thing is, we both are right.

 

I've worked in the marine business for years so I always use brass ones. Most machine shops can get them for you, maybe even NAPA and other auto parts stores too.

I also coat the mating surfaces with Permatex.

Don

 

Brass plugs are great if you don't maintain your engine.

 

Has anyone used the new expanding rubber plugs? I used them in an old jeep where access was an issue. They also worked nicely for plugging up valve cover holes.

 

I have used expando plugs where a rotted out soft plug was in a hard to reach area and pulling tghe engine was out of the question. I would not use expando plugs in an engine that was out of the vehicle.

I like brass but I don't think that they are any better then steel.

 

Agreed. Expando rubber plugs are just for a quick fix, not long-term. And they are certainly nothing new.

There is a technique to removing steel & brass plugs. Cannot remember how many engines I have built where someone just punched them all the way in and installed a new one. Can you say blocked coolant passage?

 

We always used the brass ones on boat engines, steel on cars. NAPA or whoever carries both. I did use an expandable behind a motor mount once, too cold to lift the engine at the time, and it was in there for years.

Bob

 

i was able to find BOTH sizes that my plymouth engine calls for in brass, and on the shelf at a napa store.
the brass is more forgiving and will work better for an engine that wasn't all cleaned up properly.

 

As Squirrel inferred, system maintenance makes either one work well and last a life time.