Freeze plugs

[Campton1941]

1941 Plymouth PT 125. Today the front top freeze plug popped out losing all the fluid. The engine was overhauled last year and has only a few hours at idle on it.  I purchased a new 1 5/8 disc at NAPA.  It seems too small for the hole.  It goes in without any force. The new disc also seems thinner than the one that came out. Do they make and oversize freeze plug?  Anybody have an idea?

[Young Ed]

Just now, Campton1941 said:

1941 Plymouth PT 125. Today the front top freeze plug popped out losing all the fluid. The engine was overhauled last year and has only a few hours at idle on it.  I purchased a new 1 5/8 disc at NAPA.  It seems too small for the hole.  It goes in without any force. The new disc also seems thinner than the one that came out. Do they make and oversize freeze plug?  Anybody have an idea?

How much space is there? The idea is to compress the dome and which makes it expand in the hole to be a tight seal. 

[Campton1941]

I don't know how much space there is.  It went in  very easy.  I have not tried to dimple it yet.  I thought they had to be forced in.

[NiftyFifty]

http://m.oreillyauto.com/h5/r/www.oreillyauto.com/site/c/search/Expansion!s!Freeze+Plug+-+Universal/N0290/C0142.oap

 

in a tough spot you could get by with these, but not a permanent fix

[Campton1941]

Thanks for the link.  I have dimpled the replaced one.  I will let it set overnight before refilling the block.  Will keep my fingers crossed.

[Young Ed]

6 minutes ago, Campton1941 said:

Thanks for the link.  I have dimpled the replaced one.  I will let it set overnight before refilling the block.  Will keep my fingers crossed.

Did it feel like it tightened up? I would refill with water at first and try it for a bit. 

[Campton1941]

It feels tight, I cannot move it now. I may as well fill the block now, instead of putting it off and dreading the results.

[Young Ed]

2 minutes ago, Campton1941 said:

It feels tight, I cannot move it now. I may as well fill the block now, instead of putting it off and dreading the results.

I just suggested water because its cheaper to replace if you end up leaking!

[Campton1941]

Filled the radiator, started the engine, and the plug stayed in place and did not leak.  Beginners luck I would say.

[ggdad1951]

45 minutes ago, Campton1941 said:

Thanks for the link.  I have dimpled the replaced one.  I will let it set overnight before refilling the block.  Will keep my fingers crossed.

I'd properly dimple ALL of them....

[rekbender]

Hope your leak is fixed. I attempted to use Dorman steel concave plug #550-023 this winter on a '50 Dodge engine this winter. Some were .015" oversize (1.6240") and almost impossible to start. Pressure testing the long block at with air and soap suds at 20 psi showed tiny leaks around 3 plugs and I could not get them to seal. The block had been professionally cleaned but some of the cavities weren't perfectly smooth any longer. I removed the steel plugs and ordered Dorman brass concave plug #560-023. They consistently measured 1.632" to 1.635"  went in with snugly with no problems. I will not use steel plugs again. The brass plugs are nice and thick, and deform more easily. Just my 2¢.

 

[Dodgeb4ya]

Clean the core plug recess super clean and use JB Quik in the recess and carefully wipe a nice clean bevel around the properly completely installed core plg.... brass and you will have no leaks.

I do them that way on all shallow soft plug old Hemi's and flatheads. never a leak. And no blow outs either.

[Campton1941]

Good information to have and keep.  I will put this in my maintenance folder for future info. Thanks

[Matt Wilson]

8 hours ago, Campton1941 said:

1941 Plymouth PT 125. Today the front top freeze plug popped out losing all the fluid. The engine was overhauled last year and has only a few hours at idle on it.  I purchased a new 1 5/8 disc at NAPA.  It seems too small for the hole.  It goes in without any force. The new disc also seems thinner than the one that came out. Do they make and oversize freeze plug?  Anybody have an idea?

This happened with my 230 many years ago.  My machinist had installed the freeze plugs, but either didn't dimple them at all, or very little.  I lost all of my coolant on my way to work, and didn't know it till the temperature gage started rising quite a bit, and that means the temperature was WAY up there, since the gage was not in contact with any liquid and was only registering anything because of conduction of heat from the now-very hot surrounding metal.  It ended up causing a crack in the head, so I had to replace that.  I also took apart the rest of the engine and replaced a few other things to be on the safe side.

8 hours ago, 4mula-dlx said:

http://m.oreillyauto.com/h5/r/www.oreillyauto.com/site/c/search/Expansion!s!Freeze+Plug+-+Universal/N0290/C0142.oap

 

in a tough spot you could get by with these, but not a permanent fix

It turns out that all of the plugs on the left side of the engine were loose, and since I couldn't get to them very easily, I used these expansion plugs.  They seemed to work just fine, and I left them in there for several years.

[Dodgeb4ya]

On 5/18/2017 at 5:52 PM, Dodgeb4ya said:

Clean the core plug recess super clean and use JB Quik in the recess and carefully wipe a nice clean bevel around the properly completely installed core plg.... brass and you will have no leaks.

I do them that way on all shallow soft plug old Hemi's and flatheads. never a leak. And no blow outs either.

That brass plug has been fully expanded into the core hole recess with a large diameter driver with JB applied before and after the brass plug installation.

[Steve45hd]

From Moparts.com  thoughts? Frequently we are asked if we can supply these plugs in brass. The answer is NO. Because the engine block is made of a ferrous metal (iron), everything in contact with the iron block and the coolant water should also be made of an iron-based metal. If you remember your high school chemistry class, you learned that if you immerse two dis-similar metals (iron and brass) in an electrolyte (the coolant water), you will have created a galvanic battery cell that will rapidly erode the least "noble" metal part (your engine bock). You don't want that! Making sure that any metal parts used in the cooling passages are made of a ferrous (iron-based) metal will keep the erosion to a minimum. There are mechanics that will try to install brass core plugs into yo

[Dodgeb4ya]

Jesus...been thru this way too many times here.

Moparts is full of sh*t in regards to the use of brass in iron engine blocks and use of brass core plugs.

Period.

[kencombs]

1 hour ago, Dodgeb4ya said:

Jesus...been thru this way too many times here.

Moparts is full of sh*t in regards to the use of brass in iron engine blocks and use of brass core plugs.

Period.

Amen!   How many 230s have you seen in forklifts, 251s in combines etc.   I think every industrial I've seen had brass.

[Matt Wilson]

On 2/1/2024 at 6:56 PM, Steve45hd said:

From Moparts.com  thoughts? Frequently we are asked if we can supply these plugs in brass. The answer is NO. Because the engine block is made of a ferrous metal (iron), everything in contact with the iron block and the coolant water should also be made of an iron-based metal. If you remember your high school chemistry class, you learned that if you immerse two dis-similar metals (iron and brass) in an electrolyte (the coolant water), you will have created a galvanic battery cell that will rapidly erode the least "noble" metal part (your engine bock). You don't want that! Making sure that any metal parts used in the cooling passages are made of a ferrous (iron-based) metal will keep the erosion to a minimum. There are mechanics that will try to install brass core plugs into yo

The brass coolant distribution tube I bought off eBay a few years ago was advertised as NOS.  If it came with any factory packaging, I don't have it any longer, and I don't see any factory markings on the tube itself, but it certainly looks like it's been sitting on a shelf for 70 years, and I don't know of any aftermarket manufacturers who have made them out of brass.  So I think it is almost certainly an OEM piece, and if there was any issue with galvanic corrosion, Chrysler corporation would not have used or sold such pieces.  Every time I've read about anyone who has experience with brass tubes, they indicate that the brass ones don't rust, even after many decades in an engine block.  Definitely cannot say that about the steel ones.  Same goes for the brass vs. steel core plugs (freeze plugs), so I bought some of those as well and will use them whenever I get around to completing my flathead engine build.