Freeze Plug Choices

[Bingster]

I just read a very old post from Don Coatney where he shows various designs of freeze plugs. For my '47 Desoto, it seems that I use a 1 5/8 brass plug.  Question is, some are dish-shaped and others like a cup. And, Napa?  Dorman seems to be a common brand.

[Sniper]

Disc, the way the holes are machines a cupped one won't work properly.

Edited October 14, 2023 by Sniper

[Los_Control]

Ours are the dish shaped 1-5/8"  .... Proper name is a Welsh plug.

 

I have heard good and bad about brass. Brass will not rust .... leaving the block as the weak point.

Others have claimed that brass will cause the block where the plugs seat to get divots and rust and make it hard for a plug to seal.

This could easily be a old wives tale .... I dunno .... but the steel ones have lasted 70 years .... good enough for me.

 

Just remember when you install them to clean the seating surface well, some apply a little silicone, I did not.

When you look at your installed plug the dish is inside the block.

When you install the new, the dish is outside the block .... then you smack it with a hammer and the dish is now inside the block.

This makes the diameter of the plug expand and seals it to the block .... Ask me how I know.

 

Also I have brass plugs, just because thats what the autoparts store had ... I would be fine with steel.

[soth122003]

30 minutes ago, Los_Control said:

but the steel ones have lasted 70 years .... good enough for me.

That was my thought as well. I used the steel plug. Clean the area good and use a light coat of sealant as these cars are a zero pressure coolant system (most anyway) you don't have to worry about a blowout of the plug. 

 

Joe Lee

[Los_Control]

1 hour ago, Bingster said:

it seems that I use a 1 5/8 brass plug.

@soth122003 It was that statement .....Did they ever come from the factory with brass plugs? .... Maybe some did.

Mine were steel when I pulled them. ..... I'm thinking brass is more of a marine application that many adopted over to automotive use?

 

Either way, I installed brass plugs backwards back in 2018 and they do not leak.

Was just this year I installed a aluminum radiator with a pressure cap .... I'm expecting it and I have a new set of steel plugs sitting on the bench waiting to be installed properly.

 

 

[Matt Wilson]

8 hours ago, Los_Control said:

Did they ever come from the factory with brass plugs? .... Maybe some did.

I don't know if they ever came with brass plugs, but I purchased a NOS brass coolant distribution tube online, and have read that some came from the factory with brass distribution tubes, so it would not surprise me if some also came with brass plugs.  If Chrysler fitted some engines with brass tubes, then it seems that they must not be detrimental to the iron block, and I would therefore think the brass plugs would not be either.

[andyd]

In 54 years of playing with mopars I ALWAYS use brass welsh plugs........I have never heard of any detrimental problems using brass plugs..........they cost a littler more I suppose than steel plugs but once installed they never rust and as far as reacting with the cast iron I have never heard of that and would think its codswallop.........but use whatever you feel comfortable with.......andyd

[Dodgeb4ya]

Brass plugs are used in all MoPar flat head marine applications.

Chrysler straight eight engines front and rear non accessable block core plugs are brass from the factory.

Silly wives tales as to flatheads having corrosion issues using brass.

Shown are a couple Ply/Chrysler original car engines with rear and front of block brass plugs..

A reason MoPar used brass...

Edited October 16, 2023 by Dodgeb4ya
Added pics

[Bingster]

I read P14B on that plug.  Is that a Dorman number?

[Sam Buchanan]

16 minutes ago, Bingster said:

I read P14B on that plug.  Is that a Dorman number?

 

It only took Mr. Google 3 milliseconds to answer that question:

 

https://www.summitracing.com/parts/mel-mep-14b

 

[Bingster]

Yeah, I know. I found it.

[SteveR]

In looking at Brass and Cast Iron there is a galvanic reaction between the two. There is also a galvanic reaction between steel and cast iron but it is lower than brass. I guess I look at how long the steel freeze plugs have been in the engines and figure it will outlast me if I use steel. I don't think it makes much difference between brass and steel. I am replacing mine with steel because that is what was available. My engine is a 1950-51 230 cu in and as far as I can tell these plugs have never been changed.

[desoto1939]

A lot of you have been talking about the reaction of Brass Welsh plugs against the cast iron block and or the use or brass distribution tubes.

 

But we all use brass thermostats in the top of engine heads and this is sitting in the cast iron head and the cast section of the outlet and return to the brass radiarot.

 

So i guess just from this point of view then our engine should have leaked and been destroyed because of the brass and cast iron reaction chemical reations.

 

So my engine is original for my S6 39 Desoto with the brass thermostat and original radiator honey comb core.

 

Go figure. I guess pick what ever type of plug is available for your car or truck.

 

Rich Hartung

Desoto1939@aol.com

[Los_Control]

I think I may have been the first one to bring up the reaction talked about using brass plugs. .... Pointing out there are mixed feelings about them.

@Bingster mentioned that his engine uses Brass plugs .... I just wasn't convinced his engine came with brass plugs .... or that it was a requirement.

 

Anytime you have dissimilar metals there is a galvanic reaction. That is just normal.

I have brass plugs in mine now because that is what the local auto parts store had in stock .... I'm perfectly fine with using steel also .... either one will work just fine.

[capt den]

dorman makes a core plug that you put on with a wrench and a socket. part # 568-010. they are about $5 each at any parts store. you may have to order them, or look online. they are supposed to be temporary, but mine have been in my 265 block about 8 years. easy to install with the engine in the car. 

[Bingster]

My Napa store said there was only one Dorman 1 5/8 brass plug available in the country. Of course O'Reilly could get the P14B's but you have to buy ten, which I don't need at the moment.

[Dodgeb4ya]

Back in 2016 there was a core/soft and welch plug thread...

Yes the 1-5/8" brass plugs for the flatheads and Hemi's are kinda tough to easily find now days.

[Bingster]

I got the old freeze plug out pretty easy, and I just could not believe how much muddy slush came out of that hole. Not just around the perimeter of the hole, but on reaching back both sides and above and below the hole.

 

If you multiply that by the rest of the freeze plugs, I have to wonder what condition the engine is in. Anyway, I still cannot start the engine.

 

Should I just leave the freeze plug open for the winter or put a new one on? I don't think putting water in there would be a good idea.

[46BulldogDodge]

From the "While yur here" category....consider taking out all the others you can easily get to, followed by powerful jets of water from all directions into the holes in combination with wire picks/scrapers.  Like the dentist does with your teeth.  Leftover casting sand and rust sediment have accumulated for decades clogging up the cooling process.  This will be messy...but so worth it for the engine's next 50 years!  Regarding leaving it open over winter without water, that would be fine AS LONG AS YOU PREVENT RODENTS FROM GETTING IN THE OPEN HOLES. Best approach would be to install new welch (freeze) plugs and fill with correct water/antifreeze mixture before winter.  Prevents further corrosion and lubes the water pump.

[Bingster]

I think that's what I'll do. I tell ya, I've been wanting to start this car for the past three years but due to my work schedule it always boils down to October and this is the third October I bought a battery and didn't start the car.

 

I've come close this year, but for some reason the starter will not engage. It did a couple of weeks ago when we turned it over without plugs, but now it spins but does not crank. I spent a couple days trying to diagnose the problem, but have given up for now. Might be the solenoid.

 

I've also come to the conclusion that this engine - after seeing all the sludge in it - is going to have to be eventually rebuilt at least to some degree.  It's not realistic to believe that I can run it as it is.  And really, after watching dozens of engine rebuilding videos, I am very interested in giving it a try.  It's not all one big complicated piece of machinery.  I can break it down now in my head.  I'm hitting 70 New Years Eve, and my wife has dementia. I've been her caregiver for four years now.  This car has been a nice diversion from Caregiver Burnout.

 

So I don't know what the future has in store. If I end up alone then having the car might be a nice project. But I'm not really certain if the car will take on the same meaning, however, as it does now.  Who but God knows the future? I just leave it up to Him to call the shots.  He does it far better than I do.

 

Well, you just happened to be the one I'm getting off-topic with.  This board doesn't want to hear a lot of personal problems because all of us are looking to this site for a diversion one way or the other.   But I think I will divert my attention to the freeze plugs.  Thanks!

[SteveR]

I'll be 71 in March, my wife will be 69 in Nov. Our car came late in life when I was 65. We can not afford to go on vacations so we visit car shows. We have met some very nice people and call them friends. There is always a smile, a handshake, and a big welcome whenever we meet up.

 

I can't imagine what you are going through but it looks like you know God is on your side and that you can rely upon Him. That is in your favor.

 

I would finish your car and visit the car shows, make new friends, There is nothing like driving one of these old cars. It will, and will continue to put a smile on your face if nothing more than just going to the store as we so often do. Blessings to you, you are on my prayer list!

[Bingster]

Thanks so much Steve for your kind words.  And prayers! I'll do likewise for you and your wife. God Bless!

[Bingster]

Well, so I got the freeze plug out in back of the oil fuller tube, which so far does not want to unscrew, and I've noticed a small chunk of metal maybe an 1/2 inch long on the bottom at 6 o;clock has been chipped off. Most of the rim where the plug attaches is missing.  There is a small rim left, however. So how bad is this, and what can be done to remedy it. (Please don't say junk the engine.)

[DJ194950]

Pictures would really help for us to advise.

 

TKs.

 

DJ

[Bingster]

I'll do that Sunday.