Technical Weird Freeze Plug Failure

I live in Michigan & always use anti-freeze summer & winter.

 

Follow up on the freeze plug situation.

I talked with the owner of the car and he states the numbers matching 327/300 engine was rebuilt. Now he is beginning to questions how good of a job was done on the rebuild.

The serial number and Suffix codes are barley legible but are readable, probably due to it being lightly decked.
Serial number matches car and transmission and Suffix code comes out to be a 65 327/300, block cast in L84
With the low 4000s serial number of the car, and a December 1964 cast block, I believe this is the original engine.

The owner of the car states that the coolant has been replaced 2 times after the initial installation of the engine. There has never been any kind of water treatment/stop leak added to the system. That's roughly every couple years or so.
He used Prestone full strength green anti freeze mixed 50/50 with Chicago tap water all 3 times.
(maybe the Chicago tap water could possibly be a clue?)

The radiator was a new aluminum one and also a new heater core during the restoration.

He also did a large amount of the restoration of the car himself. He is also quite knowledgeable about all aspects of the car, so I don't have any reason to not believe what he says.

The reason the car came to my shop was due to a poor rebuild job by someone else, on the Muncie 4 speed.
We just happened to notice the very slight coolant leak from the freeze plug while pulling the transmission from the car.

He also said the freeze plugs looked new after it was rebuilt and that he painted and installed the engine himself.

In our shop we only use distilled water with coolant, so I am not sure about the Chicago City water. With all the crap they put in city water, who knows? We will probably never know what really caused this.

All we can do, short of complete tear down of the engine is, to flush out the water jackets the best we can to get out as much silt and scale as possible and reinstall brass freeze plugs and reinstall the engine.

Thanks for the input guys

 

On average, it is every couple years or so. Or it could be two times in the first two years, then ten years with the same coolant. No way to know.

but it sounds like you have the right plan to fix it.

I'd be tempted to pull the intake and see if the gaskets and sealing surfaces are still OK

 

If you think tap water might have had an effect, just think about what it does inside and outside of a human body! No wonder so many cancers around.....

 

With that info, I'll double down on the earlier guess of one of the acidic silicone goos being used on the plated plugs. If you look at the link in my earlier posts, it specifically mentioned the acid being released during cure attacks zinc. And the description of the 'stuff' on the plugs matches what I'd expect from something like a bathroom caulk.

 

I was poking around online and found out there are stainless steel plugs available.
(Notice how I avoided the "freeze" nomenclature? )

I'm also copy/pasting this off-topic but related opinion I thought was interesting.......
".......brass will not rust out but most hear that they won't hold in the block tight, leak or pop out. Proper installation is the answer. Most guy's use the easy method by inserting a socket into the center cup and then pounding it in. This method pulls the sides of the cup in reducing wall tension needed to hold the freeze plug in. Proper way is smear some sealant around the outer freeze plug and tap the outer rim to insert it flush with the block. There might even be a proper tool."
Hey! It's on the 'nets' so it must be true, right?

 

My city's water department has online information showing the chemical analysis of the tap water. There is listed total dissolved solids (calcium, magnesium), nitrates, chlorides etc.
This information is important to decide if the water is suitable for use in various industrial water systems.
Perhaps Chicago also posts such information.

Usually the problem with tap water is excessive "hardness" or dissolved calcium and magnesium, that will come out of solution and deposit scale on surfaces. However this scale is not corrosive.

It's hard to imagine anything in the tap water that would be acidic or corrosive in nature.

 

I think the sealer might be Permatex #1.....hard and brownish and I've heard of people using it on core plugs.

 

IIRC they are "Welch plugs"...but people just look at you weird if you use any term but "freeze plugs"

 

'core plug' is accurate also. 'Cause they were used to remove casting cores. But, I ask for freeze plugs at the counter like everyone else.

 

I like the brass plugs anyway, they look good on a black block. I have seen that before, on a used truck we purchased. Never got it all out of that one, It just kept coming out of the block. We got it to run cool, new radiator, hoses, heater core and flush, and flush and flush. Still it was nasty. Traded it away for another POS.

 

Well take a look at where the freeze plugs were made Dorman freeze plugs are Chinese mine started seeping in my 56 buick after a couple years. Just sayin

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