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Discussion Starter · #1 ·
Original never rebuilt 62,000 mile engine. Freeze plug leaked so I removed it and found a ton of thick brown sludge in the cooling passages, nearly blocking them. Had to dig the sludge out with a screwdriver. 4 previous flushing had not touched it. Too thick, too well wedged into the nooks and crannies. Now I know why the car gets so hot on 90 degree days after an hour. Resticted water circulation! So...... short of removing the other freeze plugs and digging it out, has anyone else come up with a easier fix?
 

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I seem to recall someone here saying they removed a few freeze plugs and used high pressure water to clean the block. Something like a pressure washer.

Don
 

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The only way to be sure to get it clean short of a complete tear down is to knock out the freeze plugs on both sides of the block and the front two plugs under the heads. Then go at it with what ever you can to loosen it up. Then lots of flushing through the plug holes with a pressure washer, Multiple times. It is going to be very messy, There is no other way around it with the engine still in the car. :)
 

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Just thinking that this may be a factor for the guys that are struggling with their cooling problems.

I had my block flushed out on the rebuild.
 

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Good luck....but I'd go the safe way and tear it down & flush.....:anim_25:
Cowboy :flag6:

:gba:
bowtie-trifive
 

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Discussion Starter · #6 ·
What do the engine builders do to clean a block of the crud and sludge? Boil it out in a lye solution? There must be some way to circulate a mild acid or base solution in the engine block only bypassing the radiator? Using Something that would attack the sludge and dissolve it into solution. I suppose it would attack the gaskets as well so probably not feasible?
 

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I believe they hot tank the block before the build, at least I know the guy that did mine that is what was done and they magnafluxed it to check for cracks.
 

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Original never rebuilt 62,000 mile engine. Freeze plug leaked so I removed it and found a ton of thick brown sludge in the cooling passages, nearly blocking them. Had to dig the sludge out with a screwdriver. 4 previous flushing had not touched it. Too thick, too well wedged into the nooks and crannies. Now I know why the car gets so hot on 90 degree days after an hour. Resticted water circulation! So...... short of removing the other freeze plugs and digging it out, has anyone else come up with a easier fix?

If one core plug was leaking you have more leaking soon. If the engine is in the car and running good. Go ahead knock the core plugs out of both sides of the block and wash the crude out.
:anim_25:
 

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Discussion Starter · #9 ·
I may just do that, just remove the freeze plugs and clean the block by hand. Literally by hand because it is like modeling clay, very thick, and very well stuck to the metal. I have to dig at with a screwdriver to get chunks out. I do not see anyway to get at it with a pressure washer nozzle in those tight quarters. Man would that ever make a mess anyway! I think the hand removal will help enough to actually cure the problem which only happens after an hour on 90 degree days. 70 degree day is fine.
 

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What do the engine builders do to clean a block of the crud and sludge? Boil it out in a lye solution?
The traditional hot tank in what was basically a lye solution has pretty much been outlawed by the EPA. Nobody uses it any more. But that's been replaced by an even higher temperature process that gets the block clean, including the water passages.

If all your freeze plugs are rusting, I think that you aren't going to make a lot of progress with "in the car" solutions. But think about this, the heat is generated in the cylinder heads and at the top of the block. Even if the bottom of the block is full of crud, this isn't a real problem.

Evidence of this is the guys that fill the bottom of the block with cement or other filler.
 

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Hate to say it, but..... what you see on one plug you'll probably see in the rest of the engine. I thought replacing the freeze plugs *might* be a good idea, but getting to them with the engine in place would be a PITA, so I vowed to get around to it "someday".

86K miles., sitting for 45 years, got it running for about 8 minutes, then found some other problems that meant I had to pull the motor. So.... I found this when I had to pull the bell housing.



Uh-oh. Well, Someday had arrived. With the engine removed I figured now was the time. First plug:



Line up of all the suspects:



Grabbed a hose, turned it on full blast, and wore the oldest, dirtiest clothes I had. Shoved the hose into every opening from every angle I could manage, then used a pressure washer to repeat the process. You wouldn't believe the amount of gunk that came out of that engine. After 20 or so minutes, the water didn't have any more "chunks" in it.



This does not show the hundreds of small lumps of stuff the water forced out of the engine, nor the color of the water with grime in solution. Make sure you have a place for the water to drain that is safe, and can clean up the mess.


Seems the best I could do without a full tear-down and commercial boil-out.

PS.... if you do this, might as well pull the radiator, turn it upside down, and back-flush it as well.
 

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What do the engine builders do to clean a block of the crud and sludge? Boil it out in a lye solution? There must be some way to circulate a mild acid or base solution in the engine block only bypassing the radiator? Using Something that would attack the sludge and dissolve it into solution. I suppose it would attack the gaskets as well so probably not feasible?
years back my late father owned a radiator shop here in Phoenix, and often he would do a block flush when he replaced a radiator core. He would remove the thermostate and housing and Install a housing that he affixed to a Hose that transitioned to a garden house. He then attached a real long flex hose to the water pump and let the water run for quite some time. If he didn't see an increase in the amount of water coming out of the block or if his upper hose began to leak he would add vinegar to the block, after plugging the bottom hose and let it sit over night at the most.he never used chemicals, he would always say " How does the chemical know when to stop" and and the following day he would run the hose again. Once he was happy with either the flow or water color he would replace themostate and either remove and clean or replace the waterpump altogether. Doing it this way kept the customers car clean and didn't jeopardize the internals.

I would try the block flush after you install the freeze plugs, I would flush the radiator as well...park the car on the grass and see what happens. Doing it this way wount harm anything and wont make a mess either.
 

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Discussion Starter · #14 ·
Vinegar is a weak acid. Great idea! 50% vinegar and water works great to removed deposits in household plumbing. So why not in the car? On my car the heads were removed and boiled out, they are clean inside. So is the aluminum manifold. My only thought is if I have to pull the engine, I would just as soon put a mild 383 crate engine in there, disguised as a stock 270 hp.
 

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Isn't vinegar a chemical?
Why stop there ?...what about the water aswell since water's electron configuration- it's valence shell makes it by definition of the term "chemical" a chemical.

CJ I'd say give it a shot, but if cooling is the only problem why not change to a corvette fan blade and a fan shroud?
 

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Discussion Starter · #16 ·
Well I don't thing more airflow or bigger radiator will help the problem. The block is nearly plugged up with sludge so the water cannot get through. So I can put huge cooling system in there but it won't really help that water move. That one freeze plug clean out did seem to help!
 
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