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Radiator Stop Leak Additive

Ron H

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I was going to add to my earlier post about the concerning black slime in my radiator after a costly complete engine rebuild but my alert box has been emptied unbeknown to me; so a new post here. A fellow member said it was stop leak additive. And it is! And thanks to all who replied to that post it was very helpful! Now I got another new slant from an old mechanic: He said Chrysler used a stop-leak coolant additive in their newly built cars for decades! He said this was done as the castings Chrysler had by their spec were more porous than GM or Ford. Interesting as when I was at the engine shop a few months ago looking at my stripped/boiled block the mechanic said notice the color of the casting and had me look at a Chevy 327 block nearby. A truly noticeable difference in color. If I recall he said Mopar included an alloy maybe nickel if I remember, that the others didn't use. Fact or fiction? Anyone know anything about this?
Thanks!
 
I know 70 AAR/TA 340 blocks and Hemi blocks had a higher nickel content then non performance blocks. Some of the other Mfgs also had higher content in their high performance type blocks also.
 
I was going to add to my earlier post about the concerning black slime in my radiator after a costly complete engine rebuild but my alert box has been emptied unbeknown to me; so a new post here. A fellow member said it was stop leak additive. And it is! And thanks to all who replied to that post it was very helpful! Now I got another new slant from an old mechanic: He said Chrysler used a stop-leak coolant additive in their newly built cars for decades! He said this was done as the castings Chrysler had by their spec were more porous than GM or Ford. Interesting as when I was at the engine shop a few months ago looking at my stripped/boiled block the mechanic said notice the color of the casting and had me look at a Chevy 327 block nearby. A truly noticeable difference in color. If I recall he said Mopar included an alloy maybe nickel if I remember, that the others didn't use. Fact or fiction? Anyone know anything about this?
Thanks!
Most MoPar truck blocks are hi nickel iron. It is stronger and has a slightly different color than regular gray cast iron.
 
GM still uses a mixture of crushed walnut shells (not kidding) and aluminum powder as a stop leak in many new motors during manufacturing. A GM 'customer campaign' back in the early 2000s for their intake gasket fiasco was to double dose the coolant system with their walnut shell stop leak mixture and hope the customer would trade off the car before the gaskets puked (I had a 2001 Impala and lived through that; first and last GM car for me).

An old timer (now deceased) neighbor of mine who had worked at an AMC plant in the 60s and 70s claimed all cars on the assembly line received Bars Leaks before the coolant was added.

Back in the late 1980s when I help rebuild a friends 455 Trans Am, the machine shop that did the heads gave us two bottles of Alum-A-Seal and said we should run it in the cooling system during break in.
 
Hmm...this gets more and more interesting! Here i thought I risked a member asking me if I believed Mr. Rogers wore his cardigan sweaters to cover up all his tatoos he had as a Navy Seal...
 
Alumaseal is MUCH less likely to gum up your thermostat than Barr's.

If I can put together a freshly tanked engine and cooling system and NOT need to use a sealer, I don't see why they factory would need to.
 
From the Bars Leaks web site:

Now Bar’s Leaks is factory installed in 3 out of 4 new cars made in USA by such as General Motors, Ford, and Chrysler, and Bar’s Leaks is the most widely used stop-leak and rust inhibitor in the world.

http://www.barsleaks.com.au/the-bars-leaks-story/
 
All the mechanics I've talked to and my brother (who was a mechanic years back knowing these guys ) some with years rebuilding several muscle car motors, now retired or I'd have tapped them, say they've NEVER put coolant additive in their rebuilds. Yet the shop that charged me premo for the rebuild too embarrassed to say what they charged, says "we always put in a little additive with our rebuilds". Not sure what's a little...looks like a lot in my car...
 
What a story line we got here huh? My brother recalled working at one of the dealerships he was with and the manager would toss in stop leak in POS cars they got on trade and shipped 'em to the auction. Said the manager did as mechanics couldn't as their work required a paper trail...
 
Based on what I've heard and thanks much to all replying here, I'm flushing the system and run it with pure water for a drive to reach op temp then flush that and put in new coolant or re-flush again if it's gunked up then add proper coolant. One thing I could say before the rebuild, and motor ran great, the cooling system was always very clean. Nice to have it that way again after multiple $$$$ in the rebuild. Seems like a reasonable expectation...
 
For years I was called crazy by motorheads at work, but my dad who was the neighborhood shade tree mechanic (day job as a machinist) used CASCADE power for radiator flushes. Two large cups of cascade powder, fill with a garden hose, idle with the heater on until the thermostat opens, drain, fill with water and idle again. Drain, and fill with coolant.

Dad's take was cascade would gently clean the system.

Then, last summer in Hot Rod magazine they had a F150 Lightning that the oil cooler had leaked into the cooling system. How did they clean the cooling system?

CASCADE!

Passed that article around the office. Seems dad was spot on on that home brew trick.
 
Glad you figured out the issue. So question is are you going with Cascade Lemon Scent or Fresh Scent, LOL!
 
From the Bars Leaks web site:

Now Bar’s Leaks is factory installed in 3 out of 4 new cars made in USA by such as General Motors, Ford, and Chrysler, and Bar’s Leaks is the most widely used stop-leak and rust inhibitor in the world.

http://www.barsleaks.com.au/the-bars-leaks-story/
I have two original Chrysler factory line pellets used in the late 60's.....

The guy who got them originally worked at the Ham plant and swiped many of them(along with other parts, lol) and carried them out in his lunch box....The guy I got them from said the line worker told him they were added to every car on the line....

I will post a pic of them later tonight
 
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Here are those original factory line stop.leak pellets....
IMG_20170606_192805961.jpg
IMG_20170606_192815852.jpg
 
I think they get somewhat a bad rap and blame for other cooling system issues. Put it in a Northstar V8 for years for reasons mentioned above. Did their job. Never a problem. Did get rid of the Dexcool for green. Won't pure water damage the water pump?
 
Deathcool was brutal and probably caused GMs bankruptcy. What a fiasco.

Those pellets look familiar. I think those are AlumASeal produced.
 
Deathcool was brutal and probably caused GMs bankruptcy. What a fiasco.

Those pellets look familiar. I think those are AlumASeal produced.
Bars still makes them but the shape is different ... that is how you can tell the difference...
 
I managed a Navistar(International Truck and Engine Corp) commercial truck dealership service department for 40 years and we always used Cascade to clean and flush out cooling systems after a oil cooler failure (Cat, Cummins, Detroit, International, etc.). Some times it would take up to 5 flushes with Cascade to get most the oil out. As far as Cascade cleaning a corroded system, not of much use there, not a strong enough cleaner and once the radiator core tubes clog shut from corrosion the cleaning cemicals can not get into them so radiator manual rodding out or replacement is the only solution.
 
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