Ouch, I have that same rad. I'm worried now...

That just sucks.

It can't hurt to call Auto City can it? You never know, maybe you just got a bad one?

I would have done exactly that in car Pete. 

Again, I got in trouble by ASSUMING it would be fine if I drained it. I never do well by assuming.

Sounds like galvanic corrosion. With aluminum and steel (or brass or copper) in contact with the water, the dissimilar metals create was is essentially a battery. The aluminum becomes the anode, and the other metal becomes the cathode. Metal moves from anode to the cathode (have you heard the term sacrificial anode?).

The antifreeze contains corrosion inhibitors to prevent this from happening.

As an aside, the brass in the old radiators would actually become the cathode and the steel, acts as the anode...

ASSUME is a bad word.  When you assume, it usually makes an ASS of U and ME.

-- Edited by 66 Beau on Wednesday 9th of September 2020 08:00:29 PM

Thanks for the warning; I also have that radiator. 

cdnpont wrote:

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New.

I think it was an Auto City Classic. 

It sat for perhaps a year or so. Maybe it had a lot to do with being bolted directly to a steel engine stand. Dissimilar metals/water= corrosion?

 

Shame, it was a nice looking rad. The replacement will be a cheaper square top. and with a drivers side inlet. This 59-65 style rad really wasn't sized to work with my 67 rad spacer. Too tall and wide. But I was going for the 65 look.

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Typically you would expect the pinholes to occur at the contact point with the dissimilar metals, i.e. at the site where the electron transfer takes place.

Almost looks as though there were iron or other dissimilar metal filings settled in the bottom tank, and if it remained wet for a long period, this type of reaction would occur at that location.  There must have been some metallic content that was transferred over from your engine when you were running it?  Either that or some kind of contamination from when the rad was manufactured?

Good thinking and theory Mark. Perhaps the system brought down some iron fines from the block, heads or intake.

After a thorough cleaning, the heads had the ports cleaned up a little by my cousin. Maybe some fines made it into the cooling passages.

I did blow them out when I got them home, but perhaps some significant amount was still trapped. 

 

Regardless, had I used even a 20/80 mix I probably would have been fine. Even had I took the rad off and tilted it to complexly drain it, I would have been good. The drain cock open leaves about 1/2" of liquid when the tank is level.

Tap water Clint.

 

pontiax wrote:

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My Aluminium rad from Griffin came with instructions, distilled water and 50% antifreeze.

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 x2 !! Also once rad is mounted in car, stick a volt meter probe in coolant. Electrolysis like a boat!I run a ground if rubber mounted,,also may need to ground heater cores.What happens is current runs through coolant to get to ground.

-- Edited by hawkeye5766 on Friday 11th of September 2020 01:18:59 AM