Here's an important tip for those choosing to use an aluminum rad for running up an engine on a stand.
Use coolant, Never straight water.
I used straight water. Drained it after testing the engine, but left it on the test stand hoses still connected.
The residual water left in the bottom tank caused pin hole corrosion. The bottom tank of my new rad is now full of holes.
I'd assumed that it was better to run water for a temporary run up, as it is far easier to deal with when draining and cleaning up. Thought a little bit left wouldn't be of concern. Big oops.
Perhaps if I had pulled the hoses it would have evaporated within a short period of time.
Live and learn.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
Pin holes that fast ! How long was the water in the tank. This just boggles my mind and i just do not get it. Was this rad bought new by you or an old rad you picked up.
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1957 Pontiac Pathfinder Deluxe sedan restored 261 six
1974 Chevrolet Caprice Estate wagon low mileage original 400 V-8
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.
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 Guys, I will call them and see what comes of it.
One thing about the rad is, although I have a 4 speed, it was for an automatic and has the integral cooler in the bottom tank. They didn't have a rad without the cooler.
And it appears that the cooler could actually be made of brass. At least the screw in fittings are. If it doesn't go back I'll cut it open and see.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
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.
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.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
My Aluminium rad from Griffin came with instructions, distilled water and 50% antifreeze.
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
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.
To me Mark...Looks like your rad is isolated. Rad hoses are an insulator so are engine mounts and trans mounts. On an engine stand you would need a ground strap from rad to block so that current does't go through coolant. This also happens in welding machines. They use tap water and it burns up their tig torch.......