SBF Guys: wax-like corrosion behind water pump

I'm changing out my water pump on my 53 F100.
'86 302 w the usual additions. Edelbrock Carb/manifold, small cam, headers.


I completely redid the cooling system last year. New Aluminum Radiator, New Water Pump(polished), Hoses, 180 Thermostat, Flushed the system. Everything worked great all year. This weekend the water pump bearing started singing some and I don't like to wait for a fan to take out the radiator so I ordered a new pump.

Took it down tonight, and noticed a white waxy corrosion buildup between the pump and the timing cover. Sorry now I didn't take a pic. For The record, the antifreeze is bright green with no signs of corrosion in the radiator.

The backing plate on the water pump is steel, the timing cover is aluminum.

Any ideas as to what causes this reaction? I've been dealing with sbfs for years and never saw this before.

Thanks for any ideas.
-Big George

 

Electralisis? (sp?)

 

Sounds more like some white lithium grease that might have been used to hold a gasket in place, or maybe some leftover manufacturing lubricant from inside the radiator. If it was a very small amount, I wouldn't read too much into it. Might even be calcium deposit, if you used city treated water, they use calcium to cause the dirt to sediment out of the water before they filter it and add chlorine and flouride. Just a couple possible causes.

 

It was enough for me to say wtf. I use prestone 100% and dilute it myself with distilled water only.
This stuff resembles that absorbant gel they use for diapers and liquid spill recovery booms.

 

I would say galvanic corrosion.
Here is what Wikipedia has to say on the subject.
Dissimilar metals and alloys have different electrode potentials and when two or more come into contact in an electrolyte a galvanic couple is set up. The potential difference between the dissimilar metals is the driving force for the accelerated attack on the anode member of the galvanic couple.
The electrolyte provides a means for ion migration whereby metallic ions can move from the anode to the cathode. This leads to the anodic metal corroding more quickly than it otherwise would; the corrosion of the cathodic metal is retarded even to the point of stopping. The presence of an electrolyte and a electronic conducting path between the metals is essential for galvanic corrosion to occur.

 

Apparently with use/time the corrosion inhibitors (silicates, phosphates) in the (green) EG are depleted. The EG ethylene glycol begins to break down into (5) organic acids. The most reactive metal in the system, aluminum, then becomes vulnerable. I'm speculating that the precipitant is the organic (oxalic, glycolic... salt of aluminum The bottom line is changing the coolant before the inhibitors are consumed .

 

^^^^^^
I'm gonna take yours and the others word for it. I figured it was something like that. I've seen the usual rust and calcium, but never this waxy stuff. I thought it was some additive from the coolant that gelled just wondering if they have new formulations that are doing damage like how this ethanol gas eats up fuel systems