Powdery substance around water pump?

[MTribe]

Anyone know what this is? It's a very light powder, comes loose with the slightest touch. Maybe 2000 miles on a full engine rebuild, new hoses, etc. Thanks for any input!

 

[mgedit]

Looks to me like water pump leak, either internal seal or at gasket. Cheers, Mike

 

[PKPoole]

This looks a lot like galvanic corrosion residue which usually occurs from dissimilar metals and a weak current flowing across the material. Is it possible you have a weak engine ground and somehow you are getting an electrical flow across the parts?

 

[MTribe]

Ah, very interesting. Problem is there is nothing really connected to the water pump that would conduct current... though I think there's a water temperature sensor right around there. Is the idea to make sure no current is flowing from one part to the other?

This looks a lot like galvanic corrosion residue which usually occurs from dissimilar metals and a weak current flowing across the material. Is it possible you have a weak engine ground and somehow you are getting an electrical flow across the parts?

 

[PKPoole]

MTribe,
I'm only guessing here. It may be just a water leak, but the powder looked a lot like what you see when galvanic corrosion occurs. Generally, it is caused from contact by dissimilar metals when low current is allowed to flow through them (a circuit has to be created, and the two metals create the "battery"). You see it in waterborne objects where the water allows an electric circuit to be completed. Since this is steel on steel, maybe there's a copper, aluminum or lead gasket between them. Good luck.

 

[sp53]

Did the rebuilder blast the block with baking soda?