Dark oily sand in water jacket - anybody?

[Bryan]

Behind the rear core plug I had a lot of sand that was dark looking. When I dug it out it would burn momentarily with my torch. Believe it is oil.   Could not find a crack between the water jacket and oil galley.  The engine block sat vertical for quite a while with the front pointed up.  HAS ANYBODY HAD THIS IN THEIR BLOCK BEFORE?

[kencombs]

I really doubt there would be a crack in that area, but anything is possible I guess.  But, it is more likely to be ethylene glycol as it will burn.

[FarmerJon]

Or oil from elsewhere ran down to the back of the block. Or someone doused it in a quart of oil to keep the rust at bay.

I wouldn't stress it much, seems like normal old engine nasty.

[Sniper]

Casting sand is generally mixed with oil but I dunno how long that would stay in the block.

[kencombs]

2 minutes ago, Sniper said:

Casting sand is generally mixed with oil but I dunno how long that would stay in the block.

And, it is unlikely any oil would survive the heat of the casting process.  More likely to gas off instantly.

[Sniper]

Yes, but that's the only thing I can think of.  If it were glycol as someone suggested i would imagine one would smell the burning glycol smell.

[kencombs]

1 hour ago, Sniper said:

Yes, but that's the only thing I can think of.  If it were glycol as someone suggested i would imagine one would smell the burning glycol smell.

True, if  one has smelled it before but I'd bet not many have.  The sweet antifreeze smell we have all smelled due to a head gasket failure is not the same as ''hot enough to burn'  outside the engine.

[MarcDeSoto]

It could be the obvious.  Engine block rust.  

[Bryan]

Dang, something I learn at 64. Never knew glycol would burn.  Didn't stick my nose near it. Drinking that stuff is fatal for kidneys.. Didn't want to inhale it. But thanks a bunch I was worried.  Think after having the first engine block with an oil pan full of anti-freeze it spooked me.  On that one I think it was leaking from the back of the water pump through the timing gear cover. Again thanks!   Bryan