T&T: "Monkey Sh-t"

[John Tones]

some of this packing material... problem is, I only know the Navy slang name

Mike - I think what you are looking for is "Duct Seal" and if you Google 
for it there are lots or hits although we used to have another "slang" 
name for it in reference to bears but that was probably because there 
are no monkeys in Western Canada!!!.
I have used this product for years to do just what you describe both in 
the marine and land communications field. It is gray and has the 
composition of kids play dough, never hardens and can be re-used for 
ever. The product made by Panduit is rated for use from -30 F to 190 F 
so it would work even in your engine room.
Hope this helps
John Tones  "Penta"
Sidney, BC