orange/brown gunk in cooling system

[Scott Phillips]

Ameer - I would use a UV Coolant Dye and a Blue/Black light. You put
about 1oz of dye in the system, get it up to temp (go drive around for a
bit), bring it back and start with the light going over the whole
system. 

Biggest problem with this is access into tight areas. The best light for
this is a UV Penlight, small enough to get into the really tight spots
and a LED version will give you allot of UV output.

HTH..

Scott