[Flying]

Originally Posted by jrshooter

here is a odd one
what ever they spray inside the water pipes [looks like paint] flaked off and clogged the radiator. cleaned the old ones with a bore brush, orderd new ones, but the new ones have the same finnish inside, afraid to put them on, so i bring them to the track as spares.

It's probably e-coating, paint that's bonded electrolytically.
https://www.rit.edu/affiliate/nysp2i...cess_final.pdf