Well I have my opinion but I want to hear from people that know. Check out these scratches tell me what made them they are in all cylinders but this one caught my eye that alerted me to the rest. There is brown in the scratches, kinda of a mixture of nasty oil condensation and rust but it wipes off. The engine has been sitting awhile. Now, I can't hardly feel them with my fingernail, but I can with my finger.