Attention: TDR Forum Junkies The first time there was just a little coolant in oil mix coming from c/c vent tube. I removed cyl. head and had it magged, it was cracked under an exhaust valve spring. I replaced cyl. head, used marine gasket and new bolts from Cummins. Followed manufacturer repair procedure to install. 3months later got major cross contamination of coolant to oil and vice versa. Removed cyl. head again. Also removed oil cooler. Had both pressure tested,both passed but the surface finish on head was very rough. (swirls and chatter marks) Machinists dont like that, so I had it surfaced to a nicer mirror like finish. New marine gasket and reused head bolts after checking against length specifications I found somewhere. I also checked block surface for flatness and found . 003-. 004 " east to west and . 002-. 003" north to south. I thought was excessive but also thought since my original problem was not a head gasket, I MIGHT be alright. ( famous last words). Ok, so I used same repair giudelines as before and 4 months later I have oil in coolant. The truck is a 97 12v,200k miles,factory turbo,afc moded,I believe it has some other fuel pump mods,not real sure. Big air filter and exhaust. Runs about 32psi under load and 1150*F on EGT. Anyone have any ideas on how to prevent another gasket failure(I'am assuming that is the issue, since I have not yet checked. ) I would be happy to here them. If anyone posts questions I may be slow to answer. As I am not at home much. Thank you in advance. 
