Td 7h , help repairing

Ok not a dozer mechanic but can fix damn near anything but need advise, late last fall dozer started losing power and after 30 seconds stalled , a big pop noise and a small fire (only oil burning) pulled cover and found return oil line from head over to block blew...melted bad , why ?.. repaired , replaced and started right up and ran for 30 seconds ..LOST power and stalled , would not start after that , only tried for a few minutes , never lost oil pressure , not over heated....now been...

Td 7h , help repairing

Td 7h , help repairing