water in the motor and oil pan

bought a car 91 civic. the motor is a d15b7the guy i bought it from said it had wiring prob but the motor was good the firing order was wrong so we switched it and the motor started. grey oil and antifreeze started leaking from the oil pan i found a crack in the
intake manifold the whole corner (lower passenger side ) is almost falling off could this be the prob or maybe the head.