I've benn driving my van with the oil mixing with coolant now van don't run

Time for a good used engine.

Intake manifold gaskets are failing allowing antifreeze to get in the cam shaft valley, washes out cam bearings and allows the hollow shaft cam to snap off at the second from rear bearing... Now you have a four cylinder cam in a six cylinder engine.... They don' t run well on four cylinders... Time for a new cam, bearings, intake manifold gasket set, etc.... I removed the entire lower subframe and replaced the engine with a rebuilt engine from a rear end total.... Really expensive repair if you have a shop do it... Good luck...