Blown head gasket.
Yes
i like an axhaust diagram for a 1999 chevy venture
If it is motor oil in the anti freeze, then it is either a cracked head, cracked engine block, or a head gasket blown. If it is transmission fluid in your antifreeze, then the radiator is leaking from the transmission cooler ----- although usually that would cause antifreeze to be in your transmission fluid.
Blown fuse? Bad relay? Bad temperature sensor Bad fan motors? Check to see if the fans are getting power if so motor is bad If not check the above
If the Chevy Celebrity radiator is smaller that the Saturn radiator it might well overheat from not enough cooling capacity. If the Chevy Celebrity radiator is the same size or larger than the Saturn radiator I would think it would not over heat.
The heater core has gone bad or possibly a hose leading to it or away from it has gone bad.
Need to check the coolant level in the Radiator, it is probley low on coolant. The heater core could be 1/2 stoped up. Can switch the hoses around on the heater core and go drive it, It will flush the heater core.
how to take strut off of venture van would like to see diagram please
Usually the fuse is going bad.
Bad switch? stalk bad wiper motor? bad low speed winding
Radiator cap
A 3 or 4 core radiator would be your best