Hello everyone.

This is my first post, so I apologize if I am in the wrong section.

I have a 98 expedition. 6 months ago I smoked the motor, so I put in a used motor (saving money) that was in good working condition. Immediately, I noticed I no longer have heat, but haven't done anything about it until now.

I noticed my coolant was pretty low, & there was rust in the surge tank so I topped it off.

The tank continues to over-pressurize & spill out when I fill it back up.

There is no oil in the coolant, or coolant in the oil.

Any thoughts? Possibly a couple different issues, but not sure.

Any and all help is greatly appreciated, & I thank anyone in advance for their advice!!