The timing chains on 103 motors are short which translates into more durable. Unless the oil was seriously neglected, this component is not an issue.
I agree with ILUVMILS introductory coment. If it's a daily driver, it might last a good long time. Lack of heat could simply be a diaphragm for the heater control valve more commonly known as the monovalve.
It all depends on what you want - a show car or a daily driver.