REVISED - I LEFT OUT - Contribution of Waterpump to Lack of Cabin Heat. A good hint that the waterpump can be bad!
There are a number of possible causes for the various symptoms associated with an engine overheat. This chart covers most of them. Some can be readily observed by the owner/operator. A few others require a few tools and effort to determine the cause of an overheat. The remedy is most often associated with the servicable item that precipiated the overeat condition (or a combination of factors).