I have a 79 300d with about 160k that has been having some new issues lately. I think it started when the car overheated on a long trip a few months ago. Since then it has progressively gotten smokier and lost some power. As the smoke has gotten worse the fuel economy has also gotten worse and it idles fairly rough. It is especially lacking in acceleration from about 0 to 10mph. The smoke is whitish grey in color and is especially bad when starting. I've read on here that this may be a coolant issue which would make since as it has also started going through coolant fairly quickly and I can't find any leaks that would explain the amount that is lost. Starting is also a problem - it used to start alright down to maybe 20 degrees, and it is currently about 34 and it won't start. Recently it has also been skipping some cylinders right after starting. After it warms up a bit they all fire. It has a good alternator, battery, and glow plugs(the pencil style). It is also overdue for a valve adjustment. Any advice/things I should check?
Thanks