Update on D8H

I finally got a chance to look at our D8. I fired it up and instantly got a black sooty shower that tasted sweet. The oils is black. I was thinking of taking a 2 inch copper tee and putting it in the return line to pressure up the cooling system, is this a good idea? I already have a used tee with I/4 inch pipe thread where a gauge went so I am not buying one.

Update on D8H