I am not sure what the tstat temp on our dmax's are, 193-195? What I am wondering is if we are running a warm enough tstat for efficiency. I know for pulling when it is warm need to watch it but when I had my 01 7.3 ford we would change tstat to a 203 degree one for efficiency as diesels tend to operate better in that 195-200 range as I have been told. Has this been tried on the dmax or is this not an issue? I know in the winter as we all do that they do not warm up very fast. I am just curious? Thanks.:)