It was cold here in Illinois this past weekend, and when I was out and about the engine temp never got any higher than ~150 degrees. So I went and ordered a cold weather cover for the radiator from DC. From what I understand this will have adjustable flaps for temp control, so at what point do you leave them all closed versus opening one up here and there?

I had left the trcuk running a bit after I had stopp ed after driving for about 40 minutes, and at idle the engine temp dropped another 20 degrees. Man these things are cold blooded! A guy at works D-Max sits at about 220 degrees when up to normal operating temps, but I do not think I have ever seen above 180...is that about right (even when it is not cold)?

 

Yeah, that sounds about right. I'm on my 2nd 04.5 CTD (nothing wrong with the first, just traded it in for a dually) and both acted exactly like what you describe when warmed up.