Originally Posted by
MB
I had choked up my old DX4.2TD bonnet years ago and to the best of my memory what NNB and Poindexter have kindly posted above makes sense now. It did seem to help at low speeds but that high pressure zone pictured above at the windscreen base must have been the issue at high speeds. Reckon I'll still give the cheapo Saas reverse scoops a go somewhere in the middle of the bonnet low pressure zone. My NA truck finally goes up to Mansfield later this week for a free flowing new Millweld bar with built in oil coolers far left and far right and I'll piss off the last flexy top radiator hose too thanks Kimbo :-)
Rainsey mate, in regards thermostats, I researched heavily the yank sites from posters in the snow and desert regions, consensus seemed to be the ACDelco 88DCelsius for best all year round. About $40Aud each from Autobarn-USA online.