I considered three gauges on the 6.4. There is room for three maybe four on the pillar. I never got around to it but was considering EGT, rear diff temp, & lift pump fuel pressure.
Amp gauge would be great. See how the camper battery is charging.
My old Chevy 6.5 I added those as well as trans temp and oil temp.
EGT is the most important as you can use it to adjust your driving for best overall results. Rear diff temp is handy but probably not necessary if your not pushing the weight limit. The old Chevy was a 1500 so I was pushing the tow rating way past the limit. When the diff got hot I let it cool off. Added a cover and synthetic oil and it dropped considerably. Didn't need the temp gauge after that but it did the job. Not really sure about the fuel pressure on this but on most older diesels it was very important. The truck would seem to be fine until the injection pump went out. Hopefully on these the computer would say something. The fuel pressure is great if you modify the trucks fuel delivery to see if you need a better pump.
One might go with a dash daq and have it all if you don't mind the digital display. I prefer actual gauges.
I would expect it to peg out when cold. Slowly drop as the oil warms up and settle at some point. Slight fluctuations with load and rpm. Had one of those plastic oil lines break inside a car and it made a heck of a mess. It never did much other than that. An electronic gauge would be much better. Less chance of oil leaking somewhere resulting in no oil in the motor.
I guess the theory is that you can't do anything about it so why look at it. Temp is more useful than pressure. You can always adjust what your doing or stop and let it cool off. When oil pressure drops your done. Pull over and call a tow truck. A light coming on can do that just as well.
Last edited by DavidPhillips; 05-05-2011 at 10:35 AM.