D5diesel - I don't have a dedicated BMW obd reader. I was using the "hidden menu" as described/referred to in my original post. For simplicity, you can see a PDF describing the hidden menu by copying and pasting the following link into your browser address (for some reason I can't make the link shortcut work for this):
http://www.scoopz.com/m5board/E60_Hi...structions.pdf
A link to a similar Bimmerfest posting is here (the PDF is from post #17):
X5 35d engine temperature - Bimmerfest - BMW Forums
The link says it is for an e60, but it works the same on my e70. As I mentioned in my original post, the pdf describes accessing the menu with the ignition on, but engine off. If one does this, though, one does not obtain information while the engine is operating (obviously). No problem, though, just access the menu the same way but with the engine on. To be specific, I monitored coolant temperature on menu 07.00 - as seen on page 12 of the PDF.
So my temps (from menu 07.00) went from 72-73 degrees Centigrade with highway mpg of 25-26 pre-repair, to temps of 84-85 Centigrade with highway mpg of 31-32 after the repair. This is with fairly cold temps in Atlanta recently (ambient temps 20-40 degrees Fahrenheit).
I don't know specifically where the sensor is located that gives the menu 07.00 temperature. I also don't know if there is a sensor that specifically gives EGR coolant temperature. Certainly I couldn't find such a temp in the PDF document noted above.
Hope the info above is helpful.