Let'* reference this thread for my feelings and comments.
It'* much easier than me typing the whole thing again. Short response though is don't ever trust a dash gauge. If you are wondering what the oil pressure is, please have it checked with a mechanical gauge.
Coolant: if you are using 48oz of coolant every 1k or even 3K miles, please..find the leak. You shouldn't have any significant level drops over a year. A little down a little up depending on weather and temps is normal. A constant drop...you gotta leak to find.