A few symptoms but from what ive read im not sure where to look

And to clarify the motor running hot and coolant disappearing has been going on for several months almost a year, long before the oil pressure started fluctuating.

My sister had similar symptoms - about heating and for her it was cooling radiator. It was full with mud (bad coolant, wrong adding etc). And although we didn't find a place where it was leaking (at beginning) it was one of the on going hoses to radiator, that leaked a bit, but enough for coolant to disappear, because there was bigger pressure in radiator than usually coolant couldn't go through enough fast so weakest hoses started to leak. But that's just a guess. Similar symptoms doesn't mean it's the same cause. About oil pressure - for my dad's bird it was: 1. Wrong oil filter. 2. Oil filter was installed wrong so oil leaked a little 3. Intake gasket was bad So bad smoke, heating up, no coolant and big pressure.

find where your coolant is leaking! the radiator, hoses, heater hoses, intake, heater core need to be looked at if it is going dry. that could be cooking the oil. hope u find the source. sometime i've found small cracks in the radiator and hoses. all should be tight and dry. be sure to slightly open the bleeder above the thermostat to get all the air out too.

Since you see no obvious leaks, I would check places you can't readily see like the heater core (Is the interior carpet on the pass side damp?) or within the radiator fins. Are there other symptoms like rough idling that may indicate a head gasket problem (and the coolant is going out the exhaust)? Jason is right - you must first identify where your coolant is going and then work the fix.

the 3.8 had a problem with a water passage in intake that passes close to the egr circuit and so times it will eat the intake and burn the coolant as you are driving done road and will not show any leaks on ground. as for oil pressure, when motors get hot more than one or more times you can wear crank main bearings and cam bearings and you will lose oil pressure as motor warms up, you have to put a manual pressure gauge to the motor to get an accurate pressure reading, you might have to take out oil pressure sending unit on motor to get accurate , sounds like you might be to late, and have to rebuild motor.