Low Oil Pressure

so i have done searches around here to try to find out just exactly what the deal with my oil pressure is, i have a 1995 Bonneville SSE with 156,000 miles, recently right after i changed my oil ive noticed that when my car is cold the oil pressure is right at about 40 as the engine gets hotter it very slowly goes down when idling it usually ends up right about 12, it doesnt go down rapidly, i have to drive it like maybe 45 minutes before it goes that low, usually goes down faster on hotter days, and right now its hot, ive heard of the oil sending unit could have to be replaced (where is this i tried finding it by using one of the pictures on here particularly the one with the green plug picture but i couldnt find anything that resembled that at all) or the oil pump but im not so sure that would be it or at least i hope it isnt, when the oil gets hot it tends to leak a little bit on the back side of the oil pan and a small drip off the oil filter, the oil pan one i would think its the gasket but im not sure on the drip off the oil filter


the current oil in it now is Amsoil SAE 5w-30, ive heard of switching to a thicker weight of oil but i live in minnesota and it tends to get cold in the winters

For the summer switch to a heavier weight oil like a 10W-40 you can switch back to the 5W-30 in the winter. 12psi at idle when hot is not that bad for a car with that high a mileage as long as the pressure increases as engine rpm's increase.

The oil dripping from the pan probably is the gasket leaking. As for the leak at the oil filter, check the gasket on the oil filter it may be leaking. Also the oil pressure sending unit should be located just above the oil filter. It looks like a small round can with a wire coming out of the end. Not hard to replace but may be a bear to get to.

thanks for the reply so fast, ill try a heavier weight the next time its do for a change, i noticed that can with a wire looking thing above the oil filter but wasnt sure because it didnt look like the one in that picture thats around here somewhere