In the morning, when I first start my car, oil pressure is at 40 psi at idle; I know this is normal for a cold engine. The other day I was looking at the guage when I was driving, and the pressure seems to be at 15-20 psi at idle, depeding on the temperature. At 3/4-WOT, the oil pressure never goes above about 45 psi.....I don't remember if it did this before, but the guage goes up to 80....should my oil pressure be at 80 when I go WOT, or do you think I'm fine? My friend says I may have spun a bearing, but he doesn't know that much about cars. How would I be able to tell if I spun a bearing, other than by looking at oil pressure? Thanks.

 

It sounds a little on the low side,bet you have a lot of miles.Could be the gauge is off.Mine cold is at 60.Warm idle is about 25psi.You could try a little thicker oil and see if it comes up.Otherwise I wouldnt worry about it.

 

I have a tad under 50k miles on it, but I'm using Mobil 1 10w30...will this weight oil make OP higher or lower than 5w30?

 

That should make it higher.Maybe try 10w-40.I would try getting a new oil pressure sending unit.Any parts store should have it.

 

MY OIL PRESSURE:

COLD:

IDLE 30 TO 35
HIGHWAY 65 TO 70

WARMED UP:

IDLE 20 TO 25
HIGHWAY 50 TO 55

Your oil pressure does sound a bit low. I would monitor it and see if drops more. I would change the oil sending unit just to see if it is failing.

 

Mine is about 40-45psi cold and then 15-25psi at warm idle. You should be fine. Supposedly Haynes and Chilton's manuals rate warm idle oil pressure at 6psi@1000rpm. Havent looked lately at my Chilton's to confirm but if the car's running well and no check gauges light comes on you should be fine. I agree with the above posts, if you're that worried change the sending unit.

 

There are a lot of people with oil pressure just like yours. It is reasonably normal. You could always try changing out the sending unit to see if that makes any change. The senders seem to like to give lower readings as they age (and as engine temp rises).

 

I had to put a new sending unit in after I broke my old one off during tranny removal.
With the new one in its reading a bit higher.