I commute 60 miles each way daily and lately have noticed that my oil pressure gauge is all over the map. When I start in the morning, it register about 75 psi for the first 10 minutes then will drop down to 40-45 range, and then down into the 30-40 range. I've noticed that at times when I'm into the trip for about 50 minutes the pressue will start droppin down towards 30, then 15 and sometimes even towards the zero mark. This is in 5th gear at about 2300 rpm, 65 to 70 mph range. I can drop it into fourth and it'll go back up to 45. Put it in 5th and it'll stay in the 30-40 range, sometimes for the rest of the trip, sometimes it heads back down to the 0 range. Or, I can leave it in 5th and accelerate toward 3000 rpm, 80-85 mph and it will rise back to 40-45 psi. It never makes any unusual noises. Other days it is just fine.

Is there a potential oil pump problem or just a fluke in the gauge. Anyone else experiencing this issue. This might have been happening for a while and maybe I just noticed it recently and am paying more attention to it now. Thanks for your help.

 

mine does that too. I have an auto. The chilton says my car reaches it's peak torque @ 3200 rpm and the oil psi should be about 57.
When I start in the morning it almost gets to 45psi, by the time I get to work it's close to the 0 mark. I think that its just that in the morning the oil is thicker because it's colder, when it heats up and expands a little there is less pressure. I wouldn' t worry about it unless there are blue clouds of smoke coming out the back. Or if it's eating a lot of oil.
Peace

 

That seems normal. When I start up cold, mine hits 90 psi. Stays there for a little bit, then drops down to 45. When it gets warmer, it will hover down around 15, but when I go again, it moves back up to 45. When I start hot, it sits on 0 for a little bit, and gradually comes up to about 15 if I let the car idle. So I wouldn't worry too much.

S

 

Thanks for the replies. No smoke and it uses about 1/2 a quart between changes (every 3000 w/filter). It has a few minor leaks and that is where I think I lose oil from.