i just bought a 91 n/a from my girlfriends' brother. it used to be mine, i sold it to him, he sold it back to me. anyhow, the gauges that were on the car when i sold it to him were not working at all. we put an aftermarket live feed oil pressure gauge on it and it read 40+ oil pressure. now, the oil pressure is only reading, at idle, under 20. the oil pressure goes up to 60-80 psi when driving in high rpms. what could the problem be? if the oil pressure control valve is bad, then it wouldnt read at all, right? i am thinking that the front cover o-ring seal that sandwiches between the front iron and the front oil pump cover either got pinched, or just cracked. any suggestions on what to do?

 

mine has read less than 20 at idle and about 60 at full tilt since the day i got the engine. you worry too much. thats how much oil pressure there is supposed to be.

 

well, the oil pressure at idle is supposed to be in the range of 14 to 54. that is a big difference. mine use to read 38-42 at idle. then when throttle is applied, it is supposed to read from 64-78. mine read perfect. now the oil pressure dropped. just because it is in the range of spec, doesnt mean it is right, especially when it drops that much. there is something that made it drop that much.

 

My car runs at 30 psi tops when idling at 750 rpm and has been that way since April of 1986. The thickness of the oil probably plays a role in the pressure too.

 

ok, that makes a little sense. ive been using 5w30. probably should use a thicker oil though.

 

also, mine runs at less than 15 at 955 rpms.

 

when it is cold it will read higher, once it warms up obviously lower, your readings sound just fine

if it gets cold where you are you may want to consider putting 10-30 in for the winter.
I view oil pressure like sucking a milkshake through a straw, thicker oil will obviously give you a higher reading but is it REALLY helping?

 

You want 10psi for every 1000 RPMS. My turbo only runs around 10PSI fully warm at idle and 50's at 3000RPM. I'm not worried.