So I have an Au series 1 manual XR6 with 360,000Km on it.
It has the pressure sensor rather than just an oil light.

I'm noticing that at idle the oil pressure is dropping by about 1 division perhaps 1.5.
Above idle it sits over the center mark, when it drops back to idle it drops below the mark by about the same amount as it is above it.
Only happens when its warm.

I was running synthetic 5/30 in it I've since gone to 15/50 with no noticeable change.

It might be all in my head but it seems that its getting a bit worse of late (could be summer?).

I'm heading into the mechanic tomorrow and we are going to put a gauge on it to make sure the sender is reading right (to rule out an electrical issue, relating to voltage at idle or whatever).

If it is the case, what pressure should I be seeing at idle? Is this something to be concerned about?

as long as it has enough pressure at idle not to trigger the fail beeper and warning light its considered to be ok.
but low oil pressure at idle is usually just a sign of pressure leaking through worn bearings.

if it helps each line on the oil pressure gauge is meant to be 1 bar/ 14psi, so halfway on the gauge would equate to aproxx 4 bar = 56psi

from memory the factory spec is 20-40psi at 2000rpm

just me or is that oil thin for those amount of kms??


i went from a 20w 50 to a 10w 40 and noticed this same issue

im going back to a 20w 50

same car but less kms

Is abit thin I would've thought for 360k km,

I used to run 20w50 in summer in my 300k donk and 15w50 in winter to keep cold start up same thickness as recommended, this was in an EL but anyways, I'd be running atleast 15w50 on a 360k km donk