2005 xc-70 slowly decreasing oil pressure

xc70newbie · Post by **xc70newbie** » 10 Apr 2022, 15:10

hi everybody.

i had the oil pressure warning....so i put a mechanical guage on it.

at startup...i get 50psi.....during 10 minutes of idle the oil pressure slowly reduces to 15psi.

im trying to get opinions? the cracked O-ring on the pickup? or the oil pump itself? or a clogged oil pickup screen?

do you think a shadetree mechanic like me can remove and replace the oil pan?

kindest regards
jason

Post by **jonesg** » 10 Apr 2022, 21:25

try this. doesn't look too difficult.

Post by **cn90** » 10 Apr 2022, 22:30

Wait a minute, that is normal...

How many miles in your car?

Why did you measure oil P to start with?

All cars do that: when COLD, engine oil pressure is 30-50 psi at idle, as engine warms up, the oil becomes
thinner, and idle oil P will be around 8-12 psi or so, depending on car...

Post by **abscate** » 11 Apr 2022, 03:57

I agree that it’s not clear there is a problem

Once warm , a rough rule of thumb is that an engine should have 10 psi pressure per 1000 rpm

It can be quite low at idle, below 10 psi

The oil light pressure switch closes at X psi, to be researched and posted.

Remember your manual says the oil light can flicker at idle after hard driving, which is normal.

You are in Michigan. You can get anything car related done.

xc70newbie · Post by **xc70newbie** » 11 Apr 2022, 07:46

thanks for the vote of confidence!

oil press was 75psi at start and like 15 after a very warm idle.

i measured oil pressure it because i got the red oil pressure warning light after a few miles of driving.

also.....

when removing the stock oil pressure sensor....it was QUITE loose and the connector was barely!! inserted (most likely due to previous owner and difficult to reach switch)

there was no oil pressure light with the sensor completely removed ...i was expecting a fail-to-on logic .

so a loose connection would have NOT caused a warning light

Post by **abscate** » 11 Apr 2022, 08:33

Right. It works by grounding at low pressure, so the wire and sensor has to be snug and firm

xc70newbie · Post by **xc70newbie** » 11 Apr 2022, 11:37

oh...180,000 miles are on this 2005 xc70

Post by **abscate** » 11 Apr 2022, 13:46

It’s not quite broken in yet

Post by **vtl** » 11 Apr 2022, 13:52

xc70newbie wrote: ↑11 Apr 2022, 11:37 oh...180,000 miles are on this 2005 xc70

: 267k.png (1.13 MiB) Viewed 1150 times

Post by **- Pete -** » 11 Apr 2022, 21:32

I took a vanity shot just prior to crossing the 300K border, turned out kinda cool

(this is more current, and not as cool). I’ll see if I can find it.

Oh, are you getting the “NO OIL PSI, STOP IMMEDIATELY” message in the DIM or the red oil psi light?

If the former, I would heed all notions & sensations of caution until proven otherwise.

The oil pan removal/cleaning/etc (& the likely forthcoming PCV job) is a great first project to learn on. You really won’t know why your oil psi is negligible until you investigate further. Surely, your oil pump is still good, rest assured.