2008 Saturn Vue XE low oil pressure warning

infj23

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#1
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MAKE: Saturn
MODEL: Vue
YEAR
: 2008
MILES: 175,000
ENGINE
: V-6
DESCRIBE ISSUE....
I previously posted about this issue. A few months ago, there was an occasional flicker of the oil pressure light (only while at idle). The warnings became more frequent. I replaced the oil sending unit.
At the last oil change, about a week ago, I used Gunk engine flush, and changed the oil and filter.
I have maintained this car for over the past three years and oil changes have been on time.
The low oil pressure warning is now quite frequent, usually once or more per trip.
The engine performance is fine with no unhappy noises like grinding, or seizing, or clanging.
Any ideas? Is the next step to put an oil pressure gauge on it? I don't have one, so I'll have to buy one (and will if necessary).
Thanks in advance to all!
Doc
 

billr

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#2
How do I say this kindly, since we don't mean to chastise folks here, only help them...

Whenever there is any indication of an engine oil-pressure problem, plugging in a reliable gauge to get a true reading of pressure is the first thing to do, never "the next step".
 

nickb2

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#3
Can you tell us which V6. Is it the 3.5l or the 3.6l?

Specs for the 3.5l is 30-45psi @ 1850rpm

For the 3.6l it is 10psi @ idle.

Location is different for these two blocks. So specify please. On the 3,5l, the oil pressure sensor is located at rear of oil filter adapter, and on the 3.6l it is at the front of the oil filter adapter.
 

infj23

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#5
Hello billr and Nick2b,
And yes, thanks to billr for being kind. It is one of the many reasons I'm a frequent flier and sponsoring member here.
And now, the rest of the story. $80 lighter and I finally have my very own oil pressure tester. Thanks to Nick2b for the 3.5l specs on this, which the car met!
Pretty much immediately at start up and at idle, 35 psi. At 1850 rpm, 42 psi. Revved up a little and pressure went up some. Back down to idle (still 35 psi). Back to 1850, this time about 40 psi.
So, that tells me the oil pump is good. Right? I previously replaced the oil pressure sending gizmo (the thing I had to remove to put the pressure tester in place).
So now, what it the next step (now that I have completed what should have been my first step :))?

Thanks to all!
Doc
 
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#6
Have you tested pressure when engine is fully warmed up, at idle, in Drive, with your foot on the brake? Those are the conditions when oil pressure is typically the lowest.
 
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#7
80 bucks for an oil pressure gauge now, ha, paid around five bucks for mine made by US Gauge in the USA, but this was around 60 years ago, still good, just a standard 100 psi gauge with a short hose on it with various adapters.

These crazy things.



Just have a concave disc on the inside with closed contacts, hitting them with about 2.5 psi air pressure, doesn't care whether its air or oil, opens that switch that removes the ground. If that wire is hitting ground someplace, that light will come on. Have no idea who figured 2.5 psi of pressure is good.

Cars made up to around the mid 30's didn't even have an oil pressure gauge, then around to the late 50's were using a real oil pressure gauge on the dash, if the fittings were loose, would have hot engine oil dripping on your pants leg. Was sometime in the mid to late 50's they came out with this stupid switch. That is went I had to buy a real oil pressure gauge.
 

nickb2

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#8
As dan stated, always best when engine is dilated. But if your getting those specs, I would assume your are good to go. From memory, those oil pressure sensors suck large. I think they were made in china. No offense to the Chinese.

I remember getting one out of the box. Said box stated it was OEM. I had to order a new one again. Lost three hours shop time. And added bonus, I looked like a fool. Worst is I knew it was a throwaway universal. Should have followed my initial instincts.

Some parts just need to be OEM. Pressure sender is one of those parts.
 

billr

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#9
Agreed, be sure to check pressure when engine is hot; but I'm betting this is a wiring or dash cluster problem. Does anybody know if that sender is a switch or is it an analog sensor? How about a schematic, so we can all guess *intelligently*? I gotta ask... is the light still flickering after all this fussing with things? The final verdict on the oil pump would require putting a tee at that pressure port, so that both the temporary gauge and the light system are active at the same time; then see if pressure is OK while the light if flickering.
 

infj23

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#10
Thanks to all for the help. The problem is still a problem.
I finally got the time to put the pressure gauge back on to do the test Mobile Dan suggested. Same initial results as last time: pressure about 35psi from start up and to 1850 rpms. After letting it warm up (coolant temp was at 190), I applied the brake and shifted into Park. PSI dropped by about 2, so down to 32-33ish.
Sound like this is a wiring problem. The wire from the sending unit disappears pretty quickly. It is wrapped pretty well with shiny metallic tape, which does not appear to have been damaged. Hard to tell because it is hard to see, but that end looks OK.
Where would be my next best place to look for whatever is causing this problem.
By the way, my daughter has since deduced that it happens more frequently in wet conditions, but she could be just imagining that. When it does ding at her, at the next stopping opportunity, she turns the car off, then back on, and the dinging/warning does not return.
Thanks again! Really appreciate the help!
Doc
 

nickb2

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#11
It is wrapped pretty well with shiny metallic tape, which does not appear to have been damaged. Hard to tell because it is hard to see, but that end looks OK.
Sounds like a shunt wire pressure gauge wiring. Pin test those extremities to make sure, and wiggle test the harness. If with a NEW pressure sensor and still dinging, probably a wiring issue.

This an old thread, and I see the problem is still there but engine is still alive. So that says a lot.

I think my old idea is still a good one, a good old "auto meter" gauge and then you know you have reliable info.

Good luck. Check the old wiring's provided, I am too lazy to post them but will give it a try.

Screenshot (597).png
 

nickb2

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#12
So what I am seeing in this diagram is, the 5v ECM rail pin # 41, gray wire through oil pressure sensor, then black wire to ground to ECM ground pin # 34. I do not see a shunt wire harness here. But maybe the schematic is not showing me that. Normally a shunted harness has an icon that looks like a loop/circle going around the harness and I do not see this in this schematic snapshot.

That is why I recommend a reliable oil pressure gauge which will not be affected by interference if in fact it has a shunt field.

However, if there was an actual oil pressure collapse/catastrophic, and it was shunted, I would imagine this is a normal feature and engine would shut down immediately to prevent engine damage.

So, my question is, is the dinging noise due to a bad reading or a cluster malfunction?

This is a nice thread, it has my neurons going.

Good luck and hope the wiring helps, but not much there, it's only two wires, until you get to the IPC or BCM, that is a whole different beast.:cool: Has this car been interrogated for U, B and C codes yet?
 
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nickb2

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#13
The reason why I ask this, is that it could be a BUS/MUX line communication intermittent problem. So seeing if any other codes are present should determine that. A bad oil pressure reading should code right off the bat. The PCM will code normally for this.

Ok nuff of my BS, post back, you have good oil pressure, but it is still dinging, just bypass the damn thing with a reliable auto meter. ;)
 

kev2

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#14
before we reengineer this, time and $$, anything changed over time, different oil, oil FILTER, a old issue with anything ie charging, idle, temp ?

3.5L? is a honda engine... makes info a 2 place search.
You did use the correct OEM sender?
Did you check TSB's ?
 
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billr

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#15
Nickb2, those "screen shot" schematics you have been posting are too small/blurry for me to read; and I haven't found a way to "zoom in" on them. I can't help much here without a readable schematic.