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low oil pressure light on and off

E

elejes

New member
As I posted on another post relating to an identical issue:

My 07 (non supercharged) grand prix started acting weird. My family and I went on vacation and noticed the ”low oil pressure” sign turn on. Checked the oil level and it read fine. I had changed the oil a week earlier before leaving on vacation. Anyway, I stopped at a local auto parts store to pick at a dudes brain about the issue and I informed him I had already traveled over two hours since it went on. We decided it might be a faulty sensor and I took the risk to continue heading home. The light never went on again and we got home safe, (thank God). The car is running fine with no noticeable sounds.
Does anyone know what the issue could have been? How can I tell if the oil pump is failing? Is it hard to install? I noticed the oil level was about 1/2 a quart over on the dip stick, would that cause an issue? Any help would be appreciated.:th_scratchhead:
 


So when you checked the oil the first time it was level and where its supposed to be, then when you got home it was a 1/2 quart past full? I'd say you're getting coolant in there somewhere then adding to the level in the pan. Are you loosing coolant at all?

Other than that, the oil pressure sending unit is probably going bad. It's screwed into the side of the oil filter adapter. You need to get a true mechanical oil pressure gauge on there to be sure what the pressure really is.

And to change the oil pump it's behind the timing cover.
 
Just because oil level is fine doesn't mean the light is a faulty sensor. Oil pressure light is monitoring oil pressure, not oil level. If oil pressure drops below the set amount that will kick the light.

Also, I would bet if you are getting the random light (and the sensor is fine) it means you are about to spin a bearing, so a new oil pump isn't going to solve anything.
 
When they changed my oil before I left on vacation I noticed it was overflowed 1/2 a quart (a week earlier before I left to be exact). The light went off two times. Before we headed home (5 hour drive) and two hours later as we stopped for lunch. The light has not gone off since and the car runs fine with no issues. Like I said, the oil was changed before we left. Any chance the dude who installed the oil filter bumpped the sensor? Is in it near it? Maybe it got full of oil? I will be lifting the car up to double check. Hope it's nothing serious.
By the way, the only thing I noticed was the temperature needle fluxuating a bit, but it was always within the normal aspect. I will be flushing the coolant system and changing out the oil again to eliminate issues.
Thanks for all the help!
 
that sensor cost 10 bucks at any parts store, its located on the oil filter housing,.

i would dump your oil and see if it just oil and not mixed with coolant, if the light is on/flickering 9 times out of 10 its bad news, that light wont come on till theres 5 psi or less of oil pressure. and then boom time.
 


It just hit 90,000 miles. Would a overlow of oil (1/2 quart) trigger the light? Like I said, it has not turned on since Thursday. I hope it's not a major issue.
 
im always at a 1/2 quart low lol no it wont drop it that much.

you best bet is to rent a oil pressure tester, you take out the sensor by the oil filter, screw the tester in to its threaded hole, and start the car, you will now see what you oil pressure is. this way you know if it a electrical problem or if your going down a road of doom.
 
elejes said:
It just hit 90,000 miles. Would a overlow of oil (1/2 quart) trigger the light? Like I said, it has not turned on since Thursday. I hope it's not a major issue.
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I always put 5 quarts in. 1/2 qt over is not too bad, just don't go any more than that or it could cause frothing of the oil.

elejes said:
Is the oil pump replacement:th_shakinghead1: a weekend job?
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Again, an oil pump replacement will NOT fix this issue. It sounds more like potential bearing issues.
 


Is there a number or reading I need to look out for?
scottydoggs said:
im always at a 1/2 quart low lol no it wont drop it that much.

you best bet is to rent a oil pressure tester, you take out the sensor by the oil filter, screw the tester in to its threaded hole, and start the car, you will now see what you oil pressure is. this way you know if it a electrical problem or if your going down a road of doom.
Click to expand...
 
The fact that you said the light doesn't come on until 5 psi is scary and shows GM's lack of attention to detail. Even a 10 psi trigger would be much better.
 


stealthee said:
The fact that you said the light doesn't come on until 5 psi is scary and shows GM's lack of attention to detail. Even a 10 psi trigger would be much better.
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I don't think anyone has a solid basis for that number.

Just conjecture that turned into the tall tale of 5 PSI.

I can say, that the switch was wired incorrectly.

If the wiring becomes disconnected or the sensor fails, the light will not come on as the light only goes on when the circuit is completed. It should be wired to come on when the circuit is broken.
 
no not fact lol but its over most of the time.

being that the op car still runs, im willing to bet hes the 1% where its bad wires or something.

for the life of me i dont know why all cars dont come with a oil pressure gauge. just by knowing your pressure you know when your a quart low.

or if driving a big rig too, the pete i drove had 20 psi warm at idle if it went to 18 it was a gallon low....lol a gallon for real. thats how the hash marks read, 1 mark was one gallon, if you hit the second hash mark it was 2 gallons low.
 
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