“Oil Pressure Too Low” & Squealing Noise

[Harness]

While I was driving, I got an “Oil Pressure Too Low” warning and the car was making a squealing noise. Oil level checked ok and it wasn’t leaking anything. Video attached. 2008 C2S with 89,000 miles. Just had oil changed a 3-4 months ago at a professional, PCA trusted shop. Any idea what this is? Car will sit where it’s at and I’ll have it towed next week, but curious if anyone has thoughts or similar experience. 

Edited August 16, 2019 by Harness
Video

[jaybart]

If oil level is ok my money is on the oil pressure valve spring. Had to do this on my 06 where the spring got tired and hence the pressure regulation was out of whack. Simple fix from that I recall. 

[Harness]

Was it squeeling like that? I had trouble uploading the video but the second one should work. 

[jaybart]

Nope. Sorry, hadn’t had a chance at the video. Sounds like a bearing but could be many things. In cases like that I like to use a stethoscope (like this 

Mechanic's Stethoscope

WWW.HARBORFREIGHT.COM

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Mechanic's Stethoscope

)

the one I got comes with a little funnel to help locate the noise. 

[Harness]

Update: This turned out to be the oil/air separator

[jchapura]

I'm surprised that the failed AOS caused the low pressure warning. I hadn't read that low oil pressure was a consequence and I've had a failure while driving and I had normal oil pressure for the balance of the short journey home.

[Harness]

Just realized I didn't put in all of the details. One of my idler pulleys had also failed... I ended up replacing all three of them and the belt, and that "probably" solved the low oil pressure warning (probably, as that never came back but I only drove 3-4 miles after that point). The squealing returned after the pulleys were replaced and once the engine was warm. At that point I was properly spooked and had the car towed to my mechanic, and he diagnosed the Oil/Air separator. Interestingly, he did that by removing the oil cap which caused the noise to stop. He put his hand over it and noted a high level of suction. Once he got the separator out it was clear it was failing.

[jchapura]

Excessive crankcase vacuum is definitely a symptom of the AOS having failed. A couple of years ago, I made a homebrew manometer and captured the "inches of water" value. After the AOS failed, but I hadn't yet fully confirmed it was the AOS, I hooked up the manometer, and lickety-split, every inch of that water got sucked into the crankcase. I should have guessed that would happen but I stood there dumbfounded for a second then shut 'er down. Drained the oil. Replaced the AOS. Warmed up the car. Drained the oil again. A $120 for the extra oil change. Ugh.