So here’s what I’ve got going on. I have a 97 Camaro z28, LS swapped of course, and I am at a complete loss, but I have my theories, and I need to make sure I’m not completely crazy. I got the engine in the car almost 2 years ago, it’s a 2001 LM7 that had around 140k miles. It’s got LS1 oil pan, LS6 intake manifold, EV6 injectors, and an ICT billet accessory drive. I’ll also add that it’s got a build t5 with a brand new hydraulic throw out bearing, and a brand new pilot bearing. Now here’s come the issue I’m having. This thing has just a horrendous screech coming from the bottom front of the engine. It’s had this noise since I’ve got it running in the car, but wait, here’s the kicker. The noise ONLY happens shortly after the car reached operating temp, and slowly goes away for the most part as I continue driving it. At first, I thought it had something to do with the clutch, so, as a reasonable person does, I basically replaced every single clutch component that could possibly be making that noise. No dice. Still does it. Now after still dealing with the noise for a while longer, I was driving it home, and happened to glance at my oil
pressure gauge while it was screeching so loud I couldn’t hardly think. The thing was jumping all over the damn place. I never noticed that, mostly because I would glance at it when I’d first start it up when it was cold, and it held steady at around 40psi. So it got me thinking “could it have something to do with my oil pump?” I know. Crazy. But is it though? That’s what I need help with. I can attach a video of the noise later today, but has anyone had any kind of experience with this before? Any ideas, thoughts, suggestions? Thank you guys!!

*to edit, yes it still makes the noise with the belts off, so I know it’s not the belts or the pulleys.

*edit 2 here’s the link to view the videos I took of the noise: https://drive.google.com/drive/folders/1WNOZrTD6JiBJ4xUuTnoUijH8eCuIfmSu

*edit 3: yes I’m crazy. Using the stock LM7 valve covers I had the fresh air line routed completely wrong (as in it was connected to where the PCV is SUPPOSED to go) which was creating vacuum inside the crankcase. It’s now connected correctly at the cold air intake post MAF but pre TB and no more squeal! Thank for everyone’s input!

 

Make sure you use the right bolts For the camshaft retainer plate. They are the same thread as the oil pan, But the ones for the cam plate are shorter. If you put a longer one here it would be hitting scraping scratching on the front of the crank there

If you think it's the oil pump and you decide to pull it off check here as well

 

Doesn't sound like anything an oil pump could do. Not bloody likely anyway.

Won't offer a comment on whether you're crazy.

 

The engine is Bone stock other that the upgrades to make it work in the F-body car

 

what I’ve been reading on the 5.3 vortec motors is it’s entirely possible for an oil pump to make the noise I’m hearing, I’ll have a video of it shortly.

 

Negative. If it’s making a noise like you’re describing, and your sure it’s not the front accessories, you need to dive in. something is hurt.

 

Cut the filter asap before doing much more. If it’s clean, we’d question the water pump.

 

How is your pcv routed? If the crankcase has too much vacuum it will suck past the seals and screech or whistle.

Take your oil cap off while its doin it and see if it goes away

 

I took the oil cap off, TONS of vacuum. Lo and behold bad PCV, replaced it, it’s operating correctly as far as from the intake to the valve itself, but still, TONS of vacuum. If I take the oil cap off, or the PCV off the screech goes away. Any thoughts?

 

I had a 99 CRV that did the same exact thing. Skreeched like hell with the oil cap on and PCV system in place. Take the oil cap off and it would stop. From what I could gather the thrust bearings were toast and that allowed the crank to move in and out and the flexplate was hitting the block.

 

The LS is notorious for oil mist buildup in the intake and the PCV tubing. Take all the PCV tubing off and clean them out…prolly stopped up. My brother had a suburban with a 5.3, he bought new. After 200k+ miles he was having a strange issue to where he would check the oil right after shutting it off, and it wouldn’t register on the stick. It was wintertime. Turns out, the PCV lines had so much built up oil-mist AND condensation that the condensation was freezing in the lines because they were so yucky it couldn’t vent out. This was causing the engine to not vent…lines were froze up…so the oil was taking forever to drain back to pan. I pulled the oil fill cap off and the oil was literally to the top of the fill tube. Just a thought…

 

On the other valve cover where do you have the fresh air line running? Ypu are using stock lm7 valve covers/pcv system?

 

okay, so I am an idiot!
I had the fresh air line going to the complete wrong place, which was creating a vacuum inside the crankcase. It’s now routed to the proper location, and no more squeal!!

 

Beats the hell out of messing with an oil pump.

 

Nice...easy day