bwill03z

I know LS3 motors tend to be noisy, as most LS motors are, but does your stock LS3 have the “sewing machine” light tick around 1500-2500 rpm’s? I know the Z06’s are notorious for it....and I know a lot of cam and header cars have it but I was surprised to hear it on my bone stock 2011. I really can only hear it with the windows up and radio off and it’s pretty noticeable.
I thought at first I had a loose rocker but everything checks out under the valve cover.
Just curious.

jmaci

I had the same problem, turns out it was a loose exhaust manifold bolt, heard the ticking at around 2000 rpm.

bwill03z

It’s a little louder on the passenger side so that’s possible, haven’t put a wrench on them yet to check. I’d be surprised if that were it but it could be

JABCAT

My previous ‘12 GS had it & it became more pronounced after I added longtubes. It was so loud that driving into my neighborhood that’s the sound you heard bouncing back off fences over the longtubes and Corsa Xtreme. I thought I had an exhaust leak it was so loud, but nope.

bwill03z

Yeah, and that’s exactly why I keep hesitating to pull the trigger on ordering some long tubes :/
i know LS motors are noisy and really it’s just the sound of power but damn if it ain’t annoying sometimes and can make ya paranoid.

bwill03z

Uploaded a quick video. It’s not bad, but for stock she’s a bit noisy...

torquetube

Has the sound gotten louder? What's it sound like under the hood?

bwill03z

Since buying the car back in July I do think it has become slightly louder. Under the hood I don’t hear anything going on at idle that I would consider abnormal but the passenger side is a little bit noisier than the driver side. I popped the hood and had someone do a few revs and it sounds okay to me outside of the car but when driving at lower rpm’s with the windows up I hear a very audible ticking. Might just be LS sewing machine noise but I thought it was kinda loud to be stock

BadAV

Definitely hear it in your video. Mine doesn't do it.

bwill03z

So yours doesn’t sound like that at all?

BadAV

No ticking at all. The whole valvetrain is noisy on cold start but quiets down as soon as the oil starts to warm up a little. My 07 did exactly the same thing (and to a lesser extent, my 03), so I just chalk that up to GM's chosen components for the Corvette engine. The 5.3 in my 02 Avalanche never had the cold start valve train noise, although it started getting a little piston slap at 95k miles (75k miles of which was cammed and pullied down Magnacharged).

bwill03z

What is your current car? I’ve heard a lot of cammed cars and cars with long tubes sound like mine, but I don’t know any that sound like mine that are bone stock. I’ thinking it’s noisy lifters but there’s a slight chance it’s exhaust related. I wish I could say mine had no ticking :/
I had an 03 Z06 that ticked like hell too and drove me crazy.

BadAV

It's in my profile - Centennial GS vert. No engine mods other than I slightly tweaked the ecm/tcm tuning to my liking with HP Tuners.

C3w4sp

Start with a mechanics stethoscope, pin point the source. What I discovered was the fuel injectors are very loud! Through the stethoscope the lifters and valves do have that LS sewing machine sound. However the LS3 injectors are on a different level.

I still find it irritating, but the car continues to deliver. I suspect GM knew this as they put insulation on the back sides of the fuel rail covers to temper the sound. Get a scope a probe around, see if you can zero in on the source.

bwill03z

Thanks for the suggestion. I’ve actually already done this and really couldn’t narrow it down to anything definitive, it sounds like that on both sides of the motor and seems to be pretty consistent on all cylinders. It’s just that I feel like my car should be about what a car with long tubes would sound like but mine is stock. I mean it could be injectors but if so that would be surprising because apparently some other LS3 C6’s are much quieter

owc6

In your video, I hear your sewing machine noise, but I will say none of my LS engines ever sounded like that.

Both of my LT engines do do to the DI.

C3w4sp

Did you put the probe directly on the injectors?

bwill03z

Yes I did

Any ideas what it might be

C3w4sp

Well, at least on mine, listening with the scope, the injectors were easily 2 to 3 times louder than anything else.

bwill03z

I’m going to try again with a stethoscope and have someone do some light revs but I don’t see why the injector noise would vary so much from car to car.
I have the worst freaking luck with getting LS cars with noisy motors!