Sewing Machine Sounding in Colder Weather

[BamaZ28]

I've had my 2008 G8 GT for almost 9 years now. Never really noticed it until the last few years, but the engine clearly has a slight sewing-machine sound to it during cold weather startups for the first 5-10 mins.

Oil level and pressure are good, all 8 quarts of it (ugh!)

You really only notice it from inside the car, doesn't sound too noticeable from the outside.

Is this a symptom to impending doom, or just the design of these engines?

Thanks in advance for the feedback.

[Napalm]

do you have the engine cover off - that knocks down alot of the valve train noise.

That's part of it. and mines done it for years.

What you hear in the car on cold days is more than likely piston slap however - this is the skirt of thepiston tapping the lower part of the block as it transitions from going down to going up . It's a deeper sound and I would say you hear it more in the car than you do out of the car.

mines done that for years too and it's common on the GM lS v8 family of engines with the LS3 probably doing it the worse.

I would say no doom and it's mostly normal.

[Napalm]

If you can record it thought that might help as there are other noises that could happen and some of those are bad. LIke a lifter going bad - which is common on the DOD (AFM) series engines like the G8GT has. I have a GT also - I had a lifter die and when it did it threw an engine light but only under half or more throttle - because the valve doesn't open all the way. etc.

That's a much louder sound and it doesn't go away on it's own.

[-Ray-]

You didn't say how many miles on the engine.

[sixt9stang]

Video would be helpful but they do usually have some noise. Also I usually use closer to 9 quarts of oil.

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[WhatNext]

Distant past memories brings up that sewing machine sounds during cold starts is valve train noise related to oil/flow/film characteristics. Might want to research this on Bobistheoilguy forums for what oil characteristics to look for that might minimize this. Can't recall if thinner or thicker cold viscosity would help but given that these days synthetic oils flow better, better find the latest info on minimizing cold startup valve train noise.

[madmax032]

My 09 G8 GT (124k miles) does something similar to what you are describing despite having new lifters and no cam damage. The colder, the louder and "knockier"! I have tried many different oil types and viscosities with no change in the sound and I have replaced my AFM filter as well. Blackstone gives my oil a clean bill of health.
I am going to replace the solenoid plate next as a local trusted repair shop told me that they have had to do so on a number of AFM trucks to kill that sound. That all being said, I may eventually just find out that it has piston slap like Napalm mentioned.