My car is making a paddling (best comparison I can think of is like when you put a piece of paper in a moving house fan) noise upon start ups randomly. This happens at start up for like 3-5 seconds then goes away.

It used to be few and far in between randomly but now its every day one start up a day.

I originally thought it was my cam phasers just doing its thing but now I'm more worried there's issues. Do I need to get it looked at?

 

I think I used to have the noise you're talking about. It starts out incredibly loud and quickly quiets down to the point where you can't hear it anymore? I always thought mine was coming from the passenger side of the valvecover but could never figure it out and it would do it infrequently as well. If you do get it looked at I'd be curious what they say. Since I had my valves replaced it has gone away seemingly for good, but I can't say that with 100% confidence because it happened maybe once a month if that.

 

maybe a lash adjuster?

 

Damn, well I hope it's not serious. If it is the lash adjusters, what are the side effects; Lower power, louder exhaust etc.

 

well if the lash adjusters broke, or are loose i think they can cause damage, im not 100% sure on the specifics, maybe someone more knowledgable can pop in, have u over revved your car at all mike? like tagged the rev limited?

 

I have tagged the rev limiter a few times at the track or on the highway, like where my car slows down because I shifted too late, but that's at stock redline

Also, when I had ZZP Canned tune i had a higher redline that I messed with a few times, but that was last November, I got Trifecta and restored my stock redline in February I'd say.

What I don't get is my car runs fine and acts normal. There's nothing that I can tell is wrong. It doesn't do anything odd except that... well sometimes I feel like it's slower than it should be.

 

from what i have read, u dont really notice lash adjusters being broke, they just kinda happen, now i may be totally wrong, but if i remember correctly someone didnt even know theres were broken untill they pulled the valve cover and saw them laying there, call brian and have him look at it mike, and if he cant do anything take it to the dealership for warranty work, swap your charge pipes really quick and ur good

 

The noise you described happens frequently with Cobalt turbos with air intakes installed.

What happens is the maf sees high speeds and volumes of air coming into the engine due to the aftermarket air intake flowing better than stock intake. This only happens at cold start.

It then opens and closes the factory diverter in an effort to purge some of this air.

Im going to assume you have a aftermarket air intake installed on your car.

 

he has the ZZP Intake Tube and airbox mod, and nice i think he also has the forge DV

 

This is true, I have all these

 

I could be wrong but I don't believe the ZZP intake tube would allow something like this to happen, considering the MAF sits in the stock location and isn't really seeing a whole lot more air? However, couple that with the modded airbox and who knows?

 

I've had the same thing happen on and off for almost two years. Oddly it hasn't happened in a while. I actually forgot about it until i saw this post.

 

Well I was relieved until I saw this.

I will get my valve springs soon and check them out then. Maybe all will be good when that happens. .

 

Mine would do it with the solenoid that controls the BPV completely bypassed. It's straight to the intake manifold. Mine would also do it more in colder weather it seemed but I guess that's nothing to do with it. Anyway.... check this thread.

https://www.cobaltss.net/forums/2-0l...art-up-194165/

And this video.......

‪MVI_5188.avi‬‏ - YouTube

Personally.... I think it's something to do with lower quality fuel and the mechanical high pressure fuel pump. (which you'd find more of between the months of Nov. - March because of "winterblend" gas)
Look for a "Top Tier" gas station near you if you aren't using one now and see if that helps. I may be wrong, it's just a theory, but never hurts to try.

 

Yea, let us know how it goes. I'm having these same symptoms.