I'm curious if anyone knows what this is. For some reason it doesn't have me too concerned, just a bit annoyed.

When I start the car cold. It starts right up and I'd say after just a few seconds. (3-5 seconds?) There is a brief noise. It lasts maybe 1 second. It kind of sounds like a playing card in bicycle spokes. Just for a second and when it does it the rpms drop significantly. After that 1 second everything returns to normal and it runs fine.

Any ideas what it is? If it's harmful? I don't have any way for data logging.

 

well i have heard this on some ecotechs but it happened right at start up then went away and it turned out to be the cam phaser. If it does it every time take it to you're dealer.

 

Damn...

Alright man... Thanks for the info!!

 

Sounds like you're describing the direct injection but that doesn't go away after a few seconds.

 

Yeah this is much different. Much louder than the direct injection but just for a second.

 

i noticed that too...but it doesnt happen all the time.....just off and on

 

i know what it is, there is a shield covering the muffler by the back tire on the driver side, im guessing its crack and it rattling the metal on the muffler, it happened to me and like you said made that playing cards sound, i tied it down with some metal rings and it went away.

 

When the car is cold you'll hear a different (and much louder) injector strategy for cat warmup mode. After a little bit you'll hear it switch over to the normal sound.

 

you also have to remember these cars sound strange on start up anyways especially when it gets cold out.

 

Yep, thanks for the help. (all of you!)

I notice today it was slightly warmer (in the 50's) and it didn't do it or at least it was extremely mild. I guess when it gets crazy ass cold out here I'll find out more about it.

 

I had this happen once after washing the car, moving it in the garage and letting it sit after drying. Never done it since but I know the noise you're describing; as for what it was, I haven't the faintest clue, it caught me totally by surprise and went away almost immediately.

 

Back from the dead!! I took a short video tonight of the issue. Because of the dinging on the interior it's difficult to hear. I may take another vid from outside the car tomorrow. If you listen carefully though you can hear it. It's actually much louder than the video would have you believe.

Just wondering if anyone recognizes it and can tell me so my mind stops wondering. I DO have an appointment set up for it to go to the dealer a week from Monday.

Here's the 15 second vid: http://www.youtube.com/watch?v=3e0WKaSv0YQ

 

Turbo solenoid methinks.

My car has done this since I've owned it and it has gotten significantly worse.

 

My 2006 G5 GT 2.4 used to make a very similar noise on startup every now and again. It sounded to me like the timing chain. I figured maybe it happened because the tensioner for the chain is run off oil pressure.

 

my tc has made a grinding type noise before on right on cold start-up,very rarely. worries me, not sure what it is at all but it seems to instantly go away with in a sec to a half sec. so maybe this is the noise you are describing? idk if its deck of cards sound? just a grinding then gone and smooth running and operation all day. just wondering if anyone else has had this sort of noise? didn't notice where rpms were at because its so ramdom and its usually gone by the time i look at the tach.

 

I got it too... a second after start up, there's a quick 1 second long grind noise...
I have free time this week to get my car looked at from the dealership, I have a list of almost 10 things they need to check on..

 

Yeah I've had the same thing happen since I bought the car, probably 10% of the time. Scared me for a while, got used to it, I would love to find out what it is.

 

Mine does it nearly every time. It seems to be getting worse. I take it in Monday and they are going to check it out Tuesday. (it needs to sit for a while because it won't do it when warm) I'll definitely let you guys know what's up.

 

Starter overrun clutch not disengaging?

 

Well wouldn't you know it.

Car acted up for me nearly every single day. Car has been at the dealer 3 days now and hasn't done it. I don't blame them at all. Tomorrow is the 4th day. They are giving it a good shot to get it to misbehave and figure it out. If it doesn't do it tomorrow they will just document it and give it back.

I'm going to ask them tomorrow anyway but does anyone happen to know the answer to this?

I'm nearing the 36K basic warranty expiration already. So if this same issue worsens and I want to take it back. Lets say it's electrical for some reason therefore not under the powertrain warranty. Would they still honor the basic warranty for this issue since it started before the basic expired?

I do have a few videos of it happening, some which show the mileage on the car.

EDIT: Today it did it for them. (They also did the charge pipe recall too). They described the noise as a "ratcheting" noise. They also said it's the high pressure fuel pump and that it's normal. I don't think it's normal for the rpms to drop like that. They didn't say that the rpms dropped which the rpms may not have dropped. I guess from here it's just a matter of it will get worse and cause problems or it won't. Just wait and see.

 

So nothing has change since taken it to the dealer,iver been notice my car doing it. It only last for a bout a second or 2 at first i thought it was me letting the clutch out(car in neutral) to just sit and warm up. But i started hold the clutch to the floor until after the noise just to make sure. Anyways what did they say really, anything to worry about?

 

I've heard that noise once in a while, sounds like a loud "ratcheting" noise as the dealer described. Freaked me out the first time I heard it as well lol, seems to only happen when it's cold out and not every time.

 

I hear this noise all the time. Only when cold out

I had a 2.2L and it was just as loud at start up

 

It's a Cobalt

 

Any updates on the problem, did they dealer say there was anything you could do, my car does it just about every cold start up