firemangeorge

That's a good way to confuse someone.

Tyler Harvey

No, I'm not using different oil. Only Mobil 1 since day one. ChevyMgr, I have made an appointment for Monday morning.

I'm thinking brake pump or pulley related. Prod, I thought the same thing at first being starter related, but she turns over very easily. Yes, Pitbull76 I'm getting a slight drop in idle as well for that one second. Can't be the timing chain, my car only has 19k. I will let you guys know the outcome and thank you for your help so far.

rroadkilll

Looking forward to hearing what the dealership says it is...

Tyler Harvey

Hello again. So, I've decided to hold off on my appointment until I can pin point the issue. She started fine yesterday (weird). When I talked to the dearlership they figured it could be the timing chain (can't be). Searching the internet on this seems to be very unclear as to what it would actually be. Nobody seems to know. I'd rather head in to the dealership with a answer. I don't want them taking the whole engine apart and not have a solution.

I will keep my eye on it and may be posting on this thread again. Regardless guys, I will post the outcome. Thanks.

XtremeSS

Mine does this Everytime upon cold start up. I had a 2009 SS auto before the 2010 SS 5speed I have now and they both did this. The 2009 never had a brake vaccum installed so don't think that's Wut it is. Im sure its nothing to b worried about.

prod

Hmm, im wondering now if you might be describing the old "piston slap" noise, common on many gm engines. Mine does it too.
If so, I doubt you will fix it short of an internal engine rebuild.

Tyler Harvey

As my quest continues to determine the cause of this issue. When I leave my heater setting on full blast and then start the car, it makes the noise. When I have the heater off and start the car, you can hardly hear it. It's been cooler here the past couple of days. I'm thinking ac compressor or fan related now. Any ideas?

HHR_SS_QC

Tyler, since you have an auto, it could be the brake vacuum pump. This vacuum pump operates for 1 or 2 seconds.

Tyler Harvey

Thanks HHR SS QC, I'm now thinking the same thing, being the second owner, I gonna find out through the dealership to see if the recall was done on mine. Funny thing is, I never had the issue of having to press hard on the brake since I got, mind you I always let it warm up for a least a minute on cold starts. Letting the boost settle is always a good thing.

Laco

It may be the AC compressor on startup. I have a Ford Expedition that does that if it has been sitting for any period of time. Doesn't seem to hurt anything, only does it once when first starting in the morning, and has been doing it for years. My HHR does not do that, but????? Does yours make that noise if the ac and defrosters etc are off. My Expedition does not if all the climate control is off, and will as soon as I turn it on. I also think its related to the freon level, only makes that sound when the freon is full. I say that as once when that system had a freon leak and the level was low, the noise dissapeared, and re-appeared after the leak was fixed and the freon level was restored.