I'm not totally sure, but the only thing I can assume is wrong is that there's no oil in the top of your engine. This is usually typical on any engine on cold start-ups, and you can hear the noise clearer on a cold day. Think about it: your car has been sitting for anywhere between four to eight hours without circulating any oil through the engine. Gravity is gonna make that oil fall back into the oil pan. Don't confuse this with the oil in the lines (the oil that affects pressure). When you start your car for the first time, it's a little oil starved and so it'll ping for a couple seconds and go away after oil reaches the pistons. It's usually the same noise you'll hear if you change your oil.

 

The sound you hear can, I think, be best described as a bad alternator bearing, if you've ever experienced that you'd know. My 09 TC makes that God awful noise on start up and lasts till the engine temp reaches about 95 degrees. It seems to have gotten louder since the installation of a catted down pipe, CAI, charge pipes and turbo upgrade (more commonly referred to a Stage 1) but that might be just my imagination. The remaining noise goes away at about 110 and at 125 deg the idle comes down as the engine goes to closed loop operation and all you hear is the DI noise which is completely normal. Most of you that are complaining about that noise seem to be up north. That would suggest that post #8 sounds very plausable. "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." I've noticed a little difference since it started cooling off (low to mid 60's with a mid 40 a couple times) at night here in FL. I do believe the noise is engine temperature related. Pay attention to the noise next time you start the engine cold. Let it run, at idle, and listen while watching the temp. gauge. Post the results of your test to see if everybody else is getting the same indications. I ALWAYS wait for the idle to come down before moving the car to allow the turbo to stabilize before moving the car. Just my routine. Can't afford a new turbo.

 

the sound we are describing last for about 1 second, and while it does, my engine sometimes boggs a full 200 rpms

 

Strange!!!

 

I took a vid a few mins ago, and caught the sound...

Im heading to the gym to do some running, this link might not work right away since I'm posting it b4 the video is actually processed...hope this helps..

http://www.youtube.com/watch?v=6gQjHSPqJWg

 

Good vid of it. That's EXACTLY it!

To some of the others: It's NOT lack of oil at start-up or anything like that. The key thing to remember is, the engine FIRST sounds normal, THEN makes the ratchet noise (sometimes followed by a little rough idling), THEN returns back to normal. Remember that sequence....

It's NOT RIGHT AWAY on start up, just shortly after

Dealer just told me the noise was the high pressure fuel pump and that it was normal. They said it shouldn't have the idle dip or go rough but of course it didn't for them. They heard the noise though.

 

Next time you start you car cold turn the Defroster /heater off completely . Turn the fan off and turn the dial to vent and make sure the recirculate button is off . Thats the same noise i hear when i engage the front defroster .....

 

thats the noise, and ive tried everything making sure all heat defrost is off ect, I have been holding clutch to the floor even with it in neutral because a couple of times when i was letting cluth out after start up it made noise and didn't know if there was any correlation. Im just puzzled as to why it does it a couple seconds after start up, ive even left the system prime i guess you could say and turn the key to on and let it for a couple of seconds then start it

 

could be a cracked lifter thats a common problem on some of the lnf's i just had mine serviced for that same problem

 

Agreed, My TC does it and some of my friends TC's do it, its completly normal, and it been getting pretty damn cold here in NH past few weeks so it tends to do it when its cold. But do not have the RPM surge/drop...I'll continue to look at that, see if any customers at the dealership have concerns about the idle during cold start ups.

 

Maybe low quality fuel? Are you buying your 93 octane gas from a high volumn station? Higher volumn = fresher fuel. Computer may be looking for 93 and takes a second to see lower and to adjust. Just a thought.

 

I havnt filled with anything but 93 since I bought the car.

 

Ok let me chime in on this. I listened to the video carefully and what I think I hear is start up cam phaser rattle. First theres nothing mechanically wrong. Are all of you hearing this using the recommended oil Viscosity? If your using a 10W instead of a 5W you can occasionally get a phaser rattle until the phaser fills with oil especially when its cold. However if you get an occasional cold start phaser fill rattle its nothing to worry about. The RPM change is occurring because as soon as the phaser fills it skews the cam timing of the phaser that just filled with oil causing a big rpm change.

 

That sounds like the best answer yet.

 

I've always filled with the recommended oil also, but this could be the answer we've all been looking for...when the RPMs drop the engine sounds like complete ass

 

That sounds like a great answer to me. Plus, I will be a good candidate to see if this could be it. Let me explain...

I use Mobile1 5W-30 with a quality filter. So oil TYPE is not it. But, I do follow the recommendation of the oil life monitor. Just yesterday I changed my oil. The oil had either been so dirty or so thick on cold days that it crushed the oil filter! Not completely, it was still operational and I wasn't THAT worried about it. It does suggest restricted flow though.

So my plan is this. I'm still going to trust the oil life monitor but I will change the filter (assuming no oil would come spilling out) at 50% life. Then change the oil at the intervals I've been doing with another filter change then also. I know there's the "old schoolers" that change every 3K. I'm not a believer of that, so please save your preaching.

 

I just changed my oil and filter 30 minutes ago just to be SURE it had 5W30 in it. And now that you mention it my filter had 2 pleats not COMPLETELY crushed but definitely deformed. I too do oil and filter at 5000. Although this oil had only a little over 2500 on it. My last change was done by a local oil change place cause I didn't have time before a 1200 mile trip to NY. The tag on the windshield said 5W30 but who REALLY knows for sure what they put in? I had one other bad experience with an oil change place on another trip up north. I told them it needed 5W30 and they said OK. I was watching through the window and the guy started to stick the bulk oil nozzle in the oil fill. I almost broke the door down to get out there to stop him. I asked if they had THAT MUCH call for 5W30 they had it in bulk. 55 gallon barrels. He said no, in fact he had very little call for 5W30 except for the regulars that brought their own oil, but he offered 20W50 was the equivalent and he always used 20W50 instead. Watch what other people do to your car. I usually do but this one almost got by me.

PS
This is the easiest, least messy filter change in the world. Not one drop leaked. Ya gotta love it!

 

It's not saying much at this point but I'll keep you all updated on my experience with this. Right now since changing my oil it hasn't done it. I've heard the ratcheting noise albeit much much quieter but the idle has remained solid.
Just tonight it sat for a good 9 hours, it's 32*F outside and very damp. It fired up without a hitch.

Anyway, I'll keep you all updated and it would be sweet too if we can get members like you Buellfooll to keep us updated too. Maybe together we all can tackle this thing and figure it out.

 

I definitely will report back after 2500 miles.

After this change I am more concerned with the condition of the filter than the engine noise. There were 2 pleats deformed but not fully collapsed. The engine noise got worse after I installed the bolt-ons listed in my sig. And even worse after the Stage kit. I just chalked it up as part of the deal. I will add that the oil was a little darker than I think it should be, considering there's synthetic in it already, but not so bad Ithat I would have changed it for that reason alone.

Next change, which I will do at 2500 miles I am switching to Amsoil products. Their number TWO recommended oil, the Amsoil 5W30 (CLAIMED to be good for a 7500 mile life) and their filter which is a WIX part. Their number ONE recommended oil is their 0W30 with a CLAIMED life of 2500 miles. I'm going to have to make a call to Amsoil about that one, although at $10.50 a quart it is highly unlikely I'll use it. Theoretically the lighter oil will circulate faster to quiet those parts that need oil pressure to operate. THEORETICALLY! I've used Amsoil products for years in everything I own. Truck, motorcycles, lawn mower and even the weed wacker and chainsaw use their 2 cycle oil. My HD Dresser and Buell ran quieter, cooler and went further on a gallon of gas after the change. really! The truck got better mileage and the lawn mower also ran quieter and cooler. I'm not sure if the weed wacker whacked more weeds or the chain saw sawed more wood. I realize this is not a comparisson of synthetic BRANDS. Only a testament to synthetic lubricants. But remember, Amsoil was the pioneer in synthetics.

The filter, as I said, is a WIX piece. Wix makes many of the store brand filters and even some of the branded filters. But those filters are manufactured either to the customers specifications or their price point. In my opinion, WIX filters sold by Amsoil are far superior to anything I have used in the past. The filter I took out had plastic end caps on both ends. Made in China. Chinese junk!

Go to their site and check out all Amsoil products listed for the LNF. There's some good reading there.
http://www.amsoil.com/mygarage/vehic...ROLET+COBALT+Z

I know this sounds like an advertisement for Amsoil. It is NOT. I DON'T sell it. I just use it and like it that much.

I'll report back after my next change which I'll do at 2500 miles. But don't hold your breath cause it's still warm here in FL and I'm using my Fiero/ LS1 whenever I can. It too is on Amsoil and WIX filters along with the transmission. Oh yeah! My stand-by generator too.

Sorry about this long winded post but I wanted to give you a base line for any future reports.

 

I definately have a noise on many cold starts, but its NOT like the ones in the posted videos! I definately experience a "dry" engine sound. when first started, for 3/4 of a second to a full second I sometimes have a loud clacking or grinding sound. my family has 4 other ecotec powered cars in it, and they ALL do this when it is very cold out. at least in my case, I am convinced that the sound I hear comes from the top of the motor being oil starved for the first few revolutions.
My .02

 

Yeah this is totally different. I know what you're referring to though. Tonight it's only about 8 degrees out. Went out from work and it still started without a hitch after the oil change this weekend.

 

While the OIL Life monitor is nice and I use it as a reference I still change my oil at 50% because I'm retentive. I use Mobil1 5W30 because thats the oil the motor was developed on. And because its what we use on a ZR1 Engine. Theres thousands of miles of dyno durability on that oil in GM engines. I also use Bosch filters.

Nothing wrong with amsoil though. Its just awfull spendy.

I am a GM engineer, My opinions are my own.

 

Castol Edge 5W-30 in my car right now. Was using M1 0W-30. Both meet or exceed GM 4718M (IIRC That is the standard for the LNF)

 

Hi All,

Well I have been having this problem too for the last month or so. Every morning when I start the car to go to work ( it is about 30-40 degrees outside) I get that nasty grinding sound for a sec or two. After two weeks of hearing it I decided to take it in to the dealer (which im using a new dealer now cuz my old one sucked, the new dealer seems much more professional and knowledgeable). The first few times they tried to start the car they did not hear the sound but this morning they did hear it! They told me that there is a bulletin out for the cam phaser. I immediately thought of what Gettinausernamesucks said a few posts above mine. For the last two oil changes I used Royal Purple 10W-40...not the best idea I guess. I am rather certain that caused the problem. I did change the oil back to M1 5W-30 before I took it into the shop and I will continue to use that oil for the life of the car. The dealer has the car today and I should have it back tomorrow. They are replacing my cam phaser as i type this. I will report back after a week or so and let you guys know the results, if the grinding comes back or not but I am pretty confident this will fix it! :

John

 

Just heard back from dealer...they decided not to replace the cam phaser because when they looked at it they said it look fine. guess i got excited too quick. They want to keep it one more day to listen to it again...I will let you guys know the results...