Valve Tick, Muffler Baffle Rattle TSB Work ...

[2010 2SS RS]

So I just brought in my 2010 L99 *(under warranty) to my local chevy dealer for the muffler baffle metallic rattle noise im having at low rpms and the cold crank start up valve tick problem. The shop foreman went for a ride along and confirmed my above stated exhaust concern, said they would take care of it no problem. I'll report back on this post with what was replaced as soon as I get word from em.

Now on to the valve tick concern. I told them I have a valve tick on cold start ups and that it doesnt sound like normal valve or fuel injector chatter. In respone I was told that this noise is normal that its indeed fuel pump and fuel injector chatter, that my car has a very high pressure fuel system and that the tick is a noise that the fuel pump makes while regulating fuel pressure when its first started. So I said come on really a high presure fuel system... my 04 Mach has like 10:1 comp ratio with VVT, pretty high presure and its chatters nowhere near as load as this thing and its packed with all kinds a noise reducing insulation... ?? NO response so i proceeded to tell them that I have a GM TSB-(pdf) bulletin on my phone about excessive valve tick chatter on cold crank start ups for my model explaining how and why this might happen and how to test for it
*(instruction for the tech to determine the duration of the tick to see if Chevy will replace the lifters or not)
When confronted with this they said theres another bulletin attached to that bulletin explaining that's it what they just told me it was and i was mislead.... What he didn't know is that I have that exact bulletin *thanks to my GM friend that they were talking about and it was for the V6 VVT engines only but I didn't let them know this at that point because be4 I could say anything they offered to take me to the back shop to talk to thier top tech about my concern. The top tech quickly confirmed that I might have a valid issue if what i say is the case, that the L99 with the dang AFM is known to occasionally have this problem, which I knew thanks to camaro5, we chated shortly about new cam kits blah blah blah and well he said that they will need the car overnight to look into it.

So long story short they have my car. They are repairing the exhaust for sure they just need to isolate the problem to see if they are replacing just some or all of the exhaust component i figure. I will report on what exactly was done as soon as I hear from them about it.

Now I will also report back about the valve tick issue too. I hope all goes smooth, my minds playing trick on me and I have no valve problems because I don't want my motor to get pulled apart unless its for internal upgrades, not stock swap out :( but if I do, which I feel I might, I hope I don't get any more excuses because I don't wanna have to pull out the other bulletin a buddy gave mean and call them out on trying to BS me with a bulletin thats meant for the V6 with VVT.

Anyways i know a lot of people r having these same problems and i thought i would share my personal experance in hopes that it might help someone in resolving there own similar problem in the future!! Below ive attached a link to the downloadable TSB about the valve tick i got on Camaro5 and a pic of the TSB my GM friend set me
Start Up Lifter Tick Noise After Engine Has Been Off for 2 Hours or More - AFM Engines.pdf

[DieselDork]

Hey there,

I'm interested to know how you made out with the "clicking/ticking" sound at start-up. Mine does the same thing. 2010 L99 with just under 10k miles. I bought the car with 6k miles. It started doing it around 7k miles. I changed the oil (mobil1 again), and it went away until about 9k miles.

only does it on a cold start in the morning. won't usually do it after work.

It REALLY bothers me, but I have just not started doing research.

I'd love to hear what you found out.

Thanks!
Andy

[russofnj]

Hello, I have the same 2010 silver grey v8 automatic. I get a vibration between 1200 & 1800 rpms which goes away if I hit the gas. I was told that it was the exhaust and was perfectly normal. Much too annoying to be normal. Almost feels like a loss of power. Is this the same issue and what did you do about it. Thanks, Russ

[3BCT4ID]

i have the same issue with mine

[SS King]

Originally Posted by russofnj

Hello, I have the same 2010 silver grey v8 automatic. I get a vibration between 1200 & 1800 rpms which goes away if I hit the gas. I was told that it was the exhaust and was perfectly normal. Much too annoying to be normal. Almost feels like a loss of power. Is this the same issue and what did you do about it. Thanks, Russ

more then likely its your AFM kicking in

[Rock-It Man]

Only the V6 has high pressure injectors. Not applicable to the L99.

The ticking issue on the L99 is related to the lifters. If you want it fixed, the heads come off.

Mine happens only occasionally, so I'm leaving it alone so far.

[dannykay]

Agreed.....def sounds like the AFM kicking in...