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2007 Av and ticking noise at engine start

CruisinCO

New Member
Joined
Oct 29, 2007
Messages
2
Hi all, recently bought my 2007 Av and just joined this great group here yesterday. Anyhow, when I start my car I swear I hear a ticking-like sound from under the hood. It seems to go away after I drive for a bit. I asked the dealer if I had a loose belt or something worse and they swear they can't hear anything. They said they ran computer tests on the engine and it all came back fine.
Anyone else run into this?
 
I'm guessing you're in Colorado.  Thus, it's cold :)

You may be hearing piston slap.  Search here, and on the web, to understand it.  Not really anything of concern, just an inherent thing in this engine.
 
I suppose if you live in Florida, mid-low 70's could pass for cold.
 
  nothing to be real worried about.  been a problem for GM a while now.  there is a TSB out on it.  there is plenty of info on it throughout the forum.
 
ltxi said:
I suppose if you live in Florida, mid-low 70's could pass for cold.

Hey, it's low 80's and VERY breezy here today.  May need a long-sleeved shirt!
 
could be heat shields too?
 
Yeah, but I'd bet on the piston slap.
 
Thanks for the replies!! I do a search on piston slap and see what the story is. It just seems odd to me that for this much money they can't get rid of a tick noise. I guess I'll have to learn to deal with it.
 
In my wife's 07 Tahoe we hear the same thing, one of the service repair guys suggested we switch to Synthetic oil.  Something about coating the piston with oil (because sitting all the oil drains back to the pan) and it's not as loud as before.  The sound almost sounds like a lifter sticking?
 
The fuel injectors have been known to ?tick? upon cold start also.

 
CruisinCO said:
Thanks for the replies!! I do a search on piston slap and see what the story is.  It just seems odd to me that for this much money they can't get rid of a tick noise.  I guess I'll have to learn to deal with it.

It should seem odd. Piston slap was universally considered a bad thing in engines until GM apparently unintentionally "normalized" the "feature" with the 5.3L in 1999. A lot of very cranky and concerned consumers for the first 2 - 3 years. It doesn't seem to have affected longevity, though, and is now seen as normal. Varies from vehicle to vehicle and is more evident when colder. Goes away after warm up.
 
Got the tic also, during cooler weather and is most noticeable if you put your foot into the accelerator more than normal during the first minute or so of engine warm-up.

Solution: Keep my foot out of it and let it warm up a bit longer.  Then she purrs like a kitten.
 
sk8deck said:
mine tics, but before its starts using the remote. Its sounds more like a eletronic tic.

Quickly get out of your AV and run away.  It could be a BOMB!
 
  I have an 07 AV that i got back in July last year.  I experienced the same thing around the winter months and I live in AZ so it doesn't get quite as cold here.  Its almost like a pinging sound mostly heard during acceleration. I tried to troubleshoot the problem myself since the dealership couldn't hear anything.  I tried using fuel injector cleaner and looking for loose components.  It did go away completely tho when I switched my oil to the Mobile 1 full synthetic. after about 2,000 miles of running this oil it went away noise went away.  Hope this helps...also if anyone has an 07 AV or Tahoe do you know how to remove the interior trim pieces?
 
ltxi said:
It should seem odd. Piston slap was universally considered a bad thing in engines until GM apparently unintentionally "normalized" the "feature" with the 5.3L in 1999. A lot of very cranky and concerned consumers for the first 2 - 3 years. It doesn't seem to have affected longevity, though, and is now seen as normal. Varies from vehicle to vehicle and is more evident when colder. Goes away after warm up.

Piston slap started with GM before the 5.3, and even before the LS1 in '97.  Started really with the LT1 in '92, when the pistons began being coated.
 
if it makes y'all feel any better I'm the original owner of a 2001 5.3 liter.
Had the piston slap noise from day one.
After 125,000 miles ...the noise is no worse...no problems...
 
my 6. 0 started doing the same thing. i run mobil 1 5W30. noticed it ticking on cold starts about 5000 miles into my first oil change. toped of the oil (added 1/4 quart) to get it right on the full mark and now it doesn't tick.   ??? o well worked for me. might give that a try. (i go by the DIC on intervels. (y))
 
Derek LS6 said:
my 6. 0 started doing the same thing. ?i run mobil 1 5W30. ?noticed it ticking on cold starts about 5000 miles into my first oil change. ?toped of the oil (added 1/4 quart) to get it right on the full mark and now it doesn't tick. ? ??? o well worked for me. ?might give that a try. ?(i go by the DIC on intervels. ?(y))

Go to www.pistonslap.com to see it that is what you are hearing.  In my '07, it's a lifter that related to positioning of the cam at the high-lobe on piston 1 or 4 valves at engine shut-down.  After sitting overnight, the oil is bled off creating slop in the valve train on a cold start.  Mine takes a minute or longer to build oil pressure back to within design clearance or required valve-lash.  Pistons 1 and 4 on the driver's side (6 and 7 on the passenger's side) that are controlled by the AFM system that bleed off hydraulic pressure to collapse or de-activate the lifter when it shifts to 4 cylinders operations.  In other words, those 4 cylinder's valves no longer open during a 4 cylinder operation.

Several owners have reported this problem including "yours truly" however none to my knowledge, have not been able to get their dealer to respond to the issue.  While some say it's just an initial cold start noise that is harmless, I say "B.S.".....a tap like I have will eventually damage the affected rocker arm or valve top or both well beyond the design tolerances.

As an experienced engine builder, I have conducted an experiment with manually turning the engine to collapse the lifters and have reproduced the tap each time.  I have retained an independent, certifed mechanic who is following this same procedure.  I expect a written report as evidence in forcing the dealer to make the necessary repairs.  If they balk again....we go to court.
 
Rocky07 said:
Go to www.pistonslap.com to see it that is what you are hearing.? In my '07, it's a lifter that related to positioning of the cam at the high-lobe on piston 1 or 4 valves at engine shut-down.? After sitting overnight, the oil is bled off creating slop in the valve train on a cold start.? Mine takes a minute or longer to build oil pressure back to within design clearance or required valve-lash.? Pistons 1 and 4 on the driver's side (6 and 7 on the passenger's side) that are controlled by the AFM system that bleed off hydraulic pressure to collapse or de-activate the lifter when it shifts to 4 cylinders operations.? In other words, those 4 cylinder's valves no longer open during a 4 cylinder operation.

Several owners have reported this problem including "yours truly" however none to my knowledge, have not been able to get their dealer to respond to the issue.? While some say it's just an initial cold start noise that is harmless, I say "B.S.".....a tap like I have will eventually damage the affected rocker arm or valve top or both well beyond the design tolerances.

As an experienced engine builder, I have conducted an experiment with manually turning the engine to collapse the lifters and have reproduced the tap each time.? I have retained an independent, certifed mechanic who is following this same procedure.? I expect a written report as evidence in forcing the dealer to make the necessary repairs.? If they balk again....we go to court.

Rocky, I posted in a reply to the other thread on this topic that my dealer told me that unless the ticking lasted longer than a minute there was nothing they could do about it.  The implication there was that anything over a minute was a problem.  Unfortunately I don't have anything in writing to that effect though.  Perhaps there is a TSB on it.
 
Rocky07 said:
Go to www.pistonslap.com to see it that is what you are hearing.  In my '07, it's a lifter that related to positioning of the cam at the high-lobe on piston 1 or 4 valves at engine shut-down.  After sitting overnight, the oil is bled off creating slop in the valve train on a cold start.  Mine takes a minute or longer to build oil pressure back to within design clearance or required valve-lash.  Pistons 1 and 4 on the driver's side (6 and 7 on the passenger's side) that are controlled by the AFM system that bleed off hydraulic pressure to collapse or de-activate the lifter when it shifts to 4 cylinders operations.  In other words, those 4 cylinder's valves no longer open during a 4 cylinder operation.

Several owners have reported this problem including "yours truly" however none to my knowledge, have not been able to get their dealer to respond to the issue.  While some say it's just an initial cold start noise that is harmless, I say "B.S.".....a tap like I have will eventually damage the affected rocker arm or valve top or both well beyond the design tolerances.

As an experienced engine builder, I have conducted an experiment with manually turning the engine to collapse the lifters and have reproduced the tap each time.  I have retained an independent, certifed mechanic who is following this same procedure.  I expect a written report as evidence in forcing the dealer to make the necessary repairs.  If they balk again....we go to court.

Probably stupid question since AFM doesn't kick in until the motor is up to full operating temp, but do you suppose turning off AFM might help the problem? Maybe a residual where it was mechanically left on shut down?
 
EricM....I remember seeing your posting about the dealer discussion.  Personnally, one minute ticking is entirely too long regardless of the source of the problem.  But, I played a recording of my tick to my dealer who first said,  "How do I know that is your vehicle?"  That comment would piss off the Pope, but, I see it differently.  Those are defensive comment by someone who has his "gonads" in a vise.....and I'm squeezing them hard.  And, that is obviously a comment from someone who has been screwed by a customer or GM or both in repairs made.  So, given that attitude, I have decided to get my case in "legal hands" with credible evidence that will force some action.

Ixti....that is a good point and certainly not a stupid question.  But, since all 8 cylinders are running at engine shutdown, fully pumped up with oil pressure, the resulting tick on a cold start (and present delimma) occurs when the affected valve stops up on the cam high-point.  Then the defective lifter slowly releases the hydraulic pressure over time (generally over night) resulting in a excessive valve lash when started.  So, maybe to answer your question, I'm not sure that disengaging the AFM would change anything.  That is, if I even knew how to do it.

Good question though....got me to thinking.... (y)
 
I had ticks once.
Solution:  Pour lighter fluid over the infected area.  Light it on fire.  As the little bastards jump onto your thigh, stab 'em with an ice pick !!!

Rids you of ticks.


Trophyman
 

Didn't know for certain if system was always in full V8 mode when shut off when off the throttle. But thinking about it, I would suppose it must be because AFM only operates above some minimum vehicle speed (?). Weak lifter bleed down certainly isn't anything new, but I would have to believe that the complexity introduced by AFM into a part that used to be relatively simple could compound the problem immensely.

The Diablosport Predator  handheld gives one the capability to turn off AFM. As I understand from anecdotal evidence, mileage doesn't suffer noticeably and it cleans up some significant driveability issues that sometimes occur when performance tuning the PCM.

My solution is to bring back solid lifters and I'll just adjust the lash every xxK miles.  :cool:

Trophyman..........I've used that method with great success. Unfortunately, I'd been drinking heavily at the time and didn't fully appreciate the consequences. Since giving up drinking was out of the question, I moved to Colorado where we don't have ticks in order to save my other leg.  (y)


 
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