2011 5.3L v8 startup noise

[Chillywilly]

Hi, Bought this preowned 2011 with only 32000 miles. At random, both with hot and cold starts, at startup when the engine turns over there is a misfire or slapping noise. Happens several times a week and the dealer says thats 'normal'. Really ???. Any guidance on what I should be asking they do to address this. Thanks in advance.

 

[Relic49]

Maybe try another dealer or a reputable auto repair shop for a second opinion.
Good luck.

 

[poncho62]

Probably piston slap........The pistons get slightly worn and rock a little bit in the cylinders until they heat up and expand. I have heard of this after 20 K on GM engines.

 

[Chillywilly]

Does the noise from piston slap continue for a bit after startup? Reason I say that is this noise is as the engine turns over only, doesn't continue when running Almost sounds like a pop/swoosh when I turn the key over....a bit difficult to describe

 

[Chillywilly]

This noise at startup is now happening at random, both on cold starts and hot starts. No error codes coming up and the dealer says they can't replicate it. Frustrating.

 

[Chillywilly]

...amperage surge from the battery....which sounds off via the sound system on startup. Looking for more on this as the dealer says this is quite common and no problems. Anyone with first hand knowledge is appreciated.

 

[Bill325]

It may well be something like a signal coming from the sound system. I don't know . However, be sure the noise isn't coming from the starter motor . Loose starter motor bolts can cause start up sounds.