Loud Tapping/Clicking on Cold starts

Obscenejesster · November 15, 2017

Sounds electrical to me. I'm not a mechanic but a lifter tick wouldn't be so high pitched.

Sent from my LG-H932 using Tapatalk

hirdlej · November 15, 2017

I suspect it's coming from the high pressure pump. Have you tried starting it and putting a hose near the back of the intake manifold while putting the other in your ear to try isolating it? Again, mine went away after putting a few more thousand miles on it.

grizz_wi · November 17, 2017

On 11/14/2017 at 10:06 PM, hirdlej said:

I suspect it's coming from the high pressure pump. Have you tried starting it and putting a hose near the back of the intake manifold while putting the other in your ear to try isolating it? Again, mine went away after putting a few more thousand miles on it.

No i havent sounds like its coming driver side of engine, regardless a new vehicle shouldnt make these sounds and dealer said they would call me today, imagine that they didnt.

M B · November 17, 2017

Hope this sheds some light on what looks to be a common problem.

I took my 5.3 into the dealer today with 700 miles on it to be told by the service manager FIVE TIMES before I could get half way through describing the issue. "They all do that. It's normal!" (Useless A HOLE parroting excuses). The issue IS the truck has a HARD miss at low idle. You can watch the engine jerk as it happens, and feel the truck stutter sitting in it. Sometimes it also taps EXACTLY like a sticking lifter I had in the old 5.7L Tahoe I traded in. LOL!

It also makes a very short (one second) rattling noise on cold start. Sounds like a loose exhaust bracket.

After getting the call to pick it up. Mr. "I Can Spit Out a BS Excuse Faster Than Lightning for ANYTHING" service manager says (and their documentation states as well). They "were unable to repeat any problems at this time". As I'm leaving I run into a mechanic by GREAT LUCK, and he mentions "Did they at least tell you what it is? Mine does the exact same thing and it drives me nuts to! It's the Active Fuel Managment shutting off one cylinder at a time to save fuel at idle. You can watch it happening on our diagnostic computer.". O.O

I'm blown away that I was lucky enough to run into him!!! AND they didn't try to blame the CAI I installed (problem was there before the intake)!!!

Not sure what the rattling noise is at start up... But I was planning to start the GM buy back procedure until I ran into that mechanic!

Obscenejesster · November 17, 2017

Hope this sheds some light on what looks to be a common problem.

I took my 5.3 into the dealer today with 700 miles on it to be told by the service manager FIVE TIMES before I could get half way through describing the issue. "They all do that. It's normal!" (Useless A HOLE parroting excuses). The issue IS the truck has a HARD miss at low idle. You can watch the engine jerk as it happens, and feel the truck stutter sitting in it. Sometimes it also taps EXACTLY like a sticking lifter I had in the old 5.7L Tahoe I traded in. LOL!

It also makes a very short (one second) rattling noise on cold start. Sounds like a loose exhaust bracket.

After getting the call to pick it up. Mr. "I Can Spit Out a BS Excuse Faster Than Lightning for ANYTHING" service manager says (and their documentation states as well). They "were unable to repeat any problems at this time". As I'm leaving I run into a mechanic by GREAT LUCK, and he mentions "Did they at least tell you what it is? Mine does the exact same thing and it drives me nuts to! It's the Active Fuel Managment shutting off one cylinder at a time to save fuel at idle. You can watch it happening on our diagnostic computer.". O.O

I'm blown away that I was lucky enough to run into him!!! AND they didn't try to blame the CAI I installed (problem was there before the intake)!!!

Not sure what the rattling noise is at start up... But I was planning to start the GM buy back procedure until I ran into that mechanic!

Please let me know what you found in regards to the quick rattle at start up. I suspect there to be a loose piece of hardware somewhere in the exhaust.

Sent from my LG-H932 using Tapatalk

grizz_wi · November 21, 2017

In case anyone cares, dropped it off yet again, apparently a engineer from GM is coming to look at it tomorrow, I'll let you know what they find.

DustyC · November 21, 2017

Yes, please post what you find. My truck ('17 2k miles) is noisy on start up too.

Thanks!

grizz_wi · November 22, 2017

Apparently I need to wait for GM to call with their findings, I am getting real sick of dropping it off and putting my shit into a loaner. Its the 3rd freaking time.

2017SierraSLT · November 23, 2017

The oil pump design has changed from a gerotor gear type pump to a two speed vane type pump for fuel economy reasons. At temperatures of 32°F (0°C) or colder, when the engine has been sitting for a few hours it is possible to have air enter the pump through normal oil drainback. Upon startup the owner may hear a short Rrrrp or Rasp coming from the front of the engine. It is most often heard during a remote start. There is nothing wrong with the oil pump or oil system. No repairs should be attempted for this condition.

grizz_wi · November 29, 2017

On 11/23/2017 at 1:13 PM, 2017SierraSLT said:

The oil pump design has changed from a gerotor gear type pump to a two speed vane type pump for fuel economy reasons. At temperatures of 32°F (0°C) or colder, when the engine has been sitting for a few hours it is possible to have air enter the pump through normal oil drainback. Upon startup the owner may hear a short Rrrrp or Rasp coming from the front of the engine. It is most often heard during a remote start. There is nothing wrong with the oil pump or oil system. No repairs should be attempted for this condition.

Meh my 2016 didnt do it, my bros 17 doesnt do it and my several 2018 loaners dont do it. Pretty embarrassing for a noise that can be heard in my kitchen when started.

They called back and said they put the wrong vaccuum pump on? Lol something about it needs to be a steel fitting and not a brass one, per the "engineer" Dropping it off tomorrow if the parts come in.

hirdlej · November 29, 2017

This will be interesting. Please let us know!

hirdlej · December 5, 2017

On ‎11‎/‎22‎/‎2017 at 12:16 PM, grizz_wi said:

Apparently I need to wait for GM to call with their findings, I am getting real sick of dropping it off and putting my shit into a loaner. Its the 3rd freaking time.

Did they give you any timeline as to when you can expect to hear from them? I started my truck this weekend (it's in storage for the winter) and I listened for the noise again. It's still there but very faint. It's about every 5 engine revolutions or so and it's only at idle I hear it. It's like blub blub blub blub *thud*, blub blub blub blub *thud*. Sorry, that's the best way I can communicate over the internet. Any update on your end yet?

grizz_wi · December 5, 2017

1 hour ago, hirdlej said:

Did they give you any timeline as to when you can expect to hear from them? I started my truck this weekend (it's in storage for the winter) and I listened for the noise again. It's still there but very faint. It's about every 5 engine revolutions or so and it's only at idle I hear it. It's like blub blub blub blub *thud*, blub blub blub blub *thud*. Sorry, that's the best way I can communicate over the internet. Any update on your end yet?

I dropped it off again they have the new vacuum pump with the correct fittings and will be installing it. Hopefully have a call back tomorrow.

hirdlej · December 5, 2017

Sounds good. Let us know how it turns out.

grizz_wi · December 6, 2017

Yea this dealer can go screw itself, after 4 vaccuum pumps I am now being told its normal because they cant figure out where the noise is coming from. Its obviously not the damn vaccuum pump if 4 of them did it! I'll upload my paperwork when I get it in the mail, but I am not done fighting this. Heres a link to my entire video on youtube I just cant see this noise being normal.