[Justin Dent]

Hi guys,

I have a 2016 Colorado 2wd z71 with 3700km. I purchased the truck new 6 months ago. I am having an issue where I notice what sounds like a metallic spinning noise or maybe a metallic bird-like noise (hard to describe). It only occurs when accelerating around 3rd gear. I hear the noise right around when i get into 3rd and then once I hit cruising speed I don't hear it. It is a very brief sound too, I hear it about 3 times in a span of a few seconds and then its gone. It seems to happen more often when I accelerate fast (not flooring it or anything). I have tried numerous times to pin point if it is coming from the front or back but cannot figure it out. I tend to hear the noise most when going over a bridge because sound is amplified. I have to turn my radio off and listen pretty closely to hear it on normal roads but if I listen for it I hear it almost every time. I had a 2011 Canyon that I'm pretty sure had the same or similar noise. I have had the noise since I bought the truck and just assumed it was a normal noise since my old Canyon had a similar noise. I am not sure if this is normal for pickups or not since I have only owned pickups for less than 2 years. Since it is a new truck I would love to not have any strange noises to worry about. I will probably take it in to the dealer eventually but after my experience with them with my last truck (rear diff went out twice and they couldn't seem to fix it properly without it whining) I am leary to take it in. I am not super worried at this point because I have 6.5 years of warranty left. Does anyone have any idea what it could be or have a similar issue? Thanks!

 

[csufsnwbrdr]

I had similar but mine's 4wd. Wound up blowing the front differential. Could only get it to do it once the trans was up over about 140*F in cold conditions (going snowboarding/winter/etc.) Sounded like a power steering pump that went bad and was usually only at parking lot speeds (under 10mph) but the last time it did it when I'm pretty sure it failed (thankfully didn't go off like a bomb or leave me stranded) I was at 40mph. It's usually drown out after about 15-20mph usually. There were also two seals at the transfer case they changed out. Might not help you out much, but I'd have the dealer take a look at the back differential at an oil change or something.

 

[Justin Dent]

Interesting, I've read others with something similar with 4wd but not much on 2wd. I think my next step is to try and rev the engine in neutral to see if it does it. I really wish I could figure out which end of the vehicle it's coming from but I've even tried driving with my head out the window but no luck yet. I'd like a little more information to go on before asking the dealer.

 

[spoonman]

Give a look at the heat shields on the truck yet?

I know theres one above the upper control arms that gave me a rattle for a while while accelerating but I got rid of it by bending it back a little.

 

[Justin Dent]

Spoonman I have not checked the heatshields yet, I will add that to my list do things to check. Did your heatshield only rattle in a certain gear while accelerating or the whole time your accelerating?

 

[Justin Dent]

SO I tested a few things out today.

1. The noise does not occur when revving in neutral.

2. I found 2 small heats shield both near the front suspension that are pretty loose but I don't know if they were designed that way. The passenger side one seems to make more of a metallic sound when moved than the drivers side heat shield. I took a couple pictures of it and will upload a video of me wiggling it later.

Should these heat shields be loose? They appear to only be fastened on in one spot but it's hard to see all around it.

Here is a video of it:

https://youtu.be/H3SKd0poNvo

 

[GeorgeT451]

Should these heat shields be loose? They appear to only be fastened on in one spot but it's hard to see all around it.

I wouldn't think they should be loose. I have had them loose on other vehicles and they can make a lot of noise when rubbing against other metal parts.

 

[Justin Dent]

Just went with my brother for a drive and had him try and listen for the noise with his head out the window to determine where it's coming from. He thinks it's coming from the front but can't be 100% certain. The more I hear it the more it sounds like the heat shield rattling. This is the heat shield you can see in the wheel well near the top. Is there some kind of rubber or something I can stick underneath it so it doesn't contact metal to metal? I would bend it back but it seems too loose for that to work.

 

[Chuck_B]

Give your fender a gentle bump between the bottom of the windshield pillar and the center of the wheel arch. See if that is the rattle.
There is a fender to unibody spacer just behind the center of the wheel arch. The easiest way to access this is to pull the tire and fender liner. Squirting a little RTV between the inner structure and spacer fixes it if this is the problem. The spacer to fender interface will be ok as this side is bonded with foam adhesive.

 

[BngnZ]

I have the same noise you are describing from front end underside. I hear it in morning as I coast out of garage and then next to concrete dividers at 40 mph or below when in high gear/ low RPM when depressing throttle before it downshifts. Also does not do it while in neutral or in park reving engine. My truck is a 2016 z71 v6 4x4 CCSB with 33k miles on the ODO. It's been doing this for past 10 k maybe. I have it in shop now and this issue is on the list along with the speaker rattle on pass side, Seam on drivers side seat starting to rip and the shudder at stop light and while keeping speed at 70 mph on flat surface on interstate. The shudder at stop light also goes away when i put it in neutral or park and doesn't affect RPM either. Hopefully one of these gets fixed.

One other thing is that since new after I shutoff engine and wait from 15 sec to one min later i get a Knock Knock Knock coming from between cab and bed underneath. This does this all the time. Anyone else ever hear this?

 

[Justin Dent]

Thanks bngnz let me know what the shop says about the noise. I have determined that it is not from my heatshields as I managed to keep them from flapping but the noise is still there. I am starting to think it is probably drivetrain related but I don't know forsure. I will take it in to the dealership in the near future. I'll have to check if I hear that knock noise you have after you shut it off.

 

[csufsnwbrdr]

I have the same noise you are describing from front end underside. I hear it in morning as I coast out of garage and then next to concrete dividers at 40 mph or below when in high gear/ low RPM when depressing throttle before it downshifts. Also does not do it while in neutral or in park reving engine. My truck is a 2016 z71 v6 4x4 CCSB with 33k miles on the ODO. It's been doing this for past 10 k maybe. I have it in shop now and this issue is on the list along with the speaker rattle on pass side, Seam on drivers side seat starting to rip and the shudder at stop light and while keeping speed at 70 mph on flat surface on interstate. The shudder at stop light also goes away when i put it in neutral or park and doesn't affect RPM either. Hopefully one of these gets fixed.

One other thing is that since new after I shutoff engine and wait from 15 sec to one min later i get a Knock Knock Knock coming from between cab and bed underneath. This does this all the time. Anyone else ever hear this?

That knock noise if it's what I'm thinking of, is normal. I asked about it on my '06 Silverado that did the same when I had it and I think they told me it had something to do with the fuel pump. Anyway, it was within 30 seconds of shutting either off and was just click-click and like an electrical spin-down if you listened close. Seems pretty typical of GM.

I'd be curious to see what they find on your passenger speaker rattle. I've had mine in I can't tell you how many times for various rattles from the drivers front speaker to the passenger dash to both front door panels. Finally got them to tear into the dash and they found screws at the pillars on both sides that were about a turn-and-a-half loose. Still have the door panels and that drivers speaker that still rattle intermittently though even after they "fixed it". Only way I could get the driver's side speaker to stop was to wedge my fingers between the windshield and speaker grill then it would go away even tried dense foam weather stripping!

 

[Justin Dent]

I have an appointment at the dealership this morning so I will update here if they find anything.

 

[Justin Dent]

The dealership called me and said they pinpointed the noise to the engine area. They believe it is bad lifters which have a service bulletin out. Unfortunately their engine guy is on vacation until next week so I got the truck back and will be going in next week to get this fixed. The reason I bought a new truck is to avoid having to repair things all the time.... so much for that.

 

[csufsnwbrdr]

The dealership called me and said they pinpointed the noise to the engine area. They believe it is bad lifters which have a service bulletin out. Unfortunately their engine guy is on vacation until next week so I got the truck back and will be going in next week to get this fixed. The reason I bought a new truck is to avoid having to repair things all the time.... so much for that.

I feel your pain! That's why I got rid of my 2006 Silverado as well, was tired of it $100 and $500-ing me to death and my 2016 hasn't been much better!

 

[BngnZ]

The dealership called me and said they pinpointed the noise to the engine area. They believe it is bad lifters which have a service bulletin out. Unfortunately their engine guy is on vacation until next week so I got the truck back and will be going in next week to get this fixed. The reason I bought a new truck is to avoid having to repair things all the time.... so much for that.

wow that was quick. They have had my truck since Sat and I haven't received an update as of yet. Been driving a loaner 17 silverado LT z71. That thing shifts bad at times like my truck does. I have also been lurking over on tacomaworld and it seems they have just as many if not a few more issues than we do though on the 3rd gens.

 

[BngnZ]

Finally got my truck back Friday. It ended up being exhaust after all. Had a weld break loose at rear Catalytic converter and rattle around inside. They replaced the whole y pipe assembly at rear. Part # 23343108

 

[Justin Dent]

So it's been a few weeks but I have resolved my issue. Originally the dealership told me that they thought it was the lifters but the engine guy was on vacation so they didn't know forsure. I brought it in again a week later so he could look at it and he said it couldn't be the lifters because if it was it would make the noise all the time.

The technician thought it could be slight spark knock so he hooked his computer up to my truck and we drove around. Whenever the noise was present the computer showed about 1 to 2 degrees of spark knock for a couple seconds which the technician said was within normal limits. The computer also detected spark knock in cylinder one for about one second. The technician said it seemed normal but they forwarded the data to GM along with my issue so they can look into it. I asked a couple technicians at the dealershio about trying higher octane gas to see if that fixes it and they said to give it a shot.

I had been planning on trying high octane gas for a while after hearing about some people on here having good results with it. I filled up with a tank of Ultra 94 here in Ontario and right away the metallic noise went away. I also noticed no more sluggishness in low gears and I haven't felt it shift hard at all since. I think the 94 octane has made a big difference in my enjoyment of this truck and I will be buying premium gas from now on. To me an extra $10 a tank is worth it if it means I enjoy driving my truck more. I'd suggest everyone with one of the twins try a full tank of premium and see if you notice a difference.

 

[Paul Bassel]

Yet another reason to own a diesel! ?

 

[boombots]

Mine has spark knock like a bitch on regular gas. The cheaper option than the high test fuel is the bottles of octane booster. You can snag a case of 12 for 30 bucks on Amazon. That boosts it enough to kill the issue.

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