Squealing noise silverado 2014 when she is shut down

[Rush78]

I have a 2014 1500 silverado 5.3. When the truck is off there was been a squealing noise coming from under the hood, it's there for a long time after too. Say 5 hours later or more. It will make the noise and stop then do it again. Kind of reminds me of the old dial up modems. I have never heard it in any of my older trucks and have no idea what it is. My truck is about a year old and has less then 12000 on it. Was wondering if this is normal with the new models and what it is. The first time i ever heard it was right after the annual inspection. I took her home and gave her a wash and wax. Never thought much of it at the time because i had just gotten her back and figured if it was something wrong that they would have picked up on it. Any help would be appreciated, even to kill my own curiosity now.

[The Zip]

Deleted, kinda missed the part where the truck was OFF.

[Rush78]

Lol...no worries. I can't explain it, but I do have a video with the noise and the truck isn't running. It was sitting up roughly 5 hours when i noticed it this time. I was wondering if maybe it could be the computer board or something. Wish i could post the video.

[Rush78]

Never mind won't download

[Jsdirt]

Yeah I can never get vids to work on this site either - I have to upload then link them to Photobucket.

 

Guaranteed it's probably something electronic doing this. Nothing mechanical would, with the engine off. I've heard laminates in a transformer make a similar sound when stepping down 120v to 6v, or 12v, or whatever the transformer was. Doubt there's anything like that in the truck, aside from the ignition coils. Could be stray voltage bypassing the switch, or shorting to one or more of the coils?

 

I'm really reaching here - could be anything, really ...

[Rush78]

I know a lot to take into consideration. Like I just got her inspected. Plus there's no issues with the truck other than the noise, and i am not around to listen to it long enough to get on my nerves. .lol.

 

Here is the video

 

Watch "Squealing noise silverado" on YouTube

 

 

see if this works

[Jsdirt]

GM ... I really hope you guys watch this one. WTF are you guys doing over there???

 

 

Wow is that odd! Trapped aliens in the valve covers!

 

It definitely sounds louder on the passenger side. Almost sounded like it was coming from the alternator. My theory is it's either that or the ignition coils, getting a voltage command from the computer that shouldn't be there with the key off. Wow is that strange!!

 

Gotta love modern vehicles!

[The Zip]

Heard it, I wouldn't be comfortable with that sound. Since you first noticed this after your annual inspection, it's fair to say the sound may be connected to something they did or didn't do. Was this a state DMV inspection or just one of your annual inspections at a local garage? What type of service was done for this annual inspection? I agree with Jsdirt, electrical. So, disconnect your battery for about 10 minutes or so (no logic for 10 minutes) and see if that resets something. One other thing, how old is you battery?

[Rush78]

I was thinking electrical forsure. She was inspected at Hickmans Motors for her first annual. I am not sure on the date on the battery, have to check that one when i get a chance. I am assuming sence the truck is not even a year old it can't be to old itself. She has all her warranty so I ll take her back to the dealer and see if they can explain it going on. The only problem is that it might happen and it might not. Don't always hear it and you have to be listening where she is not as load with the hood closed.

[00Silverado4x4]

Power steering pump (being electric now) trying to turn?

 

Grabbing at straws. Don't know that much about the 2014+ trucks.

[Jsdirt]

Whatever it is, it sounds like it's pulse width modulated current, the way it slowly comes on, and slowly goes away - almost like it's being manually controlled by a rheostat.

 

Will be interesting to see what it really is! My money is on everyone at the dealership being stumped too. It's amazing how complex vehicles have become, when their own factory engineers can't even figure out a problem. This happened with a neighbor's Ecoboost that shut down without warning, usually when you needed the power the most ... like passing another vehicle. He had to sue Ford to get them to give him a V8 version of the Ecoboost. Still had to pay $3K too.

[Rush78]

Was talking to the guys at the dealership apparently I not the only one who has this problem, but the first to have it on video. They are all stumped, everyone including the mechanics after i Showed them the video. They asked me to email it to them but it was to big a file and i never had my usb for the phone. So i gave them the link them the link. The head of service has taken everything and looking into. Asked about leaving the truck but like i figured, it makes no sense because you can't tell when it's going to happen.

[The Zip]

Start with the Hickam Motors service invoice, whatever they did had a negative impact on the component making the noise. If Hickam is a dealership, they should have conducted Goodwrench multipoint inspection. Find out from them what that inspection entails. Went to the dealership yesterday for truck maintenance and wanted to hear the 2016 SS while I was there, the battery was dead. So don't assume the battery is good based on the age of the truck.

 

If this was me I would disconnect the battery for 10 minutes or so and see if everything resets. If it was still making the sound, the battery would still be on the hook. I would take the battery in to check the volts, recharge if low, then see if it will hold the charge. An auto parts store could tell you volts, low, and if the battery can hold a charge. The issue should have the dealership stumped, but whatever it is needs juice from the battery or else it wouldn't be making that sound? Ask the service department what are they going to do and if you decide take the truck in, I would tell them to look at the battery first or else you run the risk of them disassembling parts.

 

Anything that goes wrong with my truck and I don't know exactly what it is, I usually start with the easiest to get to and the cheapest component in the link. In your case the battery would be a no-brainer for me.

[Jsdirt]

Take the battery out of the equation, and I bet the sound goes away. Whether it's low or fully charged probably isn't going to matter - something has failed or is failing ... or is just poorly manufactured, as was the case with my singing transformer.

 

In my case the transformer worked, but emitted a continuous tone almost identical to the sound this truck is making. Made in China ...

 

I had the dead battery issue with my '07 when it was new. No explanation was given as to why it totally died in less than 12 hours, on 3 separate occasions. I blame the electronics. With Onstar and everything, whose to say that some unethical individual couldn't trigger a battery drain remotely, in order to drum up dealership business? Anyway, the dealer tweaked the computer under warranty to output a bit more, and I didn't have an issue until years later. After towing my stuck ATV with plow out of the snow, the wife parked it in the garage. I went out the next day, and it was dead. None of the light switches were in the on position when I checked. Another mystery. Still ended up getting 8 years out of that battery, and sold on Craigslist for $40. Probably would've gone a couple years longer if not for the rogue electronics in this thing ...

 

 

A battery that new ('14) could easily be restored to like new condition with a 3-stage temperature-sensing charger, or any decent charger for that matter, if it was dead or just low.

[The Zip]

Take the battery out of the equation, ....... - something has failed or is failing ... or is just poorly manufactured, .....

 

To tell you the truth, if my truck wasn't making that sound before I took it to Hickam, I'll be thinking what the heck did they do. I agree with the above comment but I would keep the battery in the equation.