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.

[Rush78]

Ran into a mechanic there today who told me two things I can try the next time I hear the noise. 1) take off the gas tank fill cover, if it stops there could be a problem with the evap system. 2) take off the oil cover, if this stops it then it's the PVC valve.

Still going to swing into Hickman motors on my why home from work in the morning. Going to bring up the PVC to them and ask to speak to the mechanic who said he has the same problem.

[Rush78]

The idea of the PVC not working correctly is that there could be unburned fumes venting from the crank case. This could also cause the oil to go dirty or sluggish, from what i read somewhere.

[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.

[GLSierra13]

Could it be coming from the A/C compressor or an A/C line somehow? I know next to nothing about A/C but the compressor is in that same area. Is it somehow bleeding off excess pressure?????

[Rush78]

Ok. So here is a undate on the Squealing noise. I finally got to hear it again and this time i disconnect the battery cable. The result was no different, even with no power from the battery you can still hear the noise. I did so more poking around and it sounded to me like it was coming from the alternator area, at one point to me it actually sounded like the alternator.

Now Like i mentioned before i don't know much on the whole evap system but could it be a purge value sylenoid making that noise? I am not sure where it is too on this truck. But could that be what the Hickman mechanic was talking about.

I have another video but having trouble uploading it.

[The Zip]

Point taken about the dealership. I shop at Rockauto, for six bucks you can get the entire valve. I would try this if this was happening to me, but what you don't want to do is spend a lot of money on an issue you haven't yet figured out. What happened with the dealer fix? As I think about it, this is a new truck. Only thing you will lose is being inconvenienced by taking it to the dealership, unless your bumper to bumper has expired.

 

https://www.rockauto.com/catalog/raframecatalog.php?ck[iD]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[php_SESSION_ID]=pnqo4nf718hstedgept3cll8t1

[Rush78]

Lol...the old time mechanic was a Captain of mine at work. He doesn't work with GM. He said that there is a valve or something there that he believes they use to check the fuel pressure and possibly they never tighten it or something when they did the inspection. Now this was years ago, he's not up on the new models with the in closed system. I asked Hickmans what they do to check the fuel pressure and stuff lime that when during an annual inspection and they said all they do is hook it up to the computer. If there was a problem it would show up there or on your dash. Nothing showed up and nothing on the dash. Truck runs perfect lots of power and get up.

I have thought about and going to doing what you said and pulling the negative when i hear the noise again. Like you said that takes the electrical out of the question all together then if it still continues. Now i just have to wait for it to happen again, who knows when that will be.

[Rush78]

Here is the new video.

Watch "2014 Silverado Squealing noise!" on YouTube

 

[Rush78]

Hopefully this video does make it to GM and they actually do come out with an official statement on the problem, weather it is a recall or what. I am interested to see what the head office is actually going to say. Until then my truck is covered under warranty for 160 000 i got a lot of going for something to happen, i am lucky if i put 15 000 on her a year.

If and when it do happen again i ll take another video pulling off the negative cable that way i can post it and got something else to go back with if it does stop.

[Jsdirt]

Just FYI - the EVAP system has no bearing on how well the truck does, or does not run. It's a "feel good" system designed to keep treehuggers happy - nothing more. Somehow gas fumes are to blame for all the world's ills. It could just be the fact that they screw all of us by diluting the fuel with ethanol, and so you need a sealed system in order for the fuel to not go stale in 3 days ...

 

EVAP started in '96 with OBD-II emissions systems. It was there before that in the form of charcoal canisters, but you could easily disconnect those and throw 'em in the trash without failing inspection due to a "check engine" light. Now if there's a tiny little leak, it throws the light ... and in communist states like mine, you fail inspection, and if your not mechanically inclined your forced to shell out HUNDREDS of dollars in repairs.