Jump to content

Annoying Squeak every time cylinders reactivate from V4 to V8

Z71Texan

By Z71Texan
in Ask A GM Technician

 Share

Recommended Posts

Z71Texan New Member

Z71Texan

Posted
Posted

At 1800 miles I noticed that my truck started or has been making this really annoying, high pitched squeak every time it switches from V4 to V8 on the highway. It almost sounds like a valve opens up when the cylinders reactivate and is driving me nuts!! I don't hear anything when it goes from V8 to V4. Unfortunately, I don't get to enjoy the "quiet cabin" GM advertised because of the squeaking.

 

Has anyone else experienced this issue? I have the 5.3L V8 in a 2015 LT Crew Cab short box Z71

Fishingbear Enthusiast

Fishingbear

Posted
Posted

I have this same problem on my 2015 1500 Sierra Crew Cab SLT 5.3L short box. It sounds like two pieces of metal hitting each other every time I hit the gas when it it in V4 mode and shifts to V8 mode. I plan on taking it in soon to have it looked at. I've read on this forum that it has something to do with the exhaust system and a flapper valve. I'll post an update after I take it in a few weeks from now.

gmtech117 Enthusiast

gmtech117

Posted
Posted

It's the valve that opens up in the exhaust. Mine did the same thing, I put a bolt in it to keep it open at all times. The valve is only to cut down on drone when in v4 mode, not much of a difference when always open. If you take it to the dealer the fix is to replace the exhaust system, if you search it looks like a lot of people have had it replaced, only for it to start squeaking again later on.

  • Like 1
  • 1 month later...
Fishingbear Enthusiast

Fishingbear

Posted
Posted

I just got my truck back from the dealer and was first told that they "could not duplicate the problem". This was after they put 25+ miles on the truck. I then took the service manager for a ride and we both heard it right away. He then proceeded to tell me that it's "a normal operating characteristic of the vehicle" and that there is no fix. He also mentioned that there is a fix for the 2014's with the exact same problem but that GM has not issued a fix for the 2015's. He suggested I turn up the radio so I wouldn't hear it.

SILVER SLED Senior Enthusiast

SILVER SLED

Posted
Posted

Have him show you the bulletin where it's normal. There is a bulletin for the 14's, just because it hasn't inclueded the 15's yet doesn't mean they can't replace the exhaust/fix the 15's.

Z71Texan New Member

Z71Texan

Posted
  • Author
Posted

I just got my truck back from the dealer and was first told that they "could not duplicate the problem". This was after they put 25+ miles on the truck. I then took the service manager for a ride and we both heard it right away. He then proceeded to tell me that it's "a normal operating characteristic of the vehicle" and that there is no fix. He also mentioned that there is a fix for the 2014's with the exact same problem but that GM has not issued a fix for the 2015's. He suggested I turn up the radio so I wouldn't hear it.

Im sorry to hear that. I took mine to the dealer last month and the tech drove and I rode with him and he heard the squeak and within 5 miles he was sure it was reproducible and we could hear it from the back right side of the truck from the same butterfly valve in the exhaust. The tech read several bulletins for a couple hours and ended up ordering a new exhaust for the truck. It came in over the holidays and was installed the first week of this month and so far so good. No more squeaks =)

Fishingbear Enthusiast

Fishingbear

Posted
Posted

Im sorry to hear that. I took mine to the dealer last month and the tech drove and I rode with him and he heard the squeak and within 5 miles he was sure it was reproducible and we could hear it from the back right side of the truck from the same butterfly valve in the exhaust. The tech read several bulletins for a couple hours and ended up ordering a new exhaust for the truck. It came in over the holidays and was installed the first week of this month and so far so good. No more squeaks =)

 

So it sounds like your dealer replaced your exhaust because of the chirp and mine told me it was normal... and we both have 2015's. This is frustrating! I guess I better take it to another dealer for a second opinion. Please let me know if the noise comes back. Mine is so obvious and loud that I hear it EVERY time my engine goes from V4 to V8.

  • 2 weeks later...
ChadOD New Member

ChadOD

Posted
Posted

I also have a 2015 Silverado Lt1 5.3 sounds like a cricket chirping or sometimes it keeps going for like 10 seconds. I've seen posts here both claiming the 4wd switching in auto and the exhaust flapper valve. Z71 Texan you're saying the new exhaust solved the issue?

  • 1 month later...
Sierra Matt Enthusiast

Sierra Matt

Posted
Posted

I am also having this problem. The dealer says that some do it and some don't, and that its operating as designed and since GM has not come out with anything on it there is nothing he can do. First new truck in 15 years, but I'm getting tired of the same response to everything.

  • Like 1
  • 1 year later...
holty Enthusiast

holty

Posted
Posted

I just traded my '14 5.3L in and it had the chirp EVERY SINGLE TIME it went from V4 to V8 mode. Drove me bat shit crazy!

 

My new 2016 Denali does not (yet) make the noise.

  • 6 months later...
Tneely New Member

Tneely

Posted
Posted

My truck 2016 gmc sierra is squeaking something fierce. Bought it brand new... From what I've been told it's a flap valve in the exhaust system. Dealer or G.M. still haven't fixed the problem. Nothing but the run around and lip service!

My truck 2016 gmc sierra is squeaking something fierce. Bought it brand new... From what I've been told it's a flap valve in the exhaust system. Dealer or G.M. still haven't fixed the problem. Nothing but the run around and lip service!

  • 3 weeks later...
GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted

Good afternoon Tneely,

 

We understand how this noise can be frustrating and assure you this is not the kind of experience we want you to have in your new truck. Please feel free to send us a private message if you'd like to discuss further, we’d be more than happy to assist. Hope to hear from you soon!

 

Best,

 

Bret B.

GM Customer Care

  • 2 weeks later...
sk Senior Enthusiast

sk

Posted
Posted

This is a known issue and is DEFINITELY the PEV (Passive Exhaust Valve). I don't have the PI number available but tell your dealer to check the TechLink bulletin from June 2014. Here is a cut-and-paste from the pertinent part of the TechLink (there are actual pictures in the online article):

The second noise condition is a whistle noise heard coming from the muffler area of the exhaust system. To diagnose this condition, temporarily lock the Passive Exhaust Valve (PEV) in the open position.
Equipped on all light-duty trucks, the Passive Exhaust Valve, located behind the muffler, acts as a broadband tuner in both V4 (Active Fuel Management) and V8 mode for a more refined sound.
Rotate the Passive Exhaust Valve counterclockwise. For testing purposes only, install a 1/4" x 20 x 2” steel bolt, nut, lock washer and two large standard 1/4" x 1” outside diameter washers (body washer) in the Passive Exhaust Valve.
If the condition is reduced or changes greatly in severity with the bolt installed, replace the exhaust system.
The vibration condition may be noticed in the seat or steering wheel when the truck engages V4 mode (Active Fuel Management). After verifying the condition, check the exhaust system for Ground Outs at the mounts and repair as necessary. For testing purposes only, install the bolt, washers and nut as described above. If the condition is reduced or changes greatly in severity, replace the exhaust system.

 

 

My dealer and I have been monitoring mine for a few months. As said above right now the only fix is to install new exhaust from the muffler back and the same style valve is still installed so many begin to squeak again in a few months.

 

 

 

  • 3 years later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled I?    Stribeck says that we need a certain amount of viscosity under conditions of load and velocity to prevent two surfaces of a know roughness from tearing each other asunder. And we have marketing trying to tell the masses that those two surfaced require less of that commodity due to more exact limits being placed on the same old clearances. We also know that there are limits to how hard something can before it becomes to brittle to be viable and to smooth to 'wet' the surface and that both of those conditions have been known and met since about the Second World War.    That viscosity value shook out at 10 centistokes at 212 F just under a hundred years ago.  Give this a look: [Anton Parr]     What is advertised is the Kinematic viscosity (mm2/s) or that which has been density adjusted but the value we are after is the dynamic viscosity (mPa.s) or true viscosity. You can see that this number is dependent on density thus base stock and temperature. You can also see that an SAE 30 doesn't reach that value in this example. However an SAE 30 that is at the upper end of the SAE 30 range; 12.5 cSt (mm2/s), might. 12.5 * .83 = 10.375 (mm2/s). If you could find an SAE 30 at the upper end these days.   Then there is the complication of viscosity modifiers or VII or VM, whatever you wish to call them. Polymers added to very thin base oils, perhaps 3 to 6 cP oils, that will meet the SAE *W30 spec at 'tested' shear rates and 100 C/212F  target temperature. So a polymer fortified base that is a fraction of the 10 cP requirement Stribeck insist upon.   This could be all well and good if those polymers didn't have two very problematic 'features'. They shear or loose viscosity both 1.) permanently and 2.) temporality. And they do both omitted in the advertised data with the distinct  purpose of deceiving the consumer of the actual operating state of the fluid. I've shown the example of Warren Oils COSTCO 10.91 cSt 5W30 formuation several times where the 100 C HTHS value is 6.9 cP!! That's the temporary shear down and with and SSI or shear stability index of 9.4 cSt. Note the intentional deception in using mixed units?    After a short while that 9.4 cSt oil has a viscosity corrected dynamic value of 7.8 cP. But as the SSI is still within the range of an SAE *W30 whose lower value is 9.3 cSt.    This allows them to continue to call this SAE 16 weight oil a 30 weight, the cake, and still meet the API requirements for fuel efficiency IMPROVEMENT mandated by the EPA. The eating of the cake. By the time you've worn out your motor doing the responsible thing by adhering to the warranty requirements, (the stick), you get deprived of the carrot, wear control. So sad, to bad.   So what can be done? Do I need actually say? [Anton Parr]       Even this must be monitored if the oil is on the low side and the VII an organic or you opt for a 0W40 with an even lighter base oil and more / higher MW VII. (Note the lower density of the 40 weight versus the SAE 30 mono-weight?)    There is another workaround. Temperature. An SAE *W30 run at a bulk temperature of between 180 and 195 F.    Being the belt and suspenders sort I am I do both. Run it cook and run it heavy.    In Part II I'll work the AW package. 
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      So, do I go elbow-deep on this thing or list it for sale and play dumb? Seems to "runs good."   I'm about $1200 away from having: -a rebuilt injector ($300) -a new cat ($250) -a new cat back exhaust (OE style) ($300) -a new AC compressor ($200) -AC refrigerant charge ($150)   In theory, this should rectify the obvious detracting issues from its value and operability. Cold AC with a non-squeaking AC pulley both sounds and feels good. An exhaust that isn't cut/hacked in 17 different places and doesn't vibrate on a crossmember would make it sound and feel less janky. A working cat would help the stink, and will save the earth, but *if and only if* the fuel system is working properly, which would also address the intermittent "rich" CEL.   Heard a good one... CEL for "Rich condition" means you haven't spent enough money on the truck lately, and it's letting you know.   Rebuilding the injector would seem to be the most important part. Replacing the cat would be secondary. I don't think mine is plugged or overly restricted, but it might be a little restricted? I have no good way to tell other than seat of the pants feel. I hate the smell.   The current theory is I have a rich idle problem: A bad fuel pressure regulator, or a leaking injector(s) being the highest probabilities. I already replaced the FPR but that doesn't mean its replacement isn't also bad. It was a new part from Dorman, but the packaging looked like it had been sitting on a shelf for 20 years.   This is the (single) upstream O2 sensor shown at idle. I'm getting a lot of "rich" it seems. Sometimes it stays high like that and doesn't drop down. That makes me think it's processing injector leaks or a partially stuck open injector.     Other times it looks like this. Nice oscillations between rich and lean, which is what I think it should be. Under load and at speed, the oscillations are nice and tight and uniform looking, high and low.     Fuel trims suggest the PCM is compensating pretty hard at idle to pull fuel out. But it's not enough to trip a CEL. Something about slowing to a stop: brake vaccum booster, EGR, or the EVAP purge is delayed, or there's pooled fuel in the intake again that's draining into a cylinder is enough to set the CEL. Of course, in two days of driving, it hasn't set. I was hoping to actually look at the freeze-frame data when it sets. IAT is high because it's idling on an 83 degree day here.  
    • Another JR
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By Another JR · Posted

      Have considered installing a DC to DC charger in your camper to replace your isolator?  
    • newdude
      Gas fill door

      By newdude · Posted

      Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • newdude
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By newdude · Posted

      No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...