2014 5.3 engine chirp

jtdoswell · November 27, 2014

OK. I have a 2014 ltz z71 and I honestly have no complaints . I do have a question.... while the truck is running in V4 , when it switches back to V8 mode. It sounds like a bird chirping .. it does it every time. Its not really loud , but its noticeable. And I'm more curious than anything if that's normal ...

BigBadSierra · November 27, 2014

There is a flapper valve in the exhaust that closes when it goes into v4.

I suspect your hearing it. You may want to have it looked at.

2016 Sierra Owner · November 28, 2014

Ok this chirping noise everyone complains about. Do you hear it with the windows up or down? I've had my truck a little over a year and just turned 9500 miles. I've never heard anything when mine switches.

fondupot · November 29, 2014

bolt the flapper valve open behind the muffler near the rear axle. Problem solved.

jtdoswell · November 30, 2014

I hear the sound with windows up and with windows down and it now just comes and goes. Kinda hoping it goes away on its own

20Denali22 · December 2, 2014

I hear the sound with windows up and with windows down and it now just comes and goes. Kinda hoping it goes away on its own

It won't, clamp it open and save the headache

jtdoswell · December 2, 2014

Do any of you know what the purpose of the flapper is anyway ?

2016 Sierra Owner · December 3, 2014

The flap is there from what GM says to prevent the drone you get in V4 mode. Some folks that have clamped that valve open say there is a "helicopter" sound out of their trucks.