Does Anyone Know What This Valve is Called or What It Does?

[WillieFlo]

For the last few months, my wife's Denali has sounded like crap for about 10-15 seconds on cold start ups in the mornings. Well, I finally got it on jack stands, slipped underneath it, and was able to pinpoint the culprit of all the clattering and clanking going on. There's a valve between the cat and the muffler with a rotating spring controlled knob on it staying shut......The spring is kind of weak, allowing the valve to stick closed until it warms up. It causes a bunch of clattering and sounds like a bunch of plastic pellets bouncing around inside the exhaust or muffler. The valve also makes a metal clanking sound until it finally opens......Noise is gone now that I rotated it back and forth a few times, and hit it with some dry lube/graphite.

Does anyone know what this valve is for and what it's called?

 

[tirekicker]

hey..there really is a such thing as a muffler bearing ! just kidding ...everyone calls it a "flapper" and its to help with drone when switching to v4 and back

 

[Denali Brad]

Pretty sure that's the Fetzer valve...

 

[OR VietVet]

I think if you lube that "muffler bearing" the noise will go away. I thought, did not know at all, that it looks like it is for partial exhaust flow blockage to help heat up the cats and then when hot enough it opens fully. I do think I heard the word "flapper" valve on here before but unsure and know I have not heard of a "Fetzer Valve" anywhere.

 

[iamdub]

People usually lock it in the open position. IIRC, the most common method is called the "bolt mod". I've seen hose clamps and stainless tie wire used as well.

 

[WillieFlo]

Thanks all!

 

[gooffeyguy]

For the last few months, my wife's Denali has sounded like crap for about 10-15 seconds on cold start ups in the mornings. Well, I finally got it on jack stands, slipped underneath it, and was able to pinpoint the culprit of all the clattering and clanking going on. There's a valve between the cat and the muffler with a rotating spring controlled knob on it staying shut......The spring is kind of weak, allowing the valve to stick closed until it warms up. It causes a bunch of clattering and sounds like a bunch of plastic pellets bouncing around inside the exhaust or muffler. The valve also makes a metal clanking sound until it finally opens......Noise is gone now that I rotated it back and forth a few times, and hit it with some dry lube/graphite.

Does anyone know what this valve is for and what it's called?

View attachment 343409

Doesn't it have "DRONE VALVE" and a part# stamped on it?

 

[WillieFlo]

The Left side of it was unreadable due to the corrosion, staining, etc..........all I could see was "VALVE".

 

[STORMIN08]

i hose clamped that dude wide open long ago...helps keep it from rattling as it gets weak

 

[gooffeyguy]

Lets not forget that Cardi B song (WAP) that everyone plays and it even won awards at the American Music Awards LOL

Actually, I'd like to forget it, but still, funny how that crap doesn't get censored as much as much less ****** words