2016 Denali XL - GMC Refused to buyback!

[ajs800]

when testing, put it in M5 to avoid the V4 mode and see what the results are. If there's buffeting and/or vibrations, you know it's not V4 related. I would like to think a dealer would know better, but I've learned they don't have a clue sometimes regardless of all good intentions. I'm certain the vibrations will be less without V4, but guessing the buffeting will still be present.

 

[tenbigblinds]

My advisor just called. He definitely felt the pressure (frequency) and they engaged the GM engineering team. The team asked them to leave some form of valve open and try it. He said the pressure was gone when they tested it. GM engineers told them to replace the exhaust system.


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[ajs800]

A valve within the exhaust system?

 

[tenbigblinds]

A valve within the exhaust system?

Yes. I believe that's what he said.


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[Tahoe14]

Isn't it a flapper of some sort for the V4 mode.

 

[tenbigblinds]

Isn't it a flapper of some sort for the V4 mode.

He said it was a "pressure valve" or something


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[ajs800]

Curious if this cures buffeting/pressure feeling. Most with buffeting experience in v4 as well as other times.

Hopefully in your case it is only when in V4 mode.

 

[tenbigblinds]

It's what the GM Engineers advised. They are leaving the valve open, new exhaust system arrives on Tuesday.

My concern is I took it in for the 3rd time for "low speed vibration". They wouldn't acknowledge that but did say when they test drove they noticed droning/pressure.

I will update again when I get it back with the open valve and again after they replace
Exhaust.


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[mck024]

Where exactly is this valve located?

 

[tenbigblinds]

Where exactly is this valve located?

I am picking up the car today. I will post soon after.


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