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Discussion Starter · #1 ·
Does anyone else get creaky groaning sounds switching between certain HVAC modes? Whatever duct piece that rotates for the different circulation modes needs some grease or something.

My initial assumption is that it's too time consuming and risky to get to it and it's just the first of N noises that the car will accumulate with age? 2016 42K miles, driven hard but well taken care of.

If someone has service manual steps to open up the bottom of the dash to get to some of the HVAC ducting that would be super appreciated!

I tried recording the sounds on my phone in the below video but they're hard to hear unless you have the volume cranked. It definitely sounds worse and louder in person.

 

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May be the classic GM blend door problem that's plagued their HVAC system for many years. Pretty big job to fix on the SS if that's the culprit.
Best of luck!
 

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Discussion Starter · #4 · (Edited)
An unfortunate follow-up... I replaced the cabin air filter the other month only to discover the previous filter installed by Firestone wasn't seated correctly and was letting some dirty air into the system for 2 years... Dawned on me this morning that it likely caused the noise to develop as one of the HVAC hinges likely got a small amount of air impurities built up in it...

Hopefully not an issue any other SS owners have to deal with. Needless to say my tire warranty and lifetime rotation at Firestone is null and void, they can keep the change...
 

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Wow that is interesting for sure. Not my SS but wife's Suburban we have had the coolant noises in past, it was a trapped air bubble in the system. Had to lift front end high as I could while running with cap off to "burp" the system.
 

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Discussion Starter · #6 ·
Wow that is interesting for sure. Not my SS but wife's Suburban we have had the coolant noises in past, it was a trapped air bubble in the system. Had to lift front end high as I could while running with cap off to "burp" the system.
Glad you could get rid of that noise!

Assuming my speculation is correct I'll probably never be able to get to the HVAC blend door hinge to clean/lubricate it unless it breaks requiring replacement and since I don't prefer that to happen I'll just have to live with the occasional creak/squeak whenever it happens...
 

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Inception Date: 1 March 2017, Chevy SS Sedan, White, A6, Spare, No Sun
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I never heard it called a 'blend door hinge.' But I'm all-too-familiar with the HAVC 'hot water control valve.' So maybe they're different parts. 🤷‍♂️ AnyWho, mine has started making that sucking snort. The noise reminds me of an old-fashioned bellows used to stoke a fireplace.
👴
 
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Blend door needs some lubrication from OP video...hear it with engine idling even.... could also be the actuator doing that squeak but their issue is usually they lose their position and you get clashing of the doors. (and hopefully a code!) There are usually 3 actuators in these auto dual / bi mode systems. I dont discount foreign debris, could even be corrosion on a metal part. Do you use AUTO most of the time and let the system decide flow and temp....or do you have it set more manually.????
 
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Just watched the video. Noise seems to be from the "mode" door rather than the blend door I mentioned earlier.
 

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Discussion Starter · #10 ·
🤷‍♂️ AnyWho, mine has started making that sucking snort. The noise reminds me of an old-fashioned bellows used to stoke a fireplace.
👴
That's somewhat relief for me knowing Firestone's poor worksmanship isn't necessarily to blame... We're somewhat in this together then at least :confused:

Blend door needs some lubrication from OP video...hear it with engine idling even.... could also be the actuator doing that squeak but their issue is usually they lose their position and you get clashing of the doors. (and hopefully a code!) There are usually 3 actuators in these auto dual / bi mode systems. I dont discount foreign debris, could even be corrosion on a metal part. Do you use AUTO most of the time and let the system decide flow and temp....or do you have it set more manually.????
I leave it on Auto and only change the temperature. If I start smelling exhaust on the highway or behind a smelly truck I'll switch to recirculation. Should I instead manually set them? How hard is it to get to the parts to lubricate them?

Just watched the video. Noise seems to be from the "mode" door rather than the blend door I mentioned earlier.
Gotcha! I'm assuming it's not easy to get inside behind the dash in order to lubricate these parts...
 
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