2008 Denali 6.2 Roaring sound while accelerating

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Bmurray256

TYF Newbie
Joined
Jan 5, 2022
Posts
7
Reaction score
4
So I have a 2008 Denali and when the HVAC power button is on it roars when accelerating until it hits high gear and goes away. This only happens when HVAC button is on, if it's off it accelerates with no noise at all. Need all the help I can get.
 

OR VietVet

Multnomah Falls
Supporting Member
Military
Joined
Oct 8, 2014
Posts
19,067
Reaction score
31,163
Location
Willamette Valley
Welcome to the forum.

Sounds like your noise is coming from the a/c compressor when it is engaged and accel from idle. Possible failing a/c compressor. The compressor does cycle with different modes, such as defrost. May be from radiator fans that are activated when HVAC is on. Does the sound get louder the faster you go? What is throwing me is the sound stops after hitting high gear, is what you said. Can you duplicate at all when sitting still and have the hood up and accel and listen or you do have to be moving and trans shifting? Need to check drive belt/idler/tensioner too. Others will chime in with other recommendations. Can you do a video of the noise?
 

Joseph Garcia

Supporting Member
Joined
Aug 2, 2018
Posts
6,386
Reaction score
8,311
Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.
 

intheburbs

Full Access Member
Joined
Aug 10, 2017
Posts
774
Reaction score
1,336
Location
SE MI
It's the cooling fan(s). At high speed they cycle down because you already have enough air moving through the radiators. Accept it, and let the truck do its thing.

ETA: I would check the fins of all the radiators looking for obstructions - leaves, bugs, etc. Also check your fluid. If it's not cooling effieciently, that could also cause excessive fan noise. The only time my 6.0 roars is 1) In the summer, 2) Very hot outside, 3) Usually towing, 4) Running A/C, and 5) Idling/slow speeds for a while.
 
Last edited:
OP
OP
B

Bmurray256

TYF Newbie
Joined
Jan 5, 2022
Posts
7
Reaction score
4
Welcome to the forum.

Sounds like your noise is coming from the a/c compressor when it is engaged and accel from idle. Possible failing a/c compressor. The compressor does cycle with different modes, such as defrost. May be from radiator fans that are activated when HVAC is on. Does the sound get louder the faster you go? What is throwing me is the sound stops after hitting high gear, is what you said. Can you duplicate at all when sitting still and have the hood up and accel and listen or you do have to be moving and trans shifting? Need to check drive belt/idler/tensioner too. Others will chime in with other recommendations. Can you do a video of the noise?
It only does it when driving. It’s the 2nd new compressor on the truck due to this. I’m confuse. I’ll see if I can get a video to upload.
 
OP
OP
B

Bmurray256

TYF Newbie
Joined
Jan 5, 2022
Posts
7
Reaction score
4
It's the cooling fan(s). At high speed they cycle down because you already have enough air moving through the radiators. Accept it, and let the truck do its thing.

ETA: I would check the fins of all the radiators looking for obstructions - leaves, bugs, etc. Also check your fluid. If it's not cooling effieciently, that could also cause excessive fan noise. The only time my 6.0 roars is 1) In the summer, 2) Very hot outside, 3) Usually towing, 4) Running A/C, and 5) Idling/slow speeds for a while.
Cooling fans??? Well shouldn’t they make this noise when I don’t have the hvac system on?
 
OP
OP
B

Bmurray256

TYF Newbie
Joined
Jan 5, 2022
Posts
7
Reaction score
4
It's the cooling fan(s). At high speed they cycle down because you already have enough air moving through the radiators. Accept it, and let the truck do its thing.

ETA: I would check the fins of all the radiators looking for obstructions - leaves, bugs, etc. Also check your fluid. If it's not cooling effieciently, that could also cause excessive fan noise. The only time my 6.0 roars is 1) In the summer, 2) Very hot outside, 3) Usually towing, 4) Running A/C, and 5) Idling/slow speeds for a while.
All fluids are full, engine runs at operating temperature as it should.
 

Forum statistics

Threads
128,781
Posts
1,805,314
Members
91,760
Latest member
MyCleftNut

Latest posts

Top