I have the same exact problem. I am currently riding with no AC, I took the belt off t prevent further damage. It's the compressor locking up and causing extreme stress on the tensioner causing it to violent shake and it sounds like a mini jackhammer upon acceleration. You need a new compressor. If you keep driving it like that, it can destroy the belt and/or tensioner and the flailing belt can damage the transmission cooler lines which run right underneath it. Look up this GM Tech service bulliten for more info. TSB 03-01-38-019A
Here is the info on the TSB:
Underhood Rattle Noise Heard on Acceleration (Check A/C System Performance and Compressor Operation) #03-01-38-019A - (Sep 3, 2004)
Underhood Rattle Noise Heard On Acceleration (Check A/C System Performance and Compressor Operation)
2003-2004 Cadillac CTS
2002-2004 Cadillac Escalade, Escalade EXT
2003-2004 Cadillac Escalade ESV
2002-2004 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe
2002-2004 GMC Denali, Denali XL, Savana, Sierra, Yukon, Yukon XL
2002-2004 Commercial Upfitter Chassis Vehicles
2003-2004 HUMMER H2 with Air Conditioning (A/C)
This bulletin is being revised to update the service procedure and parts information. Please discard Corporate Bulletin Number 03-01-38-019 (Section 01 -- HVAC).
Condition
Some customers may comment about an underhood rattle noise heard on acceleration or a sudden loss of A/C system performance.
Cause
Service Information
This condition may be caused by liquid slugging of the A/C compressor. This condition may cause an internal failure in the A/C compressor. The serpentine belt tensioner and serpentine belt may also be damaged.
Correction
Technicians are to check the A/C system performance and compressor operation using the following repair procedure:
1. Open the hood and inspect the A/C compressor for damage and to see if the compressor is seized.
Verify that the serpentine belt is not damaged or missing. If the A/C compressor is seized, proceed to step 5.
2. Perform the A/C System Performance test. Refer to the Heating, Ventilation and Air Conditioning (HVAC) section of SI. Correct any performance concerns or refrigerant leaks that are found.
3. Inspect the vehicle for other possible sources of A/C compressor noise or performance concerns. Refer to Corporate Bulletin Number 01-01-38-013 for more information.
4. After all other possible sources of A/C compressor noise or performance concerns have been eliminated, only then should the A/C compressor be replaced.
5. Remove the A/C compressor. Refer to the A/C Compressor Replacement procedure in the HVAC section of SI.
6. Inspect the transmission cooler lines for damage due to contact from the serpentine belt. Replace the transmission cooler lines if necessary.
7. Install an inline A/C system filter. Refer to Corporate Bulletin Number 01-01-38-006C for more information about A/C system flushing and filter installation procedures. An A/C system flush is not to be done unless prior authorization is given by the GM Area Service Manager (in Canada, the District Service Manager).
8. Install an A/C Suction Screen. Refer to Corporate Bulletin Number 01-01-39-003A for more information about A/C suction screen repair recommendations and procedures.
9. Install a new A/C compressor. Refer to the Compressor Replacement procedure in the HVAC section of SI.
10. Install a new orifice tube for the front A/C system. Refer to the Expansion (Orifice) Tube Replacement procedure in SI.
11. If the vehicle is a 2003 model year Chevrolet Express or GMC Savana van, the vehicle may require a new accumulator. Refer to Corporate Bulletin Number 03-01-38-016 for more information. This bulletin refers to an updated design accumulator that may improve the performance of the A/C system.
12. Install a new serpentine belt tensioner and serpentine belt if they have been damaged due to A/C system slugging or an A/C compressor seizure. The serpentine belt tensioner may have broken stop tabs and/or a missing front cap.
13. Verify proper operation of the A/C system.
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