ASI Resolution - High-Pitched Tone Heard Inside Vehicle When A/C Compressor is Engaged (Replace Compressor Discharge Hose Assembly)
| Subject: | High-Pitched Tone Heard Inside Vehicle When A/C Compressor Is Engaged (Replace Compressor Discharge Hose Assembly) |
| Models: | 2003-2006 Cadillac Escalade EXT |
| 2003-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe |
| 2003-2006 GMC Sierra, Yukon, Yukon XL |
| 1500 Series Vehicles Only with 4.8L, 5.3L or 6.0L Engine (RPOs LM7, LQ4, LQ9, LR4 and L59) and Front Only Air Conditioning (RPOs CJ2 and CJ3) and a Short Condenser |
| 2005-2006 Cadillac Escalade, Escalade ESV |
| 2005-2006 Chevrolet Suburban, Tahoe |
| 2005-2006 GMC Yukon, Yukon XL |
| 1500 Series Vehicles Only, Built in February 2005 or Later, with 4.8L, 5.3L or 6.0L Engine (RPOs LM7, LQ4, LQ9, LR4 and L59) and Front and Rear Air Conditioning (RPOs CJ2, CJ3 and C69) and a Short Condenser |
| Attention: | Parts are released for 1500 series vehicles with front only air conditioning and certain utilities with front and rear air conditioning. The length of the condenser on the utilities must be measured before ordering a new part. Only utilities with a short condenser have a new part released for them. Utility vehicles that are within the model year ranges above but have a long condenser are not covered by this bulletin. |
This bulletin is being revised to provide the correction information for Advanced Service Information Bulletin Number 04-01-38-014. Please discard Corporate Bulletin Number 04-01-38-014 (Section 01 -- HVAC).
Condition
Some customers may comment on a high-pitched tone that is heard inside the vehicle when the Air Conditioning (A/C) compressor is engaged.
Cause
This condition may be caused by refrigerant pulsations within the A/C system. The noise occurs between 800 and 1000 RPM and is often called an "Off-Idle" noise. This noise is detectable only when the A/C is on.
Correction
Do This | Don't Do This |
|---|---|
Install a new A/C compressor discharge hose assembly. | Do not replace the A/C compressor. |
Technicians are to verify that the customer concern is heard when the A/C is on and that it goes away when the A/C is turned off. Verify that the noise is heard at low engine RPMs only, typically between 800 and 1000 RPM. The noise is not measurable above 1200 RPM or below 700 RPM. If the customer concern is present, then technicians are to perform the normal diagnostic procedures for an A/C system concern. The ACR2000 should be used to check the A/C system performance, charge level and discharge temperatures. This will eliminate the possibility that another condition is contributing to this customer concern. If the A/C system is performing properly and all other possible sources of the noise are eliminated, then replace the A/C compressor discharge hose assembly. Use the proper part number hose as described in the parts information box below. Use a new hex head bolt, P/N 11515757, to attach the new hose to the A/C compressor discharge port. Verify that the noise has been eliminated and that the A/C system operates normally.
Parts Information
Important: Some of the utility vehicles listed in this bulletin were built with two different length condensers. All the pickups and utilities with front only air conditioning will have short condenser, but the utilities with rear air conditioning were built with both short and long condensers. This changeover occurred in February 2005. The short condenser is 762 mm (30.0 in) long. The long condenser is 914 mm (36.0 in) long. Be sure to measure the length of the condenser before ordering any parts when working on a utility with rear A/C.
Part Number | Description | Qty |
|---|---|---|
11515757 | Bolt-Metric Heavy Hex Flange Head | 1 |
15816513 | Hose ASM-A/C CNDSR (Cadillac utility vehicles only, built February 2005 or later, with a short condenser) | 1 |
15825113 | Hose ASM-A/C CNDSR (All 2003 to 2006 front A/C only vehicles) (Chevrolet and GMC utilities with rear A/C, built February 2005 or later, with a short condenser) | 1 |
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
D3082 | Hoses And/Or Lines, Refrigerant-Compressor Discharge - Replace | Use published labor operation time |
Add | To Recover and Recharge A/C System | Use published labor operation time |
