Ac Bearing Whine

[Eddie 70]

If you had a whining noise in the rear differential due to improperly set gear backlash, it would come in around 45-55 MPH (regardless of which gear the truck is in) and in some cases the noise would be there only during coasting (no gas) or there would be steady whine while under load. I have seen both cases on other trucks (Nissan).

 

There is a possibility that you may have transmission pump whine or power steering pump whine, or even alternator bearing, or tensioner whine. To eliminate the last three, remove the serpentine belt and run the truck at idle for a short time and accelerate past 1,500 RPM. If you do not hear the whine with the belt off, the source is probably the power steering pump, alternator, or one of the idler pulleys. Run the engine with the belt off for only several seconds as there will not be alternator charging or power steering assist, and water pump will not operate.

 

You can also have the A/C compressor bearing whine, and you can eliminate that by removing the A/C compressor belt and running the engine. If the noise is still there, it is not the compressor bearing.

 

I used this systematic approach with my truck when I had power steering pump whine and I narrowed it down to that after trying another alternator and tensioner.

 

GM has problems with their power steering pumps whining. I have heard many GM SUVs drive by at slow speed whining like crazy. Shame on GM for not fixing this issue.

 

I agree that whining noise like this can be very frustrating, especially if they claim that they cannot even duplicate it.

 

 

Mine has a whine that has made me do a lot of troubleshooting. I found after removing the both belts that my whine went away. Reading the post quoted here, it seems that the bearing in the AC compressor in mine is making the noise. Now, what does it take to get this fixed?