High pitch noise

[hitesh9]

Mine is a 2001 I30, 85K miles. When I start the defogger, there is a high pitch squealing noise which increases as I accelerate. This comes only when I have the "Automatic" ON. When I select Manual for heating, I do not hear this noice. From other threads I have read here, I think this has something to do with the A/c compressor as it activates in the Automatic mode.

Appreciate some help in figuring what's wrong and what needs to be replaced.

[loystock]

In essence, the noise is only present when the compressor is engaged. If so, the problem could be on the compressor drive (clutch-pulley assembly) and/or the compressor itself. You can also check the belt tension and it's possible (though remote) that it's coming from the Idler pulley.

Once the problem is confirmed on the AC compressor-drive, the job is best left to certified HVAC technician. It is illegal to discharge refrigerant into the atmosphere.

If you have experience working with AC system, it's possible to pull out only the drive components (clutch disc and pulley) for inspection/replacement w/o breaking the AC line. But the access is tight and require special tools like clutch disc puller and pulley puller (can be rented from AutoZone).

[NutriaforBreakfast]

Might just be the belt driving the AC pump. See if the belt is wornfirst-or it might be a little loose

[hitesh9]

Thanks both for responses. I have seen the compressor belt and nudged it. Its not worn and feels tight enough. I suspect its the a/c compressor pulley/clutch. I have never worked on A/c, and replacing starter is the max I have ventured. I have seen the FSM and aside from requiring the special tools, I did not find any mention of refrigerant. If I attempt to remove compressor, will I be letting the refrigerant gas out ?

Another related issue I have ignored so far is a similar noise that comes when I cold start, stays for a while, increases with acceleration and then vanishes. This noise comes when I have not engaged the compressor and appears to be coming from the belts. Belt-dressing helped for a while, but not anymore. Any suggestion here ?

[loystock]

You cannot remove the compressor without breaking the AC line and thus discharge refrigerant into the air. Special equipment is required to capture and store the refrigerant. You also need to know the exact amount of R-134a and oil needed to service the AC. Also, once AC lines are exposed to atmosphere, water vapor will enter the system and degrade the cooling efficiency. A vacuum system is need to purge the AC line of water vapor and other contaminants.

Belt dressing is just a patch and won't last. You may need to replace the belt(s). If belt tension is good and yet you're getting some noise - check the alignment of the belt and pulleys. Your Idler Pulley (bearing inside) may also be failing.

OEM parts can be bought from NICO sponsor, IoS - everythinginfiniti.com or everythingnissan.com @ 25% off MSRP.

[hitesh9]

ok, so I'll not touch the compressor..never. Let me try the belts and idler pulleys over the weekend.

[hitesh9]

Sorry about the delay. I tightened the hex nut above idler pulley which certainly reduced the noise for a few days, but its back with a vengeance. So it does appear to be the idler pulley, and not the belt which is causing the noise.

I'll take it to Pepboys, for both a/c compressor and the idler pulley. Let you know how it goes. I sure hope I don't have to replace the entire compressor, but just the disc and pulley/ belts.

[loystock]

As for the Idler Pulley, most likely, it's just the bearing that needs to be replaced (requires a machine press). I'm not sure if Pep Boys will go that route. There is no need to replace the Adjuster Assembly (of the Idler Pulley), just the pulley if they can't replace the bearing.

[hitesh9]

Got it. Will try to get Pepboys to replace bearings if possible for Idler Pulley.I have not been happy with Inf of Lisle (stealer in the area) and Midas. Never used Pepboys for service before.

Now about the a/c compressor noise - its a big job and involves a lot of labour as you had put it ( refrigerant, vacuum et al ). I'm going to try my luck and replace the two belts - alternator/compressor/idler/shaft and PS pump/shaft.

With these 2 replaced - Idler bearing and belts - I'll return with feedback.

Thanks again, Loystock, for support.

[loystock]

My pleasure to help. And Happy Thanksgiving.

Actually, I've never taken my car to Pep Boys nor Midas. I do most of the work myself. If I can't/don't know how to do it, I have a trusted shop which can do a better job than dealership. However, for maintenance record and warranty purposes, I take my car to dealership at 15/30/60K and maybe 90K Service but I insist on Schedule 1 only since I have my own bi-annual maintenance schedule.