A/C Noise

[ozmanyyy]

Hi guys,

I have an 02 LC with Nav with about 115K miles.

I need help diagnosing or at least getting a little knowledge about a noise.

I'll just summarize what I know. It started a week or so ago. There's noise coming from the engine bay and It goes up and down with the rpm's. Its a noticeable "whine" is my best description and its not happening all the time. It is not the heat shield noise, as I already had that prior to this.

I narrowed it down to the A/C. In other words, if its making the noise, it immediately stops when I hit the A/C button. So Climate control (Auto) can be on and no noise unless the A/C button is on.

Ok, so I take it to my dealer and explained all this. An hour later, he calls me back and tells me a host of recommended "services" ( Parking brake sticky, Spark Plugs, power steering flush ) for quite a lot of money and then finally he tells me they think the noise is the heat shield. $250 to fix. I reiterate again that its not the heat shield as I already knew about that. He says he'll check with the mechanic again. Calls me back 15 minutes later and says they hear a slight sound from the A/C compressor and say its about $1400 to replace ( with some lines and a switch ). I'm a little skeptical because its quite noticeable so it may be the compressor but I don't have any faith whether he's hearing the same noise.

I decline and have to eat the $132 diagnostic. He won't let me apply that to anything but the heat shield work because everything else would be considered maintenance. That will be my last time at that dealer. I don't mind paying the money if they had a clue. But they spent an hour checking the car for everything unrelated and 10 minutes to tell me they think its the compressor. Fine, rant over, incompetent dealer, I won't go back to them again.

But back to the noise. Is the A/C compressor the only possible culprit ? The A/C does work really well, btw, except for the noise. I also have to investigate whether its really a $1400 fix.

I did a lot of searching and I couldn't find much with my symptoms. Probably because there's a lot of "noise" threads. The only possible one was a thread with a (99) TSB for A/C expansion valve.

Any other thoughts ?

Thanks in advance.

 

[TXLX100]

Sounds like AC compressor whining to me. Could be the AC compressor or a pulley/tensioner going bad and the extra load from the compressor running causing the noise. When was the last time the drive belt was replaced? Does the noise go away when the compressor shuts off?

 

[ozmanyyy]

At the moment, I can only say for sure that the noise will go away when I turn the A/C off. If the A/C is on, it's fairly consistent but it does come and go. So it could be that it's going away when the Compressor is kicking off.

I had the timing belt service done recently ( months ), I think that was done as well, I'll have to check.

Is there a way I can visually inspect whether it's only a pulley/tensioner or belt ? I'm not even sure which side the compressor's on, but I'll pop the hood when I'm back home.

Thanks

 

[TXLX100]

You can follow the silver AC lines to the compressor. I think it's about mid height on the engine, I can't recall. You can't normally visually inspect pulleys (you can if they've seized up!), you'll need a mechanic's stethoscope and place the tip on the main pulley bolt and listen for rough sounds.

Just some things to check and potentially rule out since the compressor and repair aren't inexpensive.

 

[ozmanyyy]

I found where it is but I can't really tell why its making the noise. I'll have to try to have it looked at by someone else at some point. Luckily, I won't really be pressed for A/C in CT anytime soon

I did a quick search though, and a new Denso compressor with Clutch is under $450. The dealer roughly estimated about $1000 parts and about $400 labor. Oh well, buyer beware I suppose.

Thanks

 

[ozmanyyy]

Hi guys,

So now that its summer, I was going to finally get this addressed. When I turn the AC on, I noticed the noise wasn't happening, but I was also getting hot air. I looked under the hood and saw that the compressor didn't seem to be engaging any more. The part with the holes near the oil filter wasn't spinning. This should happen as soon as I turn A/C on, correct ( its plenty hot and I have the temp at max cold ) ?

I guess this pretty much spells time for a new compressor, right ?

Thanks
Oz

 

[n55luvr]

If you lost all the refrigerator the compressor won't cycle at all. I asked similar question recently. Once I plugged a hole in the line, refilled it was fine and cycled on and off.

When in auto the compressor won't run all the time unless on max cool. you can feel it kicking on and off along with seeing a small rpm jump when sitting still.

 

[ozmanyyy]

If you lost all the refrigerator the compressor won't cycle at all. I asked similar question recently. Once I plugged a hole in the line, refilled it was fine and cycled on and off.

When in auto the compressor won't run all the time unless on max cool. you can feel it kicking on and off along with seeing a small rpm jump when sitting still.

Ok, so then the refrigerant must be gone.

So do you think that low refrigerant would have caused the whining/wheezing noise from the compressor in the first place ?

Also, if I have refrigerant added and the noise comes back, would I need to have it added again if I had to replace the compressor (meaning I have to pay for the service twice)?

 

[n55luvr]

From what I gathered the refrigerant is also a lubricant but I think if your compressor cycled on (making the noise) the system had enough refrigerant so I doubt low would have caused the whining noise. I think things are pointing to faulty compressor (plus possible line leak).

With all that being said, I think knowing if a faulty compressor can allow a leak is critical piece of info. Hopefully others will chime in.

 

[spressomon]

The whine is, more than likely, a failing bearing within the compressor. A similar whine will present itself when any of the bearings apart of the alternator, pulleys, etc., wear out (age and/or lack of grease within the cartridge style bearing).

The A/C system is a sealed system. Refrigerant doesn't 'wear out' or need topping off unless there is a leak within the system. If the compressor clutch is not activating it could be the refrigerant pressure is below the 15psi (?) threshold (designed to protect the compressor when refrigerant leaks from the system), the clutch itself or possibly the fuse. Any A/C shop/tech will be able to quickly determine the cause.

The A/C compressor, if it needs replacement, is not difficult to swap but the DS CV shaft usually needs to be pulled to get access at 2 of the 3 bolts that hold the compressor to the lower block; hence the labor $$.

Typically compressor oil is added to a new system (installed into a new condenser and/or compressor) separately. Some refrigerants contain the oil...especially those sourced from the retail parts suppliers. Ditto for the optional leak detection dye.

To find a leak the system will usually need to be charged with refrigerant containing a leak detection UV dye (assuming the dye has not already been added to the system). Then, using a UV type flashlight and yellow glasses (source these from any auto parts store for about $20) go over all A/C lines and fittings until you find the leak.

Then once you replace the leaking line(s)/A/C component(s) you will need to vacuum the system before re-charging with refrigerant (and oil as needed). It sounds like, presuming the whine is coming from the A/C compressor, you should replace the compressor apart of this repair.

I'm going through my own "Private Idaho"/indoctrination for all things 100-Series A/C right now...

 

[ozmanyyy]

Thanks for the response guys. I'm going to have my local mechanic check it out tomorrow for a diagnosis. I'll post back what they find.

Oz