urbanriz

Hello,

Wondering if someone could help me out. In July when the hot weather started we first used our AC, originally the RX in March and never tried / used the AC then. Out of warranty after 30 days and in July when we first used it we noticed the car would make a noise, kind of hard to describe, not exactly clicking or grinding .. took it to the mechanic and he said it was a worn AC compressor. He swapped it out for the exact same part. However, I still hear the noise. Kind of lost, I realised that when the car is in gear (drive, neutral or reverse) and stopped or near stopped it would start up and go away when you speed up or put it in park.

Any thoughts? Do you think it could be something serious? I put in $800 for the compressor already and fear it might be something bigger. The AC before the change and after the change blows very cold air and pickup of the car and everything else is perfect. Just this, drive me crazy. The noise I should note is not extremely loud but could question it if sitting next to the driver.

Thoughts?

gundy

I had a similar problem with my previous vehicle but it was unrelated to the A/C system. I would hear rattling coming from underneath the car when stopped and idling but it would go away once I reached a decent residential driving speed or better. I took it to one mechanic who told me all kinds of things that were wrong and it would cost upwards of $1000 to fix. I took it to another mechanic and he solved the problem in minutes at no charge. Turns out it was just a loose heat shield that was rattling at idle. Therefore, I would check for loose fittings, clamps, etc. that are related to the A/C system. Good luck.

urbanriz

Thanks for the reply, however I don't think it its related to a loose heat shield. What I have noticed, from testing in different gears when the AC is on is that I can hear almost squeel type of noise, in particular when the car is in reverse while the foot is on the brake. Turn the AC off and its gone, now this kind of sounds like a possible belt issue perhaps? I am no mechanic but will be going by him on Thursday. Till then any other suggestions would be highly appreciated as I can mention these to him when he is checking.

BubbyNme

I have the exact same noise, just as you described. I have changed the AC compressor, both idler pulleys, the belt tensioner bearings and the belt and still have the same noise. Although, it did eliminate the belt squeal.

Please post anything you find out from your mechanic.

2GSKaizen

iTrader: (1)

I know exactly about the noise you speak of!!!!! My moms 06 rx330 had the same noise. it is a very common issue with a hard section of the AC line itself that is vibrating against either the engine, or the firewall I can't remember. The ac compressor running for some reason makes it vibrate just enough to make the noise. Now as far as a fix...... Ours was under Certified warranty. We took it back to the dealer I work at, and I had to go for 2 drives with a tech and the service manager before we could get it to make the noise..... Once the service manager heard the noise he knew exactly what it was. I think they ended up sucking out the Freon, and replacing a section of hard AC line that ran from the pump to the evaporator I think. Fixed the problem, and it's been noise free ever since! I think the part cost was about $180 for the line.

neelnaik

It sounds to me like the infamous squealing noise when the ac is on with the 3.3 liter 3mz-fe. I still haven't figured out what in the world the noise is coming from. I own both an 04 rx 330 and an 05 sienna, both with the 3mz-fe, both that have this noise. It sounds like it's a belt issue, but it's still there after replacing all of the belts and idler pulley and tensioner, so it's not a belt issue. This seems to be really widespread, as almost every 3mz I've ever been in or have heard drive by at low speeds with the ac on does this. However it sounds like 2GSKaizen has gotten to the bottom of it. I personally don't think it's annoying enough to try to get it fixed, especially if it's just a freon line that's vibrating; nor do I think it's really anything to worry about.

2GSKaizen

iTrader: (1)

I was told by our service manager that is a very common issue with both RX and Siennna's using the 3MZ-FE, He did say that he has never seen one cause a concern, other than the noise. If you are going to have to pay out of pocket for the repair, I'd try to live with the noise. If you do have some kind of warranty, it might be worth a try to have the dealer take a look.

neelnaik

@2GSKaizen, I agree with you on that. I haven't heard of it being problematic either, just a slight annoyance. Of course the reason I don't want to do anything about it is because I am way out of warranty on both, 133K on the Lex and 182K on the Sienna. I guess that means I can at least conform the issue doesn't seem to effect anything, as the ac and heaters work just fine on both.

urbanriz

Hey all .. sorry I didnt get a chance to get back. However, this weekend the mechanic finally did the job. Turns out it was the drive belt tensioner/pulley. No more noise .. ! However, he did have to take out the a/c and disconnect a lot of things to get to it as it was a tight spot to get at. Therefore, everything in the car was reset.

My question though .. now I don't know if I being paranoid or really picky with things .. but does this tensioner have anything to do with how the car picks up and uses gas? I just have a feeling like its using more gas. One more thing, when driving, is it normal to hear a faint whistling sound when pressing the gas pedal, let it go and it goes away?

Also .. today, two later, I parked in the car and now I hear a light vibration .. not from the front passenger side where the work was done but near the back. I can't figure it out. Its only when the car is in park, turned on. Sometimes the noise will go away as well.

Sorry for the many questions but I appreciate all the feedback and help

UrbanRiz

HtownBlue

Do you have a 350 or 330? The 330 does not have a tensioner pulley for the serpentine belt that operates the AC and alternator. The tension is adjusted by the bracket adjustment at the alternator on the 330. The timing belt has a tensioner pulley fwiw on the 330.
It would be HIGHLY unlikely that would effect the mileage.

As for the whistling, check for a vacuum leak somewhere. When you accelerate or,press accelerator, that creates a vacuum in the engine system. This leaking might cause that noise.

urbanriz

I have a 2007 RX 350. Thx for this info

Oh ok .. now I need to figure out where the vacuum is

gundy

Yea, probably finding the vacuum "sucks".

HtownBlue

You have several rubber tubes that connect I to the manifold and the air intake as well as the EGR VALVES. I would start the engine and open the hood. See if you hear a whistling noise coming from anywhere near the intake or manifold areas.

It might be something completely unrelated.

urbanriz

Thanks .. I tried that but since it only comes when driving and not in park its a bit hard to diagnose

On a side note .. any idea why after changing the drive belt tensioner a clicking sound can be heard when in park or stopped at a light? Sometimes its there and sometimes not. The belt was not changed at the time the tensioner was replaced.

BTW .. my a/c noise is gone for sure, looks like the tensioner did the trick.