What's making this A/C noise?

[superbike7]

Not sure if this is the right place for this question, but here goes. Wife took the Mazda 5 up to Charlotte today and had the car loaded down pretty good. Three adults, one baby and a large stroller. Well while she was cruising at about 75-80 MPH she had the A/C on full blast and it wasn't on recycle, I know not smart. Well she heard a quiet screeching, whining noise, kind of like the sound brakes pads make when they need to be changed (her description). She said it stopped when she turned the A/C off. Also while the A/C was on it never stopped blowing cold and everything worked fine. I took a look at it when she got home and of course there is no noise. Any thoughts?

 

[JovaBear]

Your 5 probably has a noisy belt. I had a similar issue with my old car, '04 nissan sentra. With the a/c on, when I would start to accelerate, I would hear a loud, squeaky noise. Once I let go of the gas pedal, the sound would go away. Took the sentra to my mechanic, and it was fixed.

 

[moniz]

Clutch in the compressor could be going. Sounds like the same noise my Acura made before the A/C finally died 4 years ago. If it's not under warranty , it's gonna be pricey to replace(yes, replace, not repair!). Considering my Acura was already 10 years old, I didn't get it replaced. Get it checked out ASAP. Nothing you are doing, it's just one of those things; some will never act up, others will just go for no particular reason.

 

[mazdadude]

Had to have our compressor replaced. It failed with a screeching noise, and then a huge woosh and a white cloud of gas came out from under the hood. That was around 50k miles. Since the compressor was replaced, the air conditioning has never been able to get the car cold enough anymore. When the Mazda Tech checks it, they say it is working normal.

 

[flcruising]

Sounds like the belt to me as well. Did this happen after rain or water puddle?

 

[oaklandopen]

Im trying to figure out why its "not smart" to run the ac in regular mode as opposed to recycle (recirculate) mode. There is nothing wrong with either. one brings in fresh air the other just conditions the cabin air

simple things first, check the belt for wear and tear, then worry about the compressor

 

[5zoom]

Recirc button should be used when first starting up the car on a hot day and when behind a smokey car/bad air. The button shouldn't be used continually because it blocks off fresh air from coming into the van, thus the air can become stale if left on for a prolonged period of time. It should also never be on when trying to defrost the windows. If you have auto AC, you'll notice that most of the time the recirc button will automatically turn off after a while if you have the auto button pushed.

 

[Silentnoise713]

She said it stopped when she turned the A/C off. Also while the A/C was on it never stopped blowing cold and everything worked fine.

Does not sound like a belt issue. If it only makes the noise when the AC is on, it sounds like the AC compressor clutch bearing is bad.

http://www.polarbearinc.com/index.htm
Give these people a call and explain it to them. They can give you some steps to diagnose it and are very nice to work with. You can also send in your compressor or just the clutch disk (if it is the fault) to get a new bearing pressed in for a nominal fee. You can prob ask them to do a full analysis and rebuild the whole compressor and buy some freon/oil and fill it yourself. Not sure how handy you but personally I dislike working on AC units b/c of the high pressure and the need for specific tools. At least the newer R134 systems are better and easier to work with than the older R12.

I took a look at it when she got home and of course there is no noise. Any thoughts?

So is the problem resolved?

 

[Silentnoise713]

Clutch in the compressor could be going. Sounds like the same noise my Acura made before the A/C finally died 4 years ago. If it's not under warranty , it's gonna be pricey to replace(yes, replace, not repair!). Considering my Acura was already 10 years old, I didn't get it replaced. Get it checked out ASAP. Nothing you are doing, it's just one of those things; some will never act up, others will just go for no particular reason.

Why are you opposed to repair? When you trade in your core, it gets repaired and resold. Properly repaired units are better than some of the ‘new’ (rebuilt) units that you buy form your local auto parts store. Granted, some companies are better than others. If it is not easily repairable, that's a different issue.

Btw, it helps to turn on your AC periodically to keep the freon and oils moving as they help lubricate seals on the compressor. Moving parts also help to clear out the cob webs and dry it out parts. Bottom line, turn on your AC every now and then.

 

[superbike7]

Wow thanks for all the responses, its one of the reasons I love this forum. Well they didn't run into any rain on the way there or back so everything should have been dry. When I drove it last night I was not able to get it to make a sound. It worked fine. As for the recycle thing, I was told by a mechanic to let fresh air in when first starting the A/C on a hot day since the air outside the car is cooler than the air inside. After the air inside the car cools switch to recycle and the A/C won"t have to work as hard to cool the air. Of course on a long trip you should allow some fresh air in from time to time, but for the most part he said you should leave it on recycle.

Would you have it looked at now, even if there is no noise, or just wait and see if it comes back?

 

[thaxman]

Wow thanks for all the responses, its one of the reasons I love this forum. Well they didn't run into any rain on the way there or back so everything should have been dry. When I drove it last night I was not able to get it to make a sound. It worked fine. As for the recycle thing, I was told by a mechanic to let fresh air in when first starting the A/C on a hot day since the air outside the car is cooler than the air inside. After the air inside the car cools switch to recycle and the A/C won"t have to work as hard to cool the air. Of course on a long trip you should allow some fresh air in from time to time, but for the most part he said you should leave it on recycle.

Would you have it looked at now, even if there is no noise, or just wait and see if it comes back?

What your mechanic said. Except that if you are hauling the soccer team after a game, you should NOT use recirc!!! (puke)

 

[DKaz]

My A/C belt squeals as well in the rain, but that's because my wife dented the A/C belt cover when she ran over a parking curb. lol.

 

[oaklandopen]

^^^in that situation i think the windows should be down regardless of weather

 

[moniz]

I'm not opposed to repairing at all, it's that it in some cases, it wouldn't make $$ sense.

I was all for repairing, but for my car I was told the price involved was just a a few hundred south of replace due to labour and the "ease of repair-ability", that to me it would make more sense to replace it if I wanted to, but considering the age/mileage of the car, I didn't really want to put that much money into it.(about $3k when all said and done, considering the car was worth $5k tops at the time)

 

[flcruising]

$3k for what?

 

[Robotazky]

Start your A/C blowing fresh air with the windows cracked so that the system displaces the baking hot air in the car with outside air. Once the A/C is blowing cold, roll the windows up and hit the recirculate button. There shouldn't be any mystery to that.

My vote is on a belt that needs replacing. If the compressor is already shot, then these cars have some seriously weak links on them. The ATX, power steering, A/C, sway bar bushings, shocks, etc. Ridiculous.

 

[Silentnoise713]

I'm not opposed to repairing at all, it's that it in some cases, it wouldn't make $$ sense.
I was all for repairing, but for my car I was told the price involved was just a a few hundred south of replace due to labour and the "ease of repair-ability", that to me it would make more sense to replace it if I wanted to, but considering the age/mileage of the car, I didn't really want to put that much money into it.(about $3k when all said and done, considering the car was worth $5k tops at the time)

Ok, we are talking two different things. I was referring to DIY repairs/rebuilds and I think you are referring to paying someone to do the work. In most cases, it is not worth paying for the labor. Still $3K is steep for AC job. I hope your mechanic is a trustworthy one.

Would you have it looked at now, even if there is no noise, or just wait and see if it comes back?

Without a reproducible issue, I’m not sure what can be diagnose.?. AC does not have any type of TDC. If you feel more comfortable having it checked professionally, please do so. On another note, I wonder if it could be just the radiator fan kicking in? But now I'm just playing the guessing game.

 

[moniz]

Yes, I trust him ,as he has saved me a ton of money for as long as I've known him, but he will tell it like it is. And yes it's the labour costs that made it so expensive because of how long it would take because of how tightly packed everything is in a small engine bay, and how many parts have to be removed just to properly access the system to work on. Well beyond any backyard mechanic, which I'm not really.

 

[flcruising]

I changed the a/c compressor out on a '95 Acura 2 summers ago for a friend. Cost - $250.

 

[Silentnoise713]

I changed the a/c compressor out on a '95 Acura 2 summers ago for a friend. Cost - $250.

+1
Also, post 1994 cars are all R134 which you can buy the oil, freon, and charge kit over the counter in Walmart for less than $50-$60.
I would think the Acura community should be pretty strong as well to give you some feedback.

Here are some how-to videos on basic diagnostic and recharging the system -obviously promoted by a company trying to push their product. No relations to me.
http://www.idqusa.com/instructional_videos.html