sound like an airplane when aircon on

[Gerald 5]

Hi sifus,Is it normal when the engine sound like the abv mentioned when the aircon is on during idle( this is the only time I can hear it anyway), I noticed this everytime I stop the car while engine running, for exp. waiting for friend and get down for a ciggy. Have been like that since the 1st day I bought the car back in Jan 08'.When I off the aircon, then the noise level gone down. This is an e39, 530i. Please advise.

 

[afifazhanee]

That's normal I think.

 

[jeffphan]

That's not normal for A/C compressor to sound like that, but that's one of the classic problem affecting E39...sounds like whirring noise at first and will most likely get louder. Check the R134 charge level, make sure that the compressor is not overcharged. If noise still persists, that the reed valve inside the compressor is bad. I would just replace the compressor before it seizes up. Don't forget to replace the drier as well. Hasn't happen to mine yet, but I only have 50k miles in my 2002.

 

[Gerald 5]

That's not normal for A/C compressor to sound like that, but that's one of the classic problem affecting E39...sounds like whirring noise at first and will most likely get louder. Check the R134 charge level, make sure that the compressor is not overcharged. If noise still persists, that the reed valve inside the compressor is bad. I would just replace the compressor before it seizes up. Don't forget to replace the drier as well. Hasn't happen to mine yet, but I only have 50k miles in my 2002.

Thanks both for the reply, but am not too sure if it is the noise of the compressor or the cooling fan. Anyway, the car mileage is also very low, 63k for a 03'. Key checked with AB. Wonder if it has anything to do with fan clutch?

 

[jarance]

It is the sound of the auxilliary cooling fan from the other side of the radiator..

Ask somebody to OFF/ON the aircon and trace the sound of the aeroplane..

 

[azan23uk]

gerald,

If it's too loud it means that the compressor is at fault. Jeffphan was right. High pressure from the faulty compressor causes the fan to react by switching to high speed all the time. It happened to me, replaced it with a recon unit...RM900...plus gas and installation RM1,1XX. But if your A/C is working well, then it maybe something else.

 

[Gerald 5]

gerald,

If it's too loud it means that the compressor is at fault. Jeffphan was right. High pressure from the faulty compressor causes the fan to react by switching to high speed all the time. It happened to me, replaced it with a recon unit...RM900...plus gas and installation RM1,1XX. But if your A/C is working well, then it maybe something else.

Thanks for all the reply and pointer, it is just me who are not too sure whether it is normal and I believe loud is relative. My mech told me might be the radiator is due??? Anyway, I observe it again last night: Start engine in the mornng, quiet: On aircon, quiet, drove the car to the office about 10km, park the car with engine on:loud, off aircon:quiet. :stupid:
Perhaps someone with a M54B30 engine can share their engine noise.

 

[jarance]

When the engine is hot, the auxiliary fans also cut-in regarless whether the air-con is ON.
It control by temperature switch as well.

 

[azan23uk]

Gerald,

Yep. It's relative. My fan was normal speed..but one hot evening the A/C was blowing hot air. When I arrived home, i heard the fan was louder then usual. The mech checked the pressure of the compressor..it was too high...about 300...normal about 200. A/C gas also took forever to fill up. Confirmed...the compressor konk. Changed to recon unit...now back to normal.

 

[azwanb]

This is normal. If it persist for a long time then it's not. If it cuts in and out every few mins then its okay. Happens all the time on the e39

 

[alpina b5]

This is normal. If it persist for a long time then it's not. If it cuts in and out every few mins then its okay. Happens all the time on the e39

yea, when start the car, it blows at highest speed, then slowly slows down as the car cools. why can't the other carmakers do this(refering to asian carmakers... dono about audi, volkswagen , saab etc)