New strange droning noise from engine bay - maybe A/C relate
Discussion
Hello guys,
my car has recently developed new odd sound. Something in engine bay started to make a droning noise, like additional fan when revving the car. Mostly noticable from 1800rpms+. It is dependant on RPMs. So my thoughts were some bearings on alternator or pulleys or maybe water pump.
However alternator gives lovely 14.0A current, water pump doesn't leak + temperature is perfectly normal and pulleys would be making chirping, squeaking or whining noises.
So I did some laboring and found out this: The sound is present when my A/C is OFF! As soon as I turn A/C ON, it stops in 2 seconds... So possibly something related with A/C? When driving with A/C on, everything is normal and works fine, cold air almost immediately.
What can that be and how costly is the fix?
Thank you in advance!
Car: BMW E46 330d
my car has recently developed new odd sound. Something in engine bay started to make a droning noise, like additional fan when revving the car. Mostly noticable from 1800rpms+. It is dependant on RPMs. So my thoughts were some bearings on alternator or pulleys or maybe water pump.
However alternator gives lovely 14.0A current, water pump doesn't leak + temperature is perfectly normal and pulleys would be making chirping, squeaking or whining noises.
So I did some laboring and found out this: The sound is present when my A/C is OFF! As soon as I turn A/C ON, it stops in 2 seconds... So possibly something related with A/C? When driving with A/C on, everything is normal and works fine, cold air almost immediately.
What can that be and how costly is the fix?
Thank you in advance!
Car: BMW E46 330d
Thanks for advice. I found out this video ( I know it's different car, but the A/C function is the same, I presume). http://youtu.be/50jvK9kM2DM?t=31s
When the A/C is off, only outer ring spins, when compressor itself (inner ring) is not moving. If I understand correctly, there is a bearing between those rings. A/C off = bearing is rotating, which makes noise. A/C on = bearing doesn't spin because clutch engages both rings at same speed.
Is this correct?
Car developed this sound a week ago. How long can it be expected to last? Could only the clutch (or it's bearing) be replaced?
When the A/C is off, only outer ring spins, when compressor itself (inner ring) is not moving. If I understand correctly, there is a bearing between those rings. A/C off = bearing is rotating, which makes noise. A/C on = bearing doesn't spin because clutch engages both rings at same speed.
Is this correct?
Car developed this sound a week ago. How long can it be expected to last? Could only the clutch (or it's bearing) be replaced?
Yeah something like that, although I've never seen a car it's that obvious on before.
I have no idea whether that particular part can have the clutch mechanism serviced independently of the compressor itself; you'd probably be best off asking in the BMW subsection (or on a marque specific forum).
I have no idea whether that particular part can have the clutch mechanism serviced independently of the compressor itself; you'd probably be best off asking in the BMW subsection (or on a marque specific forum).
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