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Help! Loud pumping/pulsating noise

kiz17 Nov 10, 2018 at 11:05 AM

  1. kiz17

    kiz17 Member

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    Hi all

    Over the past couple of months I’ve noticed a very annoying and loud pumping/pulsating noise coming from my engine bay. I’ve attached a video of the noise, you may need to put it at full volume to hear it properly.

    It’s like a pumping/pulsating noise, kind of like a slow “wob, wob, wob, wob” It sounds like a pump to me? Or like something is struggling.

    The weird thing is, it can change pitch and loudness depending on if I have the aircon/heating on...? Sometimes the noise only occurs if I turn the air con on, then when I turn the aircon off it goes. And vice versa. Other time the noise can be heard at all times.

    It’s getting a lot louder which is why I’m concerned. Could it be the water pump or something major?

    The noise is so much louder in 1st & 2nd gear and gets louder as revs increase. It’s not so noticeable in 3rd gear and above (although it can still be heard)

    The car temp always sits at 90c, however when I access the onboard computer to check oil temperature, a lot of the time it’s between 100c-105c - could this be related to the noise?



    Thank you for reading, as always I’d super appreciate any help!
     
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  3. kiz17

    kiz17 Member

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    I forgot to add car details:

    Audi A3 57 plate
    S Line 1.8 TFSI
    97k miles
     
  4. SootySport

    SootySport Well-Known Member Team Silver

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    Your oil temperature is ok.
    Noise needs to be localised more accurately. The a/c compressor is a likely candidate by what you say. Check the auxiliary drive belt that turns the a/c compressor and alternator first, it may be frayed.
     
  5. kiz17

    kiz17 Member

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    Thanks for the reply!

    I’m glad the oil temperature is ok. I was worried why the needle always says 90c but the computer reads 100c-105c.

    I’ve recently (6-8 weeks ago) replaced the alternator and drive belt as my battery charging light came on. I would say it rules that out, unless the noise somehow caused my alternator to fail?

    Sometimes I will drive the car without touching the aircon/heating and the loud pumping noise is still there. Could it be the tensioner pulley? Or power steering pump as I do get creaking when turning right at slow speeds. However, the creak sounds more like a top mount but it could be related.

    Thanks again for the reply
     
  6. kiz17

    kiz17 Member

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    Also if it was the a/c compressor and it fails, could that cause major issues? Like if a cambelt snaps you’re screwed - is it the same when an a/c compressor fails?
     
  7. SootySport

    SootySport Well-Known Member Team Silver

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    It’s a coolant gauge in the dash not oil, 90 is bang on what it should be. Oil temp is shown in the OBD and some Satnav units.
    The steering is electric powered so no hydraulics to worry about, that said electric racks are can give strange noises as well.
    I can’t hear anything untoward in video. Try and pinpoint the noise to wheel speed, engine speed or just when you use the steering wheel, there’s a multitude of possible faults to eliminate.​
     
  8. kiz17

    kiz17 Member

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    Ohhhh that’s why the readings are different, it makes sense now! I thought the gauge and computer readings were for the same thing ‍♂️

    It sounds like it’s coming from the right side of the engine bay, which is the opposite side to the drive belt, alternator etc.

    You have to have the volume right up to hear it properly, the video doesn’t really pick it up that well - it’s a lot louder in person.

    I want to take it to a garage but I just know once I get there it probably won’t make the noise!
     
  9. Daveyonthemove

    Daveyonthemove Well-Known Member Team Phantom TFSI Owners Group VCDS Map User Audi S3 quattro Manual

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    Do you have anything running in the car while this noise occurs?
    Heated seats, lights, Aircon etc. All of these things will put a load on the alternator and the engine tone will change as a result.
    Try turning off everything and checking again.
     
  10. kiz17

    kiz17 Member

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    No sometimes the only thing that’ll be running in the car is the radio and it’ll still make the noise - it’s so weird but it definitely doesn’t sound right.

    Although I would say it gets worse when I use the air con/heating - the noise is more pronounced. Then when I turn the aircon/heating off the noise continues (it continues at a different tone I should add)

    Do you suspect it’s something to do with my alternator? I’ve only just changed it 6-8 weeks ago, could it be something to do with voltage circulation? The alternator read circa 14.5v after I changed it
     
  11. Daveyonthemove

    Daveyonthemove Well-Known Member Team Phantom TFSI Owners Group VCDS Map User Audi S3 quattro Manual

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    I wasn't thinking the alternator had a problem, I wondered if you had considered the extra load causing the noise and those reasons hadn't occurred to you.
     
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  13. SootySport

    SootySport Well-Known Member Team Silver

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    Have you checked the plastic under tray has all the fixing screws secure. They can flap about in the wind and cause strange noises.
     
  14. Retroman

    Retroman Audi A3 2010 Sportback 2.0 TDI 170 (CBBB engine)

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    Does the noise occur when the car is stationary or on the move. As a general rule of thumb:-
    1) Failed, wheel bearings rumble and gradually get noisier over time and with speed
    2) Bearings on alternators, tensioners, pumps, idlers etc tend to either squeak and/or make higher pitched chirping noises.
    3) Faulty power steering mechanisms tend to make strange noises when the steering is moved (even slightly) and often this noise diminishes or disappears if both the front wheels are jacked up (and then the steering moved) because the load is removed from the mechanism.
    4) I have known cheaper (remanufactured) alternators make a slight "roaring" noise and fail inside a year. I tend to favour OE or Lucas.

    97K is the sort of mileage at which OE water pumps and bearings can get troublesome
     
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  15. Whodafunk

    Whodafunk Active Member

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    Check your tension on the belt, has the belt been put back on too tightly?
     
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  16. ElzLewis

    ElzLewis Active Member

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    Mine makes this exact noise and always has in the 8 months I have had it ..
    Iv had the timing chain and tensioner done..
    Cam follower replaced
    Cambelt was done last year at Audi
    Haldex serviced
    Inlets cleaned
    ( not because of this noise )
    But as you say does sound like a pump of some sort so I just presume it’s something doing it’s job?sometimes I never notice it then other times my ears fixate on it
     
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  17. ElzLewis

    ElzLewis Active Member

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    Upon reflection and listening to the video again.. mine isn’t as noticeable/loud and mines a 2.0tfsi
     
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  18. maxpayne

    maxpayne Active Member

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    Is it like this?



    Could be the blower motor. Only happens in mine with the heating turned on.
    I took it out and oiled it and didn’t make much difference. Probably needs replacing!
     
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  19. kiz17

    kiz17 Member

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    Thank you to everyone who has replied! I haven’t been getting email notifications when someone replies so I’ve only just seen this.

    Yes it’s very similar to this!! I noticed yours slightly changes with revs, mine does too. Is yours definitly the blower motor?

    Mine is more prevalent with aircon on, but the noise can still be heard with the air con off.
     
  20. kiz17

    kiz17 Member

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    Thank you for such a detailed replied! I don’t think it’s 1, 2 or 4 (I bought a Lucas brand new)

    It could be 3, my steering can feel a bit sticky at times, it doesn’t feel as smooth as my previous A3. However the noise is apparent even when idle and with the handbrake on, so I’m not sure if it can be the power steering pump?
     
  21. kiz17

    kiz17 Member

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    Thanks for this reply, I’m not so worried now, if after all the work you’ve done the noise is still there I’m hoping it is just something doing it’s job!
     
  22. maxpayne

    maxpayne Active Member

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    Actually, I’m not sure. I took it out and oiled one part of the bearing and it seems that it improved things a bit. But I still can’t conclude that it was the root case unless I replace the motor with a brand new one.

    You should try doing the same and see if it helps. The only hassle is taking the glove box off, the motor comes out easily. See my post on this from a couple of weeks ago.
     

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