Help! Loud pumping/pulsating noise

[kiz17]

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!

 

[kiz17]

I forgot to add car details:

Audi A3 57 plate
S Line 1.8 TFSI
97k miles

 

[SootySport]

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.

 

[kiz17]

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

 

[kiz17]

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?

 

[SootySport]

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.​

 

[kiz17]

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!

 

[Daveyonthemove]

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.

 

[kiz17]

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.

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

 

[Daveyonthemove]

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.

 

[SootySport]

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

 

[Retroman]

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

 

[Whodafunk]

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

 

[ElzLewis]

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

 

[ElzLewis]

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

 

[maxpayne]

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!

 

[kiz17]

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

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!

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.

 

[kiz17]

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

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?

 

[kiz17]

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

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!

 

[maxpayne]

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.

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.

 

[maxpayne]

HOLY **** BATMAN!
I just discovered something - the noise stops if I press the ECON button. My understanding is that the air con compressor is turned off with Econ off but the blower motor should nevertheless work (I mean otherwise where's the air in the vents coming from when I turn up the fan, which works fine). Which means that it must be compressor related?

@kiz17

 

[kiz17]

Wtf that’s weird?

I’m out tomorrow so I’ll see what happens when I press the ECON button. Mine makes the noise even when the air con isn’t on though which is a weird?

I think you’re right about pin-pointing it to the compressor. I hope it isn’t though because that’s an expensive bill...

Have you taken yours to a garage yet for their opinion?

 

[kiz17]

I’m not sure if this is worth noting, but the noise seems to come from the passenger side, but my A/C compressor, drive belt etc are all located on the drivers side?

Could this eliminate it being my compressor?

 

[Daveyonthemove]

I think the blower fan is located in the passenger footwell under the glove box.

 

[kiz17]

I think the blower fan is located in the passenger footwell under the glove box.

Thank you. If it is the AC compressor shouldn’t the noise come from the driver side?

maxpayne - I’ve just done the ECON button test in my car and the noise goes for me as well!! Does this mean it’s almost certainly the compressor? Or could it still be the blower motor?

Because, as above, I’m certain the noise comes from the passenger side but the compressor is located on drivers side.

 

[maxpayne]

The blower motor is under the glovebox.
I haven’t taken my car to the garage yet. Someone commented on my YouTube video also saying they’re seeing the same issue (or it was you haha). Between us we should find something out!

 

[kiz17]

This is the noise I get even when the air con is turned off? The noise changes when I turn the air con on, then goes back to this noise when I turn the air con back off...

In the video I’m stationery while holding the revs around 2000-2500 RPM. If I sit at idle it won’t make the noise unless I rev, so the noise only occurs if I’m accelerating.

 

[kiz17]

Quick update: I took it to a garage on Monday and they told me the noise went (of course it did ‍). The noise is constantly there.

Has any one had any luck with this yet?

 

[maxpayne]

Quick update: I took it to a garage on Monday and they told me the noise went (of course it did ‍). The noise is constantly there.

Has any one had any luck with this yet?

No progress on my side. Did you tell the garage everything, including the ECON button factor?

 

[kiz17]

Yeah I had him sit in the car and got him to press all the buttons as well as to accelerate so he can experience it all first hand. However, my noise is there even with the air con off, it just changes when I use the air con.

I explained this to the mechanic whilst he was in the car and it seemed like he was leaning towards the drive belt/pulley area as the fault, but he wasn’t 100% sure.

He said it might not be the AC compressor, and explained that the noise can be caused by the use of the AC as the load on the belts/pulleys increases, which makes sense. So maybe your ac compressor is fine - tensioner/idler pulley maybe?

My alternator failed around 8-10 weeks ago so I changed it, along with the drive belt but the noise is still there.

I’m out of ideas! I might get it booked in again and see what they find.

 

[aqibi2000]

Providing you always hear the noise, unplug the blower fan just need a 8mm socket to remove glove box to see if the noise occurs.

You can temporarily remove aux belt to isolate the compressor from being a factor.

 

[kiz17]

Providing you always hear the noise, unplug the blower fan just need a 8mm socket to remove glove box to see if the noise occurs.

You can temporarily remove aux belt to isolate the compressor from being a factor.

Thank you for the reply!

Yeah the noise is always there even with the AC/heating turned off. I was under the impression that the blower fan is only on when using the AC/heating system?

The noise sounds like it’s coming from the passenger side of the engine bay (which is the opposite side to my auxiliary belt, AC compressor etc)

So does the blower fan still spin even with the ac/heating system off?

 

[maxpayne]

As we established in the other thread this is unlikely a blower motor issue. The noise mysteriously disappears when ECON is engaged. With ECON on the blower would still be running as usual one would hope.

 

[aqibi2000]

As we established in the other thread this is unlikely a blower motor issue. The noise mysteriously disappears when ECON is engaged. With ECON on the blower would still be running as usual one would hope.

Agreed.

Verbatim:
When set to ECON mode, the A/C compressor shuts off at higher temperature than the A/C mode.
eg: if you set to A/C mode, the compressor shuts itself by reaching the Cooler to Celsius 9, but the ECON mode will shut the compressor by reaching the cooler at a higher temperature like Celsius 12. So less energy needed at the ECON mode than A/C mode.

 

[maxpayne]

Agreed.

Verbatim:
When set to ECON mode, the A/C compressor shuts off at higher temperature than the A/C mode.
eg: if you set to A/C mode, the compressor shuts itself by reaching the Cooler to Celsius 9, but the ECON mode will shut the compressor by reaching the cooler at a higher temperature like Celsius 12. So less energy needed at the ECON mode than A/C mode.

Cool. Ironically when AC is on in summer, set at low temperature and the fan high,, this noise doesn’t manifest at all.