screeching noise help

[Jim33]

Hi all

Desperately hoping someone here might have had this or know what this might be!? 

My 2007 Audi A3 8P 2.0 T is making a high pitched screeching noise every now and then. It seems to only happen when the engine is fully heated up (after 20 mins of driving) and it seems to be most often just after gently accelerating, then backing off. 

Also, when I get back (engine is fully heated up), noticed that it makes the noise when i turn engine off and on. Its coming from engine bay area, but can't pinpoint where exactly.

Have 2 audio clips showing these sounds.

turning on

 

and off

 

A mechanic initially thought alternator belt slipping, so alternator, belt + tensioner / clutch was replaced, but no joy 😕

Any thoughts are appreciated. Thanks!

Jim

 

 

 

[cliffcoggin]

It sounds like a dry bearing, but beyond that I do not know.

[Magnet]

Welcome Jim and thanks for joining,

Apologies for hijacking Cliff’s responses , but I would be very wary of it being associated with a timing belt issue - tensioner maybe - although I confess I haven’t listened to it- hearing is shot.
When was the timing belt assembly and water pump last renewed? 
If you don’t know, then I would be treating this investigation with the utmost urgency. 
Kind regards,

Gareth. 

[Magnet]

Hello Jim,

Just wondering since you have re visited the forum, and we take it, read the responses so far, whether you have any comments. 
Kind regards,

Gareth. 

[Jim33]

Thanks both. 

I have paper work for timing belt change at 25k miles in 2016. It’s pretty low mileage car, it’s at 47k now, but been a while I suppose. Also does not say about water pump.

will post if I find anything.

[Magnet]

Who carried out this work Jim? Some aftermarket water pumps -and tensioners are not as good as they could be. 
As you say:- long time since 2017 ( even though relatively low mileage since).

According to VAG’s previously sound logic, it should have been changed again in 2022. Now they daftly don’t stipulate a time limit, so could be a ticking time bomb to destroyed engine. 
I would be getting it inspected - changed?- if it were mine. 
Perhaps you could let us know what you think Jim. 
Kind regards,

Gareth. 

[cliffcoggin]

Jim.

It's strange that the water pump was not renewed with the timing belt. They are normally done together because the same amount of expensive work is needed to get access to them. It is possible therefore that the water pump now needs to be replaced, though it would be worthfirst checking the alternator bearings and belt before booking the car for a pump change.

 

[Magnet]

Perhaps it went a bit like this with not changing the water pump on this particular vehicle Cliff:-  

It had only done 25k miles, and if it were mine, I wouldn’t have changed it in this case, solely based on experiencing the affects of fitting some aftermarket pumps which prove to be troublesome in a short space of time. In fact, by the same logic, I wouldn’t be in a rush to automatically change a 47K pump, but I too would want to inspect it. A new pump would have to be VAG only for me (in caps).

I’ve also been disappointed with the bearing quality on some hitherto respectable branded tensioners - rough as a badger’s whatsit. I note that that particular ‘manufacturer’ is now marketing full timing belt kits under their own brand name, so it becomes choose wisely, and for me ( again in caps) VAG pump only. 
Kind regards,

Gareth. 
 

[cliffcoggin]

I don't have your wide experience of different brands Gareth, so I would tend to take the safer option of only VAG parts despite their higher cost, particularly on this sort of job where the labour costs are very high compared to the parts costs.

[Magnet]

I think you are absolutely right on safer option Cliff. Sad to say, as far as water pumps are concerned, I pay the penalty of high dealer prices for peace of mind. If only we knew who were the OEM manufacturers! -? 
Kind regards,

Gareth. 

[Jim33]

Gareth

was done by previous owner at an audi/vw specialist (mark tempest). Would have thought they would use oem parts, not sure.

Think I’ll get that checked then. Good point on the part vs labour cost Cliff, deffo makes sense, thanks

[Magnet]

Thanks Jim,

Audi/VW specialists:- one would assume that they would only use dealer parts, but an assumption it has to be. At the opposite end of the scale, they could use ‘cheapest deal from their favourite motor factor’. 
Some main dealers used to have ‘discounted offers’ on such things a cambelt changes on older vehicles. Now?? In some cases it was cheaper to get it done at the main dealer, than at an independent. 
Beware, the dealer may well now tell you it doesn’t need changing until c125K miles ( without any time limit). 
Please let us know if we can advise you further, once you have done the basic homework. 
Kind regards,

Gareth.