Strange whistling/whining noise 97 v70 20v Topic is solved

giovannibianco · Post by **giovannibianco** » 18 Jul 2023, 11:57

Hello,

We have a rather strange noise that has just started on on 1997 V70 (B5254FS).
It could be described, by my wife, like a cheap alarm clock buzzer... whine?
Not a whistle... It does change with revs. It disappears on acceleration and is most
apparent at idle revs.

I would say that it is coming from the accessory belt end of the engine.
As a precaution I have bought a new serpentine belt and tensioner.

I have taken a short video in order to show the sound as it varies with revs.
The video is uploaded to my Proton Drive and can be found at this link:

https://drive.proton.me/urls/6Q6JEJV3K8#hnAKhlvL8

We are currently in Finland on holiday and have to drive back to France in
a few days. I am trying to figure out of there could be a big problem.

Cheers.

giovannibianco · Post by **giovannibianco** » 18 Jul 2023, 12:00

Sorry... here is the not-password protected link...

https://drive.proton.me/urls/6Q6JEJV3K8#hnAKhlvL8cdw

Post by **scot850** » 18 Jul 2023, 17:24

If you think it is something on the serpentine belt (alternator, tensioner, A/C compressor) then just remove it and see if the noise goes away. If it does then obviously something has a bad bearing. If the noise does not go away, you may have to remove the timing belt cover to check the water pump bearing is not failing or the belt tensioner or the idler bearing.

A long screwdriver used carefully and help to your ear as a stethoscope can help to hear what is making the noise.

Neil.

WhatAmIDoing · Post by **WhatAmIDoing** » 18 Jul 2023, 21:03

To me it sounds like it could be a vacuum or PCV leak. Split hoses can make a whistle / whine noise. Pull the accessory belt first and see if it goes away. Also, why does your coolant tank look empty?

Post by **abscate** » 19 Jul 2023, 09:00

Thats a vacuum leak. Do you hear how it is not linked to revs, but when you open the throttle quickly it changes? thats when manifold vacuum changes the most.

giovannibianco · Post by **giovannibianco** » 20 Jul 2023, 02:12

Hello,

Thanks for the replies! Indeed full marks to those who proposed a vacuum leak. Phew. Well, it wasn't so much a leak as a "pinch"... the rubber elbow from the intake manifold fitting buried behind/under the power steering pump had weakened to the point of pinching. As vacuum increased it got squeezed and acted like a reed on e.g. a clarinet? Now it's quite an amusing event as it's fixed with a new vacuum line. Here is a link to video demonstrating the diagnosis:

https://drive.proton.me/urls/G1RYG7XWQ0#wkmmoLYH2PFA

So now we are good to go Finland -> France. On the way back we will stop just north of Gothenburg to visit our friends and pick chanterelles. The husband is an automotive engineer who made is early career on the 900 -> 850 project and is very happy to see our beast still charging up and down the motorways of Europe. He knows all sorts of use(less/ful) things about these cars. In that region a Volvo or Saab of our vintage is nothing special.

Post by **abscate** » 20 Jul 2023, 02:44

The husband is an automotive engineer who made is early career on the 900 -> 850 project and is very happy to see our beast still charging up and down the motorways of Europe.

We would love to hear from him here, on our p80 forum!

duke1 · Post by **duke1** » 20 Jul 2023, 12:16

: ea09acdf5430f2ceb0a4fafb46a5ec5d69313789_2_429x500 (1).jpeg (35.92 KiB) Viewed 514 times

sorry couldnt resist!