2000 V70R Whining/Buzzing Noise in Engine Bay

Post by **bmdubya1198** » 14 May 2019, 19:58

I was listening to it again today, noise hasn't changed at all. It usually happens just after you rev the car, once the idle normalizes I'll hear it for a couple seconds and it stops. Other times it keeps going, but it sounds very spotty... it comes and goes.

The best way I can describe it is the sound of a digital camera focusing. Almost a "spraying" sound like the fuel pump when it's priming, but it's nowhere near the fuel pump. The sound it still most noticeable right around the power steering pump and AC compressor, to the left of the intake manifold.

Post by **abscate** » 15 May 2019, 01:35

How about an intake manifold crack, which would also explain missing boost?

Post by **bmdubya1198** » 15 May 2019, 08:24

abscate wrote: 15 May 2019, 01:35 How about an intake manifold crack, which would also explain missing boost?

Ya know, I thought about that. It sounds unlikely, but with this car you never know. A smoke test should reveal that.

Post by **bmdubya1198** » 22 May 2019, 15:04

I listened for it again the other day... it sounds like it may be coming from around the turbo inlet. Very weird... it's definitely electronic whatever it is. What could be making noise back there? I've changed the PTC already and that didn't make any difference, so I don't think it's that.

I just thought it was coming from under the intake manifold due to the way sound echos in the engine bay. I'm pretty sure it's not coming from there.

It's most noticeable just after I let off the throttle when revving in neutral. Usually it'll hiss/whine for a second then stop. Other times I'll park the car and it'll just start going. I'll see if I can upload another video.

Post by **abscate** » 22 May 2019, 18:16

CVVT cam?

Post by **bmdubya1198** » 22 May 2019, 18:53

I don't think it's the cam. I checked the solenoid, but I don't think it's coming from there. I'll have to run it again with all the covers off and listen around.

Post by **erikv11** » 22 May 2019, 23:22

Exhaust manifold leak? They can tick and make some strange noises.

I see you are now thinking it is not near the belt path but removing the serp still seems like a good test.

Post by **abscate** » 23 May 2019, 04:25

Letting off throttle is highest intake vacuum condition. That’s points to a vacuum or manifold leak, at least

Post by **bmdubya1198** » 23 May 2019, 08:09

Definitely not a tick, it's more or a whine/buzz. Lemme dig up a video from a couple days ago. Hopefully you'll be able to hear it.

It would make sense to me that it's a vacuum leak thinking of the low/erratic boost issue this car is having, but it just sounds too electronic to me to be a leak.

Post by **bmdubya1198** » 23 May 2019, 08:35

Here's a video. I can hear it clearly, so hopefully everyone else will too! It's like a "pssssst psssst psssst" sound. On the video I can definitely hear it loudest in the back of the engine.