So yesterday my classic started to produce a very fainted high pitched whistling sound. At first I thought it was a police car some distance away, because that's exactly what it sounds like - A police siren that it miles away - It's really faint and it connected to throttle action.

However, it doesn't do it when the car is standing still, only when moving, and above 2.5K - so it must be turbo related. You only notice it when driving sedatly - the turbo whine and engine noise comes of the top of it and drowns it out once you put your foot down.

I don't have a boost guage, so I don't know if I am losing any pressure - And I haven't noticed a drop in performance. It's booked in with Len at subaru4you in a couple of weeks, so I'll ask him about it when I am up there. It's definitely coming from the drivers side

In the meantime, any ideas?

 

sounds like a split boost pipe or maybe a pipe come off the manifold somewhere?

 

Yeah thats what I was thinking - I can't see any hoses off, but a split is a possbility - I guess I am going to have to wait for it to get worse before I can spot it though. I couldn't see any obvious gaping holes.

 

what year is it? have you increased the boost? if you have the hard plastic pipe from turbo to intercooler, they are prone to splitting.

 

It's a MY98 - No, boost is normal. It only started doing it Friday. Am now paranoid - as I am sure there is a high pitched whislte coming in just before the turbo spools up too - I can control the pitch of both noises with my right foot.

Can make some nice tunes, but I really would rather not to be able to

 

Did a search and found this post...

https://www.scoobynet.com/drivetrain...hlight=whistle
I do hope my turbo isn't going to give up on me

 

Argh. Just spoken to Len @ Subaru4you - From my description is does indeed sound like a turbo on its way out.

Now I just need to convince the warranty company to give me a replacement without it actually failing first.

 

Rule out the easy/cheap things first.
The MY97/98 cars have a plastic recirc valve that is prone to failure.
It cracks open too early , resulting in a high pitch "moo" or like blowing over the top of a bottle, when on boost from about 2500 - 3500 rpm.

Nick

 

Oh I am sure that Len will check the cheaper options first. But thanks for the tip.

Imagine for one second I am a lay man, and have no idea where the recirc valve is, or what it looks like, or how I would tell if it's cracked. What would you tell me to do?

 

I've had similar noise and i think it turned out to be large hose from intercooler to manifold not sealing properly.

Again I didn't seem to be loosing performance, but under boost conditions you'll only need a tiny leak to make a noise.

My noise was only on boost though. I thought it was turbo, but turrned out (I think) to be the cheap easy option.

Check all hoses and clips are tight etc... fingers crossed M8