Whistling sound when car cold ?

[Dannyboy lx470]

Hi guys have noticed over last couple days a whistling or whirling sound when car is cold and gets louder on acceleration then goes away after car is warm. I thought it may be my brake booster, but it's not happening on braking or start-up only when driving any idea vaccum leake etc no lights on dash showing thanks ?.

 

[ramangain]

Maybe your diffs are whining a bit before your diff oil warms up. Does it sound faintly like straight cut gears in a racing tranny, only much quieter?

 

[Bigsky80]

I had a similar problem with my 80 series. In my case it ended up being a cracked intake tube. Used electrical tape as a temporary fix.
Cheers,
Scot

 

[JunkCrzr89]

Exhaust leak? Mine has a good whistle from a pin hole.

 

[Dannyboy lx470]

Thanks for the replys guys will check your tips today and report back.May be exhaust leake or a manifold leake.Any ideas why it goes away when car warms up.

 

[Dannyboy lx470]

Exhaust leak? Mine has a good whistle from a pin hole.

Thanks does it go away or always constantly.

 

[JunkCrzr89]

Thanks for the replys guys will check your tips today and report back.May be exhaust leake or a manifold leake.Any ideas why it goes away when car warms up.

Exhaust heats up and the metal expands to close the hole.

 

[JunkCrzr89]

Thanks does it go away or always constantly.

Mine started out like yours but I never fixed it so the hole got bigger and now it whistles only between 2500-3500 rpms

 

[OEMGUY0720]

Possibly the secondary air injection pump.

 

[Dannyboy lx470]

Possibly the secondary air injection pump.

Thanks for the reply will it get worse and fail.

 

[Dannyboy lx470]

I had a good look today seems to be coming from around flywheel area so it may be the secondary injection pump which is under the engine cover.Anyone had experience with this.Thanks.

 

[OEMGUY0720]

Thanks for the reply will it get worse and fail.

From your description (it gets loud and eventually go away when engine warms up) sounds to me like a definite SAIS.
You can read more about it this thread, tons of info:

06/07 Air Induction Pump Failure & Bypass

Hi all, I figured I should post this in case others run into the same problem as me in the future. I bought an 06 LX470 with 96k miles last month from a Lexus dealer. Long story short, the secondary air induction system pump failed with code p2445 (Secondary Air Injection System Pump Stuck OFF...

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