Noise in front left engine compartment 2001 LX 470

[morededu]

Hi everyone - relatively new owner of a 2001 LX 270. Recently notice an intermittent clicking noise that lasts for about 5 seconds and sounds like something cutting on and off. Noise seems to be coming from engine compartment on drivers side behind the steering wheel.

Here's a video where I caught the noise on my drive home today (sorry the audio is not great) - noise starts at 5 seconds in and ends at 10 seconds in:

In my 30 minute commute, I hear the noise 10-15 times.

Not that worried about, but curious is something needs some lubrication or maintenance.

 

[blue254]

I have that same noise happen every now and then too. Seems to happen right after I start the truck, very curious to see what people have to say about this.

 

[DTCsk8er]

Hard to tell from the video, but here is my best guess..

These have a motor motor in the booster that helps assist when you break. They kick on from time to time (to pressurize the system), and I typically notice is right when I take off.

EDIT: here is a thread on it:
Sound coming from brake booster

 

[morededu]

Thanks - I think that may be it. I almost mentioned that it seems to happen more often when using or right after using the brake. Service history says that brake fluid flush and exchange was completed about 1-year / 15k miles ago. I read on here somewhere that it only needs to be flushed every 3 years. So I assume all is good and that's just a normal noise.