Guys,

I have a noise coming from behind the dash when I first start the vehicle. It typically lasts about 15-20 seconds. Originally thought it was the heater core, but that would always make the noise. Then I thought blend door actuators but it happens regardless if the climate control is on or not. I was wondering if it was coming from the NAV screen but it continues way after the nav door opens and gets to the correct position. It's kind of hard to describe the sound, kind of a mixture between a heater core bubbling and a creaking noise. I tried to record it but it wasn't loud enough to capture. Any ideas?

 

Could be the power brake pump or power steering pump pressurizing the systems. Those noises are normal for a few seconds.
The brake pump comes on as soon as you turn on the car (without starting the engine).
Neither noise should be loud.

 

Check this thread on HVAC actuator noise
please let us know if this is the noise

https://www.clublexus.com/forums/sc4...l#post10862800

 

Or is it this noise?
this is the Brake Master Cylinder

You Tube

 

Go to posts 3, 9 and 10 in this thread...
is this the noise you hear?

https://www.clublexus.com/forums/sc4...from-dash.html

 

I am Voting for the Blend Door. I think the system checks their position even if the HVAC system is off. Also, your gut instinct was the heater core, which is really close to the blend door motor.

BGW is a genius though, so you definitely want to check out his recommendations. If I post 5,020 more posts, I will finally catch up with him. (And only 9000 posts to catch up with you)

 

hahahaha...you better stop Daryl...you have plenty of knowledge and have helped plenty of folks out there...you also have that Dashing thing goin for ya ;-)

 

Thank you all for taking the time to respond. I haven't had an opportunity lately to mess with this. I replaced the antenna which was making a terrible noise so I am sure now it will be a little easier to pinpoint this noise we are discussing. It's either related to stereo/nav or a blender door. I need to play around with the controls for both and try to work out which it is. I am leaning toward NAV/stereo right now as I haven't noticed any issues with heat/ac not working or blowing through the chosen vents. Will update shortly. Thanks again!

 

Well apparently I have this noise as well, which is different than the one I was previously experiencing. I tried to upload the 6 second video but apparently it's too big for Clublexus uploads...?

 

can you post a link to youtube?

 

Say I had access to Lexus service bulletins. If I did, and your noise isn't blend door or any other documented cabin noises, hypothetically I could share an instruction document regarding windshield stopper set screw intermittent rattle.

Hopefully you figure it out. UINs are annoying.

 

I have this exact noise on a 2003 sc Pretty sure its a servo on the passenger side. What did you end up doing to resolve it?

 

did you click on the link in post 5 above?

you can purchase these actuators from Rockauto for $50-$100 or repair them for $5

https://www.rockauto.com/en/catalog/...actuator,10721

this repair video is similar to the SC430…it’s really not that difficult

You Tube

 

I had the same thing on my 2009 RX350. Loud buzzing, lasting 15 seconds, when key is turned to RUN position. Turned out to be the upper servo on the driver side, mounted to the side of the heater core enclosure. Impossible to replace without removing the entire dash. With great difficulty, I was able to reach up and unplug it using a pick to pop the latch on the connector. The buzzing stopped. Obviously I understand that unplugging this servo impairs the HVAC function. La di da.