So I have noticed this weird noise coming from behind the climate controls when the engine is under load, whether going up a hill or accelerating. It's more common, or louder, when the engine is cold. But engine load is by far what makes the noise appear the loudest. I can't quite replicate the noise as I have no clue what it is, but managed to record a few clips while the sound was happening.

I took it to a mechanic said it could be a worn transmission bushing, and when the drive train is under load, it moves the drive train enough to where the engine/ transmission is hitting 1 of the heat shields in the transmission tunnel and causing that sound. Sounds a bit far fetched to me, but what do yall think?

 

Hi, was fighting with the same for quite some time... It turned out to be heater core pipe vibrating in plastic clamp in the firewall - you need to remove glove box to get access.

I just put small rag in the plastic clamp and vibration stopped.

 

Do you know why the pipe is suddenly vibrating? Has it become loose somewhere or need to be tightened or something?
I dont suppose you could give me a tutorial or a guide on how to get to the pipe?

 

Heater core pipes are connected with cooling pipes in the engine, hence they always slightly move especially under engine load.
You can't tighten it as it's just a clamp that pipes go into.
Once you remove glove box put load on engine till vibration starts and then try shaking heater core pipes with your hand and see if vibration goes away.
If so, here is your issue.

Look here to remove glove box:
https://www.clublexus.com/forums/gs-...l#post10329373

This plastic clamp is marked as 8712433070 here:
https://partsouq.com/en/catalog/genu...CZ1BL9GA001442