Another Update: After my 10K maintance, the master tech confirmed the noise (buzzing/humming noise). Tech concluded that the noise was caused due to a bad "vacuum regulator valve." Part was ordered and replace and the noise was gone. Problem fixed...at least it seemed like it was solved. Fast forward to today and another 10K miles (20K total), and the noise is back again.

At my 20K mainanace service, ask the same tech to look into the noise again. At first, he had hard time hearing the specific humming/buzzing noise until I replicated the noise and opened the hood. Yep, it was the vacuum valve again. Tech mentioned that this valve is being monitored by corporate (i.e., watch list). So far, there has been limited reports on this valve from other Lexus service departments. Not sure if 1) NX owners are not having the same issue, 2) owners are assumming the buzzing is normal engine noise, or 3) the noise isn't annoying enought to other NX owners.

 

Do you know which vacuum regulator valve, any part number on your work order?

 

Part #: 25819-0W010

 

Does anyone know what this vacuum valve does? Sure sounds like a heat shield on the exhaust somewhere is vibrating. Was going to put my NX on wheel ramps and start it up and listen with a probe. I like everything about my NX but the engine noise. As I started this thread with the thought that seems a little much for a 50K vehicle to have this kind of vibrating noise.

 

See https://www.clublexus.com/forums/nx-...ml#post9951417

 

So wondering if I roll into the dealer will they replace it upon my compliant. Is there any source of documentation from Lexus that this parts is suspect. I have complained about the noisy motor during routine maintance but the reponce is always "oh yea I have a Toyota 4 cylinder and its noisy too". I'm not very trusting of stealerships. Only reason I returned was for a free oil change which i'm wondering if they even did that. The punk put my seat all the way forward and it almost broke my legs getting in. So does Lexus posted any bulletins about this part?

 

No official bulletins, so doubt if they will replace based on a complaint of a noisy engine. Lexus is aware, but it's unofficial. My guess is, unless there are a statistical number of NX owners having the same specific issues, there will not be a offical bulletin. I got the similar response that it's just a "noisy 4 cylinder" engine, until finally, I was able to have a Master Tech look my NX. Once I replicated and specified the issue/noise, the M.Tech acknowledged that the noise was not normal.

My valve has been replaced once already, so when I went back to the same M. Tech again, he actually reached back behind the engine and was able to turn off the valve while the engine was running. Suddenly, the buzzing/humming noise was gone. "Yep, it's that valve again."

 

Do anyone have a location picture this part? Also how did the tech disconnect?

Thanks

 

No clue, but I'm not sure if you should do this yourself. After he turned off the valve, he had to re-connect the car to a computer to fix all the diagnostic errors.

 

The valve is located behind the valve cover, facing the firewall, on the passenger side. You can probably unplug the vacuum hose that feeds the valve to test, not sure if you will trigger any code though.

 

Hi all...just found this thread. I've made my own post but will post here as well. I am also experiencing the humming noise as described by OP. Occurs when I'm at idle or driving. Going to the dealer to have them check it out tomorrow. I also recorded a video of the noise....seems to be coming from the passenger side.

 

Hey I’m experiencing the same problem and noises at 25600 miles. I took the car in today and they said that since they couldn’t replicate the noise, there’s no way for them to diagnose anything. I, myself, don’t even know how to replicate the sound. It kind of just comes and goes randomly. Have you had any traction on getting anything fixed when you brought yours in?

 

I played the YouTube for order writer since it sounded like my sound. She called tech over, went to car, and it was making the noise.
Dealer called Lexus, they said to replace vacuum valve.
They kept NX overnight since they wanted to test in morning while cold.
Resolved.

 

Geez I wonder why they wouldn’t accept my video recordings as substantial evidence of the noise. They ended up sending me home and telling me to come back when I can reproduce the noise... I even played the videos posted on this thread too. Do you do anything in particular to trigger the sound?

 

Nope. Just lucky. Not convinced the sound was there when leaving garage.
But it was always present upon returning to garage.
So I assume the noise was triggered by warmer engine, not sure.
Radio is always didn’t notice it readily.