Hey guys I have a 2014 with 77k. I was running pennzoil platinum 0w20 for the last 4K miles that I’ve had this car and had just changed the oil with Kirkland full synthetic 0w20. As I started it to bring it up to pressure I noticed for the first time what I believe is a valve tap.
I had a 2006 IS350 so I know these injectors are noisy but I don’t recall ever hearing this before on the GS…

here’s the video of the noise …
https://youtu.be/yUnHxcwOhJQ

thanks in advance

What I hear is the direct injector pump. It is at the back of the intake where that noise is apparently coming from. There is a thread about Lexus making a cover for that injector pump in the LS that can be retrofitted to the GS.

Here's that thread. Fuel Pump Noise Reduction

It doesn’t sound like valves are tapping more like a noisy high pressure fuel pump similar to mine. Here’s what my 200k mile 2013 GS RWD sounds like:

https://drive.google.com/file/d/1tN9...w?usp=drivesdk

Does the noise change when accelerating? I would try the HPFP insulator mod above and see if that helps.

1st thing to ask is: Do you think it was there before the oil change and you just never noticed it? I think I would have if it was there before the Oil change. I use the same Oil Pennzoil Platinum for years in all my cars. Never had that noise in my GS. Also this is a common issue with the GS and the similar Engine Tacoma. Its all over the internet. One thing some have found and had replace is the Vacuum Boost Pump. You may want to google listen and compare with your noise.

If it were me, the 1st thing I would do is drain that oil and put back in the Pennzoil for comparison and see if it still there a few days and miles later. I know that would be a pain but I would just drain and refill or drain and change the filter again just to see? Being that you think the change occurred directly after you were bringing up the pressure?

Update:
I changed the oil back to Pennzoil and drove it for about 100miles without any change as expected.
I then installed the pump cover as mentioned above and noticed that that was indeed the culprit. The 30-50% reduction is fair to say. Here are before and after videos outside the car with the hood up. Appreciate the guidance fellas

Without cover

With cover

I'm sorry but I can't tell any difference, if you do, that's cool. I'm bummed out as my 2017 sound like is low on oil, smh. I will inquire about the vacuum pump on my next oil change.