This is the last of my long list of noises to alleviate on this TL. Sending good karma to whoever can help or lead to a solution.

VIDEO
https://youtu.be/_fNkcXAzg_g?si=ZNnqlx0OKVQ8fzQA

ISSUE:
Upon idle when warm a noise develops (whine/whistle/unsure what it's called), stethoscope shows noise is loudest around intake manifold valleys on either side of the black denso valve/sensor on the passenger side of the Intake Manifold.

TEMP FIX
Pulling the dipstick immediately quiets the noise for 10 seconds then it returns

REPLACED PARTS
Valve cover gaskets, all intake manifold gaskets, TB gasket, EGR gasket, pcv valve (honda), pcv lines (front/back), air filter.
[Unrelated] ps pump, ac compressor, belt tensioner, serpentine belt, belt tensioner.

SERVICES
Valve adjustment

 

Problem was solved; Hole for PCV in intake hose was not drilled during manufacturing. Used a 7/16 drill bit and finished the job.

 

OEM Intake hose & tract? Seems weird that started happening 16-20 years after manufacturing.

Personally, I'm a fan of the BOV noise, it's just a bit of a PITA to actuate it.

 

This has to be an aftermarket part, and who knows how long the previous owner had this happen. I'm just happy i found it, I'll stick to having the BOV type noises on the RSX.