My apologies for this post in advance, I know there is lots of threads about similar things already but I'm kind of losing my mind a little here and need some direct feedback. I started hearing a tapping/knocking sound at idle in my 1HD-T. I cannot tell if it's normal or if it has always been there. I'm hoping that if I share these recordings someone might be able to say if it's worth investigating and what are some good first steps for me. This is not the random ticking that most report (I actually don't have that sound), it is in sync with the rpm and is a high pitched clicking that's sort of subtle. Sounds to be most present on the exhaust side and perhaps coming from the somewhere near the back of the head. It is actually less present if I record from underneath so I'm not thinking it's bottom end related... I have listened to earlier recordings I made of the idle and I can kind of tell it's there but maybe not as present. As well, other recordings I have found online of healthy motors kind of have a hint of this noise but it's difficult to tell. I have found recordings of piston slap, spun bearings, failed cranks shafts etc. and there is a similarity but this is obviously far more subtle, wondering if I'm hearing early signs of something failing. It has almost 200k kms at this point and this year there are replaced bebs, installed brand new injectors, new timing belt/tensioner, and adjusted the valves. There are no symptoms of anything wrong, oil pressure is normal/consistent (~30psi idle, ~70psi @2500rpm), no rough idle, no smoke, no performance issues.
Edit: engine temp does not cause any change in the sound.
Edit: engine temp does not cause any change in the sound.
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