Look, you and your buddies obviously are filling threads with useless comments for your own amusement, and that’s fine. Just cause I busted you on it is no reason to make false statements about my knowledge. Along those lines, you are consistent about getting it wrong: If you look further down you’ll see the mileage listed, as well as a link to the exact sound it makes. The point of this thread is to find a mechanic that has heard this on a Toyota 3 liter. So to suggest I take it to a mechanic is totally missing the point of the note. I don’t expect someone to actually figure it out from the description. It would be something a real live practicing mechanic would have experienced if they spent their time actually working on Toyota vehicles. Such a person is not readily available to me, hence the internet.
It sounds like a wristpin knock or piston slap to me.
Not that I know anything special about it, but what are the chances the noise is coming from one of the engine driven accessories – alternator, power steering pump, water pump – rather than the engine? A fair number of parts there driven at a fixed multiple of engine speed. Bearing related noises sometimes come and go.
This could be the crankshaft timing gear. If it comes loose from the crankshaft, it makes this knocking sound.
Don’t forget the flywheel. The can make knocking noises,If they are cracked or loose.
I’m just about convinced (94.4%) it’s the front catalytic converter! I’ve got a stethoscope. Now I just need to catch it in the act!
Oldwrench is the winner!
It was a craked flex plate!
It broke clean in 2 (plus a few small pieces).
Boss, How Did It Get Diagnosed Properly ? Who Did It ?
CSA
I would also like to know the answer to CSA’s questions, and additionally I would like to know the model year of this Lexus RX. The OP never did tell us that detail.
02 RX300 (same as a highlander). I took the trany out and there it was.
That’s all there was left to do. The noise had gotten so bad, and motor developed a vibration such that anyone with an once of mechanical compassion couldn’t drive it anymore Although this didn’t stop someone (who shall remain nameless) in the house from using it, as it was quite drivable.
I should mention this is not a job for the faint of heart. Also I recommend you have 2 engine hoists available for this job.