Intermittent taping / clicking sound (fairly loud)

Sounds is somewhere between a very loud lifter tap, and a bad main bearing. Only problem is that it comes and goes without regard to being hot, cold, A/C compressor on/off, steering wheel turned, electrical demand, Drive, neutral, moving, stopped. No correlation to any of those. It is exactly tied to engine speed. It never makes it above 2000 RPM. All exhaust and heat shield components are solid, and in place.

It’s like something about the weight of a small hammer is banging against solid metal, and fast (once per revolution). It seams to be caused from normal engine vibration. My theories are: somehow something in the gear reduction of the starter, bad bearings on the balance shafts (does it have balance shafts?). I?m out of theories. It?s definitely not a lifter as the sound is much loader under the engine than above it (with the hood open).

There are several YOUTUBE videos with this exact sound.

It is very difficult, if not impossible to properly diagnose an engine problem with just words alone. You need to take your Lexus to a good mechanic and have them check it out. You may get lucky as there are a lot of things that make a tapping noise and do no harm. On the hand…there are a lot of things that make the same noise and cause damage. See the mechanic.

Why do people post such useless replies?

Do you know whether or not it is actually inside of the engine? Have you given the motor & trans mounts a good look?

Please Give The Model Year And Tell Which Engine Is In This Lexus RX300.

Also, about how many miles are on it ?


Although It Doesn’t Say How Loud The “Ticking Noise” Is, There Is Some Information Published For Lexus Technicians.

There is a Lexus TSB (Technical Service Bulletin) for 01 - 03 RX300s addressing an engine noise.

The bulletin says, " Some customers with 2001 - 2003 model year RX300 vehicles may complain of a ticking noise from the engine compartment when the vehicle is idling. "

Apparently the noise they describe comes from the fuel injection system.

The fix is to install an updated (second) Fuel Pressure Pulsation Damper #23270-62011, together with an updated Fuel Main Tube (Pipe Sub-Assembly) #23801-20260, and four gaskets #23232-41081.

It looks like it was covered by warranty up to 48 months or 50,000 miles, whichever occured first. It shows an hour labor under warranty.


Boss, Have You Tried Probing With An Automotive Stethoscope ($15 - $20) ?

They work great in locating engine noises. Be careful. Watch out for moving and hot parts.

Give a listen to different engine components, including fuel injection lines (at fittings that are near the existing pulsation damper), especially.


Because they’re trying to help you. Missleman has correctly pointed out that these type of noises can best be tracked down hands-on by an experienced mechanic who knows what to look for. You do want this diagnosed, don’t you? You could have the noises referenced by CSA’s TSBs, you could have a loose heat shield resonating, or it could be something else.

Why are you dreaming up obtuse theories and going to YouTube instead of taking the Lexus to a mechanic?

That first post and yours are useless because they offer no new information. I even said the heat shields are ok. Do you even read the question before offering your generic "help’?
Note how the next couple of posts genuinly try to solve the problem. As for Lexus/Toyota mechanics, do you get any form of news? If you ask toyota none of there cars have any problems, not sludge build up, never any sudden acceleration, and certainly not a tapping sound! But I digress.

I have tried to rock the motor as hard as I could (not running). The mounts seem solid, and not a sound of any kind when I did that.


I don’t think you’d necessarily be able to find this out by hand. You really need the power of the engine’s torque to get things going. This means and assistant and a lot of caution, of course. But see the note about the TSB on ticking below.

Do you have any links for the youtube videos?

I think I got one of those for Christmas a ways back. I’ll see if I can’t dig that up.

I’ve run it againt the brakes in Drive and reverse with the hood up and not moving. No clunking or unusual movement of the motor.

Sounds like the tom and ray valve to me.

Ah, lecturing. I’m a bit long in the tooth to be lectured to, but hey, why not?

You asked why people post what to you are “useless replies”. I answered your question. The reply from Missileman was not useless, it was good advice. If you choose to respond with arrogance rather than appreciation, choose to pursue your own theories rather than take the advice into consideration, you’ll not inspire many to reach out to you…at least not this poster.

I know you’ll respond with a less than humble reply, so you may as well know ahead of time that it’ll be a waste of your time. I’m leaving the thread now for good.

But before I do, let me reiterate that dreaming up theories will be much less productive for you than following Missleman’s advice. But, then I’m not the one asking for help here, so it matters not to me if you ignore such good advice.

Because you give them such a useless post to begin with. You don’t give the mileage or year,you think it might be a balance shaft and don’t even know if you have them, you think it might be coming from the starter even though the starter is not engaged when the engine is running. Your theories make it clear you don’t know much about cars and we can’t hear your engine, Anyone in his right mind would tell you to take it to a mechanic.

It’s obivous you don’t need to read the posts either in order to “help”. Thanks for your valuable addition to the body of knowledge on this subject.

Not as soon as I’d hoped, but thanks anyway.

This is it exactly:

Notice how it comes and goes, and is quite loud.