Does anyone notice a tapping sound coming from the engine of your RX? I'm not sure what it is exactly: valves, noisy injectors, etc. but it seems to be coming from the top back part of the motor and also the bottom back part of the motor (one of the accessorys?). It sounds a tiny bit louder at start up and continues while the engine is at normal operating temperature. Iv'e only used Mobile 1 synthetic 5w-30/K&N oil filter since the free oil change that Lexus did. The car is at 16K. I made an appointment for Wed. with Lexus but I just wanted to see if this is normal or unussual. We just got a new Accord and it has no tapping, plus I'm used to driving that, and just noticed the Lexus (which I don't drive much) making that noise. Do you guys think it's from the sound of the injectors that I'm not used to? Lexus said that they had a problem with the bolts, coming from the header, breaking and making an unusuall sound from a couple of RX's but I don't know if this is what I'm experiencing. Thanks for all the help

If it's a high frequency "ticking", it's noisy injectors. I can't hear the noise outside of the vehicle, yet can hear it inside the cabin with everything (except the engine) off. It has to do with the injectors hitting a certain "frequency" that the sound deadening insulation and firewall don't block.

I noticed the same thing on my RX. Sounds kinda like a quieter version of a diesel engine? I thought it was the valves, nothing abnormal, but just the way they sound. Never thought of it being the injectors. I'll listen under the hood tomorrow. I've used Mobil 5w-30 for every oil change.

-Nick

Nick-

At first I was extremely annoyed at the sound (because everyhting else about the vehicle was dead quiet!), so I took it to my original dealer. They had their lead mechanic listen to it and without flinching said it was the fuel injector solenoids clicking on and off. I said no problem and made sure my complaint wasn't written into the service record computer (the following is the reason why).

Just to prove I don't trust anything a car dealer says, I then took it to a completely different Lexus dealer. Said the same exact thing without even getting out of the vehicle to look anything up.

And since I had visited a third dealer for an oil change, I asked them. Same thing.

Apparently it's inherent in the 3.0L V6 design. Again, outside the car you can't hear a thing because other engine noises tend to cancel it out. The problem inside the cabin is that the sound deadening insulation and firewall cancel every other noise out BUT the injector noise.

I've actually caught wind of a possible fix from some Toyota discussion boards. Apparently some Toyota dealers are wrapping insulation tape around the injector solenoids to help quiet them. I'll ask the Lexus folks when I go in for 15k service if they've heard of this and to investigate.

-TC

Thanks for the infor RX300TC Glad to hear it isn't just me.

does the 1995 ES300 do the same thing?

I'm not sure (my guess is that engine is slightly different in design than today's models), but the mechanic definitely said that the 2000 & 2001 ES300s definitely make the noise. Makes sense since the RX & ES engines are almost identical

Just got back from the Lexus dealer and they told me the sound I was hearing is just the normal sound the injectors make and that it is nothing to worry about. The mechanic there also told me that upon harder take-off's the motor tends to be a little loud as is it sucks in the more air it needs. He also said that even though the ES uses the same motor their is less strain on it in the ES because it is a lighter car, so that is where some of the other noises we hear in the motor/drivetrain come from. So, no worries for now as everything seems to be fine. But hey, it was worth all the trouble...

After finding out it was gonna be an hour wait I asked the guy if I could get a loaner. He said "Let me check if we had one reserved for you." Expecting the worst as to not let myself downhe returned with the keys to a brand new silver IS300! What more could a 19 year old ask for: a nice day, an hour with a new IS, and a big grin on my face. Just goes to show that Lexus IS the best in service. When my parents sent me out to look for a new car for them two years ago, BMW and Mercedes dealerships looked at me like I was lost or something Oh well, it turned out better for us anyway

Erfan: I'm not sure if the motors are the exact same, but I am willing to bet that that is where your noise is coming from as well.

Thanks for the help