dahiya

Hi All,

I am looking for some opinions on a strange humming sound I hear in my 2013 RX350 FWD. Here are the symptoms: -

1. Low frequency humming occurs AT 1750 RPM during acceleration. Please note the oddly specific RPM.
2. Humming sound immediately disappears if RPM goes above 1750 during acceleration.
3. There is no humming if I push the RPM at 1750 while the vehicle is in neutral or in park.
4. The speed of vehicle does not seem to matter. I can hear the hum at low speeds as well as higher - as long as RPM is at 1750.
5. Vehicle has about 35,500 miles on it and hum developed within last month or so.
6. The hum itself sounds similar to the noise an older car would make when driving in reverse.
7. Please do not recommend changing tires and/or insulation. This sound has nothing to do with either.
8. Please see attached image showing the RPM where hum occurs.

Any ideas what might be going on?

Thanks

Clutchless

It appears you should still be under warranty, and your drivetrain is certainly under warranty. I would let the dealer worry about it. At least get this issue on your service record while under warranty, even if, as I suspect they will say, there is nothing wrong.

F250

Speed/rpm related sounds and vibrations can be hard to diagnose because of the influence of various rotational velocities and vibration frequencies and all the associated harmonics, and the diagnostic effort is even more complicated when only working across the internet. Regardless, I'll give you a few of my initial thoughts which may be helpful in narrowing down your particular issue.

1) Humming noise, in my mind, points towards a bearing or bushing issue (i.e. power steering pump, mechanical joint, wheel or pulley bearing/bushing, A/C compressor bearing, alternator pulley, etc.).

2) No noise while in Neutral or Park suggests that the noise is tied to the drive line in some form or fashion (meaning that the PS pump, A/C compressor, and engine pulleys are probably not the source)

3) Drive line components-- noise only when the car is in motion - Could be CV joints, torque converter, internal transmission components, or wheel bearings, and maybe, just maybe, the radiator fan motor?


Hope that helps direct your attention to the source, and the ultimate solution.

dahiya

Thank you both. I will let the dealer take a look and I will report back with findings.

smknkeyz

What did you end up finding out?

CAC1

My 2013 RX 350 has, I believe, the very same noise since it was darn near new. The noise sounds to me to be from the transmission. It occurs right at 1700-1800 RPMs WHEN UP SHIFTING under mild acceleration. this is the very same sound one of my old Chrysler's made under the same conditions. i found out that the trans had an external valve body so hearing it was easy. I have no idea if this is the same noise. It has concerned me though I never went to the dealer about it when it was under warranty. can anyone else validate this noise? Should I be concerned? Any help would be much appreciated. Thanks

dahiya

Hi All,

Sincere apologies for the incredibly late follow up. Just in case someone is still interested - before I could take the car to dealer, the hum stopped all by itself without any intervention. It almost seems like the sound was perhaps from all that plastic (is it plastic?) cover that spans the entire engine bay and battery. It is possible that some plastic somewhere "settled in place" after few months of driving. Bottom line is that there was no mechanical problem and I never heard the hum again.


Thanks.