A while back, somebody had brought up an issue regarding a little "humming" noise they heard in their, POSSIBLY, differential when doing around 50 MPH with little gas. Now, the thing is I don't know weather or not my LS400 is suffering from that too; The reason is because I don't know weather what I hear could be normal engine noise, or normal exahust noise, or tranny, or differential or whatever! (keep in mind though, the noise is not that noticable at all; you'd have to listen carefully to pick it up). Not having driven any other LS400s, I can't really make a comparison between what's normal, or abnormal. So do you guys hear anything AT ALL under those circumstances, or you drive in total silence?(other than wind/tire noise). Shoot, it's kind of hard to describe the barely-audible noise. I guess humming/whining would be the best words to use. Do you hear this too?
Thanks guys

 

Could also be a bad water pump making that noise.

 

Before I forget, do you know how much a Lexus technician would charge me to ONLY take the car for a test-drive to determine this? Do they even do this service? If so, how much $? (maybe even for free, lol, i'm dreaming)

thanks again.

 

water pump was replaced in 2000 by previous owner, when car had 64000 miles, it now has 74000 miles.

 

So nobody has every taken their cars to a lexus technician for a road-test??? If yes, around how much does it cost to do just that? (just to see weather or not everything works as they were supposed to; no repairs, just road-test).

 

azari,

I've taken my '94 to my local Lexus dealer several times for items I thought were problems, but turned out to be "normal" for my vehicle. Although I didn't always agree with their diagnosis, they never charged me unless they actually performed an operation. Versus other dealerships where there is a "diagnostic fee", my Lexus dealer has always been top-notch. However, on the flip side, they more than make up for the loss of a few diagnostic fees with their inflated parts and labor charges on vehicles they actually work on.

This is just my experience and observation. Bottom line, my local dealership has always been more than willing to listen and even drive with me without charge if no work is performed, and they even let me have extended discussions with their technicians. Hopefully your local dealership will do the same ... and if I know Lexus as well as I think I do, they will.

 

i don't hear the sound at speed but rather when i'm driving very slow like in a crowded parking lot, i used to think there was a problem but i haven't had any problems yet. so i'm not gonig to worry about it.

 

I sure hope it would be for free; that would be great!!! I emailed them 2 days ago and asked them how much they would usually charge for a diagnostic road test done by a lexus technician. Oddly enough, they have NOT responded yet (after 2 days); they usually respond after a day. Have a feeling they're putting it off or something

 

azari,

I have handled interfacing with my local Lexus service by calling and asking for a service advisor, preferably one I have worked with - but they're all very capable, and setting up an appointment to take it in. They ask a few questions about the problem and then schedule a time. Very painless, and much less frustrating than waiting on an email response. I know from actual observation of these guys during a workday that they are very busy, not a lot of time. They seem to respond to phone calls and messages pretty quickly. Just my experience.

Good luck ...

 

Try turning your A/c off. The A/C compressor can hum pretty bad.

 

Thanks for replying,
but let me clarify something: To someone who sits in the car as a passenger, the car is absoloutely silent at 65MPH or so; However, being a very sensitive person, with discriminating ears, I can pick it up and barely hear it. I'm thinking maybe I'm just being too picky and everything is fine, but just for peace of mind I'd like to take it in and have them drive it at those speeds on highway and see if everything is alright.

 

You should take your car in if you think something is abnormal. Lexus dealers are supposed to be excellent in the service department in terms of listening to what you want. They'll probably do the road test for free, but if you're worried about being charged for it just ask them if there is a fee for it beforehand.

 

hey guys,
Just came back from the road-test with lexus technician for my LS400. They were extremely nice and helpful and did NOT charge me a penny. Anyways, the technician took the car in city and on highway(did 60-70MPH) and said that there was absoloutely nothing wrong with the car. He said that differential noise is a very distinct noise and if it were the case he would know right away. So he said everything is working the way it should. He made my day