Hey RX300Fun!!

Sorry it took so long to respond but I'm finally getting back to you with good news( at least from my end)!

I replaced my rear motor mount as well as my upper "dog bone" mount and my vibration at idle problem as completely vanished! ill tell you what, my rear motor mount was a big pain in the *** but at least now its fixed. I actually made a video to help out those who look at trying to replace it themselves since theres only one video on youtube currently but it doesn't go into good detail. Anyways ill try uploading it tonight and you can see how badly damaged my old mount was. When i was in idle it just allowed my motor to vibrate harshly which is what caused all my problems , including my knock sensors to go off!

I thought my knock sensors we bad, i replaced them, and the sensor was still going off

Anyways i figured out my chain reaction of problems which i fixed and it went a little like this...

My motor mounts were badly destroyed which caused a horrible vibration at idle, that vibration set off my knock sensors in my engine to go off which prompted a fault code to appear. That fault code issued my RX to go into "limp mode" which caused me to loose my 4th gear (overdrive).

I went through a full tune up to try and fix this issue i had and it turned out to be my damn motor mounts this whole time

Anyways i hope this information can help anyone down the road shed some light to possible problems they are having and what i went through.

@RX300Fun i hope you get your Rx running back in tip top shape buddy

 

Jaycee22,

That is great news for you. Unfortunately, my mounts are in excellent condition. I actually replaced the dog bone and transmission mount with OEM parts just to see if I could change the vibration. Didn't affect it at all. I have tested the front active mount using a vacuum pump and gage as well. I believe it is good. The rear mount looks as good as the the other mounts that I replaced, however perhaps I should change it out. I would LOVE to see your video on how to do this as I see that it is really a PITA as you said.

My car is throwing no codes whatsoever. It simply vibrates and drones once it warms up, and is in gear at idle.

Think I should change the rear mount???

 

Well I followed your youtube video instructions to the letter - thank you for posting by the way. Unfortunately, even with a pry bar, I could not get enough travel to remove the mount. Still had about 1/2" to wrestle with and it wasn't going to budge any further. I was close, but not close enough. Had the old loose mount in my hand but just could not get it out. Put it all back together and will have my neighbor who is a Toyota service manager replace it. If this fails to correct the problem, I will be happily getting rid of the vehicle as I have wasted enough time and money on a 15 year old car. I have never seen such a prevariously positioned engine mount. What an engineering nightmare.

When I had the mount loose, I could tell that it was in good condition however. Not like they completely destroyed mounts that you and Hancock have. As I suspected all along, mounts are not my problem. But I will make one last attempt to have that mount changed as I already purchased the part.

Have had really good luck with my Audi's and VW's so will likely be trading RX for a Q5 or similar.

 

Your stay with us (only 6 posts) was a short one and this fix was not really your problem. Hope your next choice lives up to your expectations.

RX was not built from scratch. With emphasis on mpg and improved parts, service accessibility has been compromised.

Salim

 

Sorry to hear about that my friend, as i mentioned in the video, it was not easy to do this replacement, took me several hours (about 6-8) to try and find different ways and wiggle different parts around to finally get the result i showed. I understand your frustration completely . Our Lexus RX300 held up pretty good and has given us many years of useful life ( about 12 solid years without failure). the small repairs and replacements are just temporary to hold us off for another couple years until our Tesla model 3 arrives. Our hopes is that our RX300 will last these next couple years until then. I salute Lexus for their fantastic vehicles and reliability. No car is perfect and every car needs maintenance. We are pretty satisfied with getting 190,000 miles out of this car without any major mechanic jobs. Just like anything in life, you put some love and care into things , and they last. Right now my daily driver is a 1999 BMW 328i with 250,000 miles. running this car until it blows up on me haha then moving on to an Infiniti G37S IPL . Anyways it was a pleasure talking to you and trying to tackle on this vibrations problem, this was my first thread I've ever commented on and uploaded a video to and i can't explain enough how happy i am to know that someone put my video to good use. Thank you again for your kind words and i really hope you get your Rx300 running exactly how you want it. Cheers !

 

Didn't or doesn't VW have a problem with oil sludging issues? And a long history of electrical gremlins? I wouldnt use either of those brands as a mile-marker on serviceability or longevity, never mind affordable serviceability. I love when people do that. You rip on the rx300 because you cant figure out how to replace a motor mount. And you claim to be a engineer. A pampered electrical engineer no doubt. Did you think of loosening a few other mounts before you gave up. You do realize as an engineer, the mounts are there to keep thr motor from moving. So you claim be be smarter than all the engineers who designed the Lexus rx300. You'd better contact Lexus. Im sure the are looking for your genius to keep them in top spot at JD Powers.

Just be honest and say you are looking for a reason to sell moms Lexus and you found one. Not everyone is meant to drive an SUV.

Here is a non-commercial website you can compare vehicles. I think you will find VW doesnt get much love.

www.carsurvey.org

 

The other day I met some one who parted with his RX as there was some noise source in RX and it drove him batty.

Nothing is perfect and RX is not the vehicle for every one. Come to think of it you can pick any vehicle and they will fall short [performance, comfort, cost of upkeep, ease of service, price etc].

RX300fun had a bad experience with his RX. Lets take some hurt out by CL members being nice to him.

Salim

 

Salim,

I appreciate your professionalism with your response. I don't understand the overtones of hostility from others. I guess some people just got up on the wrong side of the bed?

I am not trashing the Lexus brand by any means. But I am frustrated that a well cared for car with 90K original miles has a problem that apparently cannot be fixed. You can see the effort I am putting into this car to try to repair it, and keep it. By the way I have owned 2 ES300's, a Corolla, and a Camry in the past - so I have been very loyal to the brand. The RX was my mother's car. I want to keep it running for both practical and sentimental reasons.

I called a high volume dealer in Atlanta, who remembers when this car was launched. He admitted that he knew of the symptoms. He also said they never figured out what the fix was. Nor did they know why some of the cars did this versus others. He surmised that is could very well be my transmission acting up. I appreciated his honesty as he sounded like a good tech that had wrenched on many of these cars.

If both a Lexus dealer and a Toyota dealer cannot figure it out, what chance to do I have? I have even called Lexus corporate but they are nor help whatsoever. I am an engineer and asked to speak to one of their engineers to simply get guidance. No luck.

So, I will have Toyota change out the rear mount because it is very difficult to do as Jaycee said (my hat is off to you my friend!). And take it from there.

And yes, VW has had sludging issues (as does Toyota - even the RX). They were one of the first to launch direct injected engines and the valves, in these designs, are no longer washed by fuel flow - hence the carbon buildup. Pretty much all new DI engines are doing this. If you own a new car, there is no escape from the problem. But I have had very good reliability from VW/Audi - and of course - great performance. Lexus is a different kind of quality - but from an engineering perspective, I still give the nod to VW/Audi for pushing the innovation envelope.

 

We are on a long trip to Florida. Two days ago a rattling noise started in my 2011 RX350. The noise went away in neutral, much like other comments here.

I found that the heat shield over the muffler has broken loose from the front bolt that holds it to the chassis. I have fixed that and the RX is nice and quiet now.

Hope this is helpful,

George Brandon

 

I have this low frequency sound on idle.On drive , rear or neutral is the same.I changed all motor mounts with OEM ,no change.IAC is cleaned but no change.Now i ordered new oem IAC and will see.May be driveshaft to rear diff has bad bearing mounts.It's crazy.Tranny is fully rebuild , but converters is not touched.
What's wrong with this car......

 

Now i changed all 4 engine mounts with OEM ones.I changed IAC valve with OEM one and low idle rpm and sound is still there.It's keeping around 600-700rpm on idle.If it keeps 750 there is no bad sound.My Maf is cleaned it's showing 3mg/s on idle.Is this normal ?

 

you have to change the transmission motor mount. Part 12372-20030. When u brake it shakes cause its struggling to go forward and since the mount is bad you feel the shake. Change the engine mount while your at it.

 

Bought my 2002 rx300, 145,000 miles. AWD October 2019.(side note).....live in Charlotte, NC had to drive to Elizabethton , TN because its hard to find interior with black leather....I hate that tan crap). Anyway...... I noticed low resonance/vibration in drive at a stop. Its intermittent. At times i dont even feel the car is running. I thought this was normal. Coming from a 93 honda accord. i'm used to vibrations especially in steering wheel. Basically the only issues i had with this RX is Check Engine Light. After knock sensors and harness, vaper hose at charcoal canister, maf sensor, O2 sensor at CAT, and upper and lower A/F sensor I conquered the CEL problematic issue with the RX. And it recently passed inspection. DIdnt have to get a waiver this year. Yay!

I agree with all the previous posts about the low vibration issue. You would think being a "luxury" brand the brainy engineers wouldnt have over look this but it happens. I dont think anyone has really come up with a solution. Good luck

 

Ok I will probably get some naysayers on this but here it goes.

I chased a vibration issue at idle for a year that wasn't there when I bought my car.
As I tightened everything up things got better but it never went away.

Things that contributed to the vibration was a bad strut & old engne mounts & uneven flow from fuel injectors, etc, etc but the vbration was still there just not as bad.

In the end here is what I found- carboned up heads @ 151k miles and randomly sticking VVT's.

I did Seafoam in the intake treatment- the one on youtube that makes lots of smoke- and 2 Seafoam in the oil treatments and it helped tremendously.

 

I know this is an old thread and your probably long gone, but this is exactly my problem. wanted to know if you ever found out anything?

lol its been a long tim eand you've probably figured this out, but this is how the Stealership, all stealerships, work. they dont diagnose anything outside of what the computer tells them, and even then its just a never ending cycle of buying parts until your out of money or pissed off. your experience is not special. this is how they do it man. its sad. its sickening. its the human virus race.

how did you make out with this? my car has 181, but it didnt do this when i first got it at 135. the AWD isnt working because of the ABS , the vibration is a 4 on a scale of 10, and only when at a stop light, etc. shift into park or drive and its gone. this leads me to believe it has something to do with drive train, the idle is fine.

any luck with diagnosis?