Rx300 Noise And Vibration

[pklaus]

My 99 RX300's been making a strange sound for a while now. It does it every time the RPM's reach about 2100 and lasts through about 2300. Only happens during acceleration. It's a low humming/grunting sound. Almost sounds like it could be a vibration, but I'm not sure about that.

My best guess is that it's a vibration that comes from the exhaust system. I've heard of these cars having exhaust issues, but I don't want to tear the thing up for a noise that might be benign. The performance of the car seems fine, but the grunt/hum seems to be getting louder and longer over time.

Anyone had this problem before? Anyone know how to fix it?

Thanks!

[RX in NC]

Early RX models had a known issue with the exhaust manifolds cracking. Our previous 2000 RX300's exhaust manifold cracked at about 47,000 miles and was replaced by our local Lexus dealership under warranty back in November 2003. I wouldn't be surprised if yours is cracked and probably has been for quite some time....

Why not go to your nearest Midas location and have them inspect your entire exhaust system? It's free....

[tinujatinpatel]

My 99 RX300's been making a strange sound for a while now. It does it every time the RPM's reach about 2100 and lasts through about 2300. Only happens during acceleration. It's a low humming/grunting sound. Almost sounds like it could be a vibration, but I'm not sure about that.

My best guess is that it's a vibration that comes from the exhaust system. I've heard of these cars having exhaust issues, but I don't want to tear the thing up for a noise that might be benign. The performance of the car seems fine, but the grunt/hum seems to be getting louder and longer over time.

Anyone had this problem before? Anyone know how to fix it?

Thanks!

I have a similar problem. My car is a 1999 AWD Rx300 just as yours with 130000. It vibrates on hard acceleration and sometimes even when cruising depending on the road curvature and slight turns. When sitting in the back seat on the driver side, the noise and vibration is very loud upto about 55 miles per hour and starts to die out. I have had the first intermediate shaft drive axle from the front diff to the rear diff replaced and lost some of the vibration but not all. I know the front axles are newer than the rear. I believe the exhaust on this car is a problem as it is loud enough outside of the car.

[pauljcl]

Early RX models had a known issue with the exhaust manifolds cracking. Our previous 2000 RX300's exhaust manifold cracked at about 47,000 miles and was replaced by our local Lexus dealership under warranty back in November 2003. I wouldn't be surprised if yours is cracked and probably has been for quite some time....

Why not go to your nearest Midas location and have them inspect your entire exhaust system? It's free....

Thank you for your interesting comment. My '99RX300 recently started making a 'slight humming noise' at certain revs. (but not roughness), but had a noisier rougher idle when cold -- I thought an exhaust gasket might be the problem (but the car heats up on the way to the dealership... and I was going to address the issue when next in MI, i.e. next month). It would now seem that the cracked exhaust manifold might be a cause, particularly since I have read other posts that show it to be a weak part, prone to cracking. Do you remember which exhaust manifold it was: the 'easy' one in front or the 'hard' one in the back of the motor compartment? I could not 'see' anything visually. - Thanks!

[blk_on_blk]

I remember reading a long thread on here about cracked manifolds. If I remember correctly, a truly (meaning problematic) cracked manifold triggers codes in the ECU (probably depends on where it's cracked). Plus, if you've got a crack/leak in your manifold, which is cast and quite solid, you'd have a leak/sound/issue all throughout the RPM range, not just at certain RPMs (plus it should get worse/louder with higher RPMs due to the greater exhaust amount/flow(or reduce once the engine is hot, due to thermo-expansion))... and I doubt it would have a rattle/hum/grunt sound if it were cracked... it's more likely to have a sharp 'popping' sound.

We have a very similar vibration at about the same RPMs in our ES300, and it only occurs under load, and I'm quite sure it's exhaust related... just hitting a resonance vibration and rattling a loose mount or heat shield or something. I'd take RX_in_NC's input and have a muffler shop give you a quick check-up as a first start.

[RX in NC]

I don't remember which part of the exhaust manifold was cracked (this goes all the way back to November 2003). I had read about cracked manifolds being a persistent problem on early RXs and asked the dealership to check ours when the vehicle was in the shop for our failing transmission. They found a small manifold crack and replaced the manifold under warranty as a result. No codes were ever thrown and I didn't notice any strange noises, either. I was simply fortunate to catch the issue before it became a real problem....

So keep in mind that your manifold could indeed be in the early stages of cracking even if you are not hearing any abnormal sounds and your ECU is not throwing any codes....

[pauljcl]

I remember reading a long thread on here about cracked manifolds. If I remember correctly, a truly (meaning problematic) cracked manifold triggers codes in the ECU (probably depends on where it's cracked). Plus, if you've got a crack/leak in your manifold, which is cast and quite solid, you'd have a leak/sound/issue all throughout the RPM range, not just at certain RPMs (plus it should get worse/louder with higher RPMs due to the greater exhaust amount/flow(or reduce once the engine is hot, due to thermo-expansion))... and I doubt it would have a rattle/hum/grunt sound if it were cracked... it's more likely to have a sharp 'popping' sound.

We have a very similar vibration at about the same RPMs in our ES300, and it only occurs under load, and I'm quite sure it's exhaust related... just hitting a resonance vibration and rattling a loose mount or heat shield or something. I'd take RX_in_NC's input and have a muffler shop give you a quick check-up as a first start.

Thank you, blk_on_blk and RX_in_NC - I will follow your suggestions when I get to MI [and, blk_on_blk, I haven't forgotten that I owe you a report on the success or failure of the B&D trickle charger which - I hope - will have been working throughout single digit temperatures and five months.....]. We should be leaving Miami on May 19 or 20, so, by the end of the week after next....

[sktn77a]

I had a similar noise at "startoff" rpms in my 99 RX300 (120,000 miles). Sounded like an exhaust leak/heatshield vibration. Took it to the dealer and they diagnosed a cracked manifold. Replaced the manifold ($900) but the noise is still there.

Bottom line, be careful of this diagnosis - I don't know if the manifold really was cracked or if they just assumed it was because of the noise. I guess I'll never know!

[tinujatinpatel]

I had a similar noise at "startoff" rpms in my 99 RX300 (120,000 miles). Sounded like an exhaust leak/heatshield vibration. Took it to the dealer and they diagnosed a cracked manifold. Replaced the manifold ($900) but the noise is still there.

Bottom line, be careful of this diagnosis - I don't know if the manifold really was cracked or if they just assumed it was because of the noise. I guess I'll never know!

Well its been about 3 months now and my problem hasn't got any worse. However a ASE mechanic told me its not the differential. He thinks its the drive shafts to the diff that cause the wobble and vibration. Also I seem to have bad axles in the front with insufficient greasing. I am not sure of whether to replace them or just grease and reinsert. Also my muffler does have leak which probably is causing the noise vibration in the passenger seating area more towards the driver than towards the passenger side. I also happen to have thrown the check engine line codes P0125 and P1135. One problem right after another.

[code58]

I had a similar noise at "startoff" rpms in my 99 RX300 (120,000 miles). Sounded like an exhaust leak/heatshield vibration. Took it to the dealer and they diagnosed a cracked manifold. Replaced the manifold ($900) but the noise is still there.

Bottom line, be careful of this diagnosis - I don't know if the manifold really was cracked or if they just assumed it was because of the noise. I guess I'll never know!

Well its been about 3 months now and my problem hasn't got any worse. However a ASE mechanic told me its not the differential. He thinks its the drive shafts to the diff that cause the wobble and vibration. Also I seem to have bad axles in the front with insufficient greasing. I am not sure of whether to replace them or just grease and reinsert. Also my muffler does have leak which probably is causing the noise vibration in the passenger seating area more towards the driver than towards the passenger side. I also happen to have thrown the check engine line codes P0125 and P1135. One problem right after another.

You can grease the axle CV joints by just pulling the clamp off the large end and inserting grease. If you're having problems with them anyway, it can't hurt anything. At least try and get whatever grease they use for CV joints. They may try and sell you just regular chassis grease, but what comes with the joints is different anyway. If you can't reinstall the clamp (some take a special tool to install), you can just use a long heavy zip-tie.

Concerning the hum and vibration- a lot of people don't think about the motor mounts causing that kind of thing, but they do. I'm pretty sure the mounts on your car are hydraulic (fluid filled) and some times when they start to go bad they leak, and sometimes they can go bad without leaking, but still cause vibration and roughness (also harmonic hum in the vehicle). Use a mechanics stethoscope while someone HOLDS the brakes and runs up some RPM with it in drive and touch the mounts and listen for hum. Also in reverse.

[jmcohen23]

when ya'll say "vibrating", are you referring to the whole car, or just the steering wheel?

[tinujatinpatel]

when ya'll say "vibrating", are you referring to the whole car, or just the steering wheel?

Vibration for me is on the entire car and the steering. As I have said I seem to be having two distinct problems. Vibration occurs on certain waves of the roads if you know what I mean while driving steady and much worse when you step on it to th floor. Now sitting behind the driver you can feel the vibration on your back as long as the gas is pedal is even slightly pressed. Once you let go of the gas the vibration stops totally. This is an AWD. Sometimes I think its the muffler because when you give gas you have explosions that are loud and they vibrate the exhaust which someone transmits most of the vibration to the rear seat. Lexus told me it was the drive shafts to the diff from the front that cause the vibration and quoted me 1100 to repair. Plus now I am throwing engine codes P0125 and P1133 or P1130. I think its the air fuel meter sensor or it could be an exhaust leak but I don't know.

[blueridge]

Try taking out the air filter and fastening back the box and accelerating through the RPM range and see if the noise goes away.

[blueridge]

when ya'll say "vibrating", are you referring to the whole car, or just the steering wheel?

Vibration for me is on the entire car and the steering. As I have said I seem to be having two distinct problems. Vibration occurs on certain waves of the roads if you know what I mean while driving steady and much worse when you step on it to th floor. Now sitting behind the driver you can feel the vibration on your back as long as the gas is pedal is even slightly pressed. Once you let go of the gas the vibration stops totally. This is an AWD. Sometimes I think its the muffler because when you give gas you have explosions that are loud and they vibrate the exhaust which someone transmits most of the vibration to the rear seat. Lexus told me it was the drive shafts to the diff from the front that cause the vibration and quoted me 1100 to repair. Plus now I am throwing engine codes P0125 and P1133 or P1130. I think its the air fuel meter sensor or it could be an exhaust leak but I don't know.

P1133 and P1130 are both codes for the bank 1 sensor 1. Sometimes you can get P0125 with this if the sensor is bad and not the heater. P1135 is the code for the heater on bank 1 sensor 1.

[tinujatinpatel]

when ya'll say "vibrating", are you referring to the whole car, or just the steering wheel?

Vibration for me is on the entire car and the steering. As I have said I seem to be having two distinct problems. Vibration occurs on certain waves of the roads if you know what I mean while driving steady and much worse when you step on it to th floor. Now sitting behind the driver you can feel the vibration on your back as long as the gas is pedal is even slightly pressed. Once you let go of the gas the vibration stops totally. This is an AWD. Sometimes I think its the muffler because when you give gas you have explosions that are loud and they vibrate the exhaust which someone transmits most of the vibration to the rear seat. Lexus told me it was the drive shafts to the diff from the front that cause the vibration and quoted me 1100 to repair. Plus now I am throwing engine codes P0125 and P1133 or P1130. I think its the air fuel meter sensor or it could be an exhaust leak but I don't know.

P1133 and P1130 are both codes for the bank 1 sensor 1. Sometimes you can get P0125 with this if the sensor is bad and not the heater. P1135 is the code for the heater on bank 1 sensor 1.

Great news all. Problem has been resolved. I replaced Sensor 1 bank 1 Air fuel meter from lexus. Cost me about 240 and some change but the light is gone for about 100 miles now. It was a pain to take off on the rear exhaust manifold. I used the stuff PB blaster its great. I recommend using a 22 millimeter 6 point socket to take off the sensor. I would first remove the connector. It goes through the socket and lets you grab firmly the nut to remove. I waited about 20 -30 minutes and sprayed twice the PB blaster. Now I did have the car jacked up on all four wheels to check this vibration issue. I felt the differential and it did not vibrate at all nor did I hear any noise. However as I tapped the gas pedal to the floor I could see th diff move up and down I guess its normal. My major complaint however seems to be the exhaust. Lexus wanted $636 for a new muffler (nothing else!). I thought wow must be gold plated. Anyway will be going to the junk yards to see if I can find this exhaust. PS. I might just go ahead and replace the drive shafts from the middle to the back since lexus did troubleshoot it for me chargin me about $120.

[PaulS]

My '02 RX300 had the same vibration over 35MPH then jusy yesterday, the whole vehicle shook so I pulled over and looked under...the front drive shaft was hanging on the ground. It was broken at the u-joint where it connected to the intermediate shaft. The break caused damage to the front differential and the Toyota dealer wants to replace the entire front diff and entire drive shaft right to the rear diff for a cost of $5500. The dealer says he's seen it happen on Sienna's (they use the same drive shaft). IS this a known problem that should have been re-called or at least a tech bulletin sent to RX owners?

- Broken & Confused