LS430 Vibration

[cruisermark]

I have a 04 plate LS430 with 140k+ miles on it.

It has developed an annoying vibration which is mainly felt when the engine is running but stationary

The vibration is felt from the drivers seat - its not a constant vibration - it is there all the time but the vibrations very in severity ever so slightly.

The vibrations give a thud like fell to the

It is felt in drive and in Park - hot engine revs are 800 and revs are constant so I don't think its engine or rev speed related

Could this be engine or transmission mounts? - if not would could it be.

[BigBoomer]

Sounds like a resonance vibe to me. Is it still there in Neutral too?
If you rev gently to say 2000rpm does the vibe change in frequency or go away?

Could be the air-con compressor or alternator bearings are starting to die.
Could also be the water pump.

Bad engine/trans mounts tend to make themselves known when under load, not when the motor is idling or in Neutral.

 

[cruisermark]

Thanks for the reply George.

The vibration is difficult to feel once revved - nothing is felt once the car is moving - only when stationary

Your reply has given me an idea - i'm going to try with AC on and off and see if that make a difference.

Is there any thing else I can check?

[BigBoomer]

You can listen to the alternator or compressor with the screwdriver held to your skull method.
That can pinpoint grumbling bearings.

[cruisermark]

Just to let you now I tried it with the AC on and off and it made not difference.

These are cars a so smooth and quite that any minute vibration is felt - I guess this one is so mild that a Non-Lexus driver will not know its there

I will speak to the garage when I pass by next time I pass by

[brendangeorge]

Hi Mark

It may be worth checking if you have a low speed misfire?  I had one when a valve burnt in my now extinct 430.

 

Bren

[cruisermark]

27 minutes ago, brendangeorge said:

Hi Mark

It may be worth checking if you have a low speed misfire?  I had one when a valve burnt in my now extinct 430.

 

Bren

Hi Bren how will I check this? Will it show up a code?

[GrahamG]

Just for fun get someone to blip the throttle will you watch the engine. You might see the engine react by rocking excessively if the mounts are shot.

[brendangeorge]

On 6/27/2019 at 10:08 PM, cruisermark said:

Hi Bren how will I check this? Will it show up a code?

Hi Mark
My apologies I missed your questions - I have a Rx450h now so do not check this part of the forum much.
You will hear the miss fire at low speed - I am pretty sure you will see a code - when you rev the engine the miss fire will stop becuase compression is maintained.  You will smell the problem as well.

A compression check will reveal all and it's off to the scap yard. :(.

 

[cruisermark]

HI Brendan thanks for your reply

This has been sorted after and 02 sensor change