Initial Chugging noise LS430 Usually just after starting then it goes

[nartorias]

Hello everyone I am new here so really nice to be among what seems as a new family! ;-) 

I have a LS430 which I just acquired. 2002, great MOT results in that there's never been an issue and its been fully serviced/maintained, 157k on clock.

However, I noticed that sometimes when I start the car there is an "initial" chugging sound that comes from the footwell area near my feet or on that side where I am seated as the driver. It's not an overly loud sound but I have started the car many times since buying it used from a trader on Wednesday morning and now on Thursday evening (after  drive of about 240 miles) I have noticed this issue. 

The trader said it's something to do with Air Compressor  for suspension that fills up. But when I told him it's from the footwell area not the bumper area t(which he initially thought) hen he said he doesn't know. PLUS why is it the first time I am noticing this noise after many times of starting it?

Any pointers would be much appreciated. Thanks! ;-)

R Mair

 

 

 

 

 

 

 

 

 

 

 

[m4rkw]

Hey congrats, I've been looking enviously as those cars on eBay recently and wish I could get one! Unfortunately with the amount of stuff we frequently need to haul around they just aren't practical. I'm hoping when my wife's been driving for a year or two she might start coveting my RX and then I can get one hehe.

I don't know what this sound could be but perhaps posting a video might help others diagnose it for you?

[nartorias]

Thanks m4rkw I’ll try. They are amazing cars btw I highly recommend! 

[BachelorDays]

The video will help.

You could also try starting the car standing outside with the bonnet open, just to hone in on it.

If the noise comes as you turn the key, or just as it catches, it could be the starter. If it's just after the engine has fired up it could be a pulley.

[nartorias]

Thanks BachelorDays I will bear that in mind and do some observing ;-)

[steve2006]

IIRC the air suspension pump is located inside the front offside wheel arch so this could be the cause of the noise, providing the suspension is maintains height it is perfectly normal, the pump kicks in on start up to equalise the system pressure. If the set up is the same as my old Celsior if you move the height control switch to high the pump should kick in making the same noise. Another possible cause is a vacuum leak on the brake servo located behind the dash. To test this turn off the engine then pump the brake pedal until it becomes hard. Keeping your foot on the pedal start the engine, the pedal should fall slightly under your foot if all OK.

[nartorias]

Thanks steve2006 that's really useful information and much appreciated! You're clearly very knowledgeable and I will come back to you again if I need to if you don't mind. Raj ;-)

 

[The-Acre]

I've found with mine the suspension pump can seem to go for several days before I hear it kick in, or sometimes I'll hear it every other day. It's not loud, just a "burble" 

As Steve says, it's located under the drivers side wheel arch cover.

[steve2006]

A common problem with the suspension pump is that the rubber mounts wear allowing metal to metal contact which results in increased noise in the cabin.

[cruisermark]

Yes - I agree with the above.

Sometimes I wont hear mine for months then it might come on 2-3 times a week.

I must say I have never heard it come on when starting up.

One way to pinpoint the noise is flick the suspension switch to high and see f the noises matches the noise you describe

I do have a set of Brand New Blue Prints suspension mounts sitting around if interested.

You can replace them by removing the driver side wheel arch liner