LS430 2001: Exhaust noise in cabin

ThePerfectionOfLexus · February 6

Hi guys

I’ve had this beauty for almost 5 months now. During this time, I’ve started to wonder about something.

Am I supposed to hear the exhaust humming at idle inside the cabin, or should the interior be dead silent?

The humming can only be heard at idle, loudest at approximately 900 rpm. There is no humming while driving.

I know that my mufflers have been replaced at some point with aftermarket ones. This makes me wonder if they are the cause, but they have no leaks (checked at mechanic). Perhaps aftermarket aren’t that good to insulate noise.

I’ve attached two recordings (require headphones for best result).

Thanks a lot.

MaximusPrime · February 7

Hi Mario, it should generally be very quiet at idle, I would often think the engine is not even running and try to start it again haha

BigBoomer · February 7

Can't hear a thing in the interior video.
Exhaust sounds normal in the exterior video.
Are you sure it's the engine/exhaust humming and not the ventilation or radio or something else?

messi · February 7

It could the fans for heated and cooled seats

I couldnt hear nothing abnormal in the videos

ThePerfectionOfLexus · February 7

8 hours ago, MaximusPrime said:

Hi Mario, it should generally be very quiet at idle, I would often think the engine is not even running and try to start it again haha

4 hours ago, BigBoomer said:

Can't hear a thing in the interior video.
Exhaust sounds normal in the exterior video.
Are you sure it's the engine/exhaust humming and not the ventilation or radio or something else?

1 hour ago, messi said:

It could the fans for heated and cooled seats

I couldnt hear nothing abnormal in the videos

Thank you all for the reply.
Actually, I’ve turned of all accessories in the recordings. So what you hear, is actually the exhaust humming, not radio or ventilation.

I’ve read online, that I shouldn’t be able to judge if the engine is running or not on idle. That’s how quiet these cars should be. This isn’t the case with my car, since the exhaust always makes a humming noise.

The engine rpm is mostly at 900 rpm, and this is when the humming is at it worst. It’s more or less gone at 1000 rpm, and almost non noticeable below 900 rpm.

As mentioned, the previous owner had the mufflers replaced at some point. But unfortunately with aftermarket ones.

I’ve attached another recording to this post. It’s crucial to use headphones. It sounds like a small subwoofer on low frequency, hard to explain.

Do you all with LS430’s have stock mufflers to compare with?

jamesbradbury · February 7

Videos aren't very clear, the sound can't be too loud! When I had new mufflers they rubbed on the boot floor and made a noise at idle. If they are aftermarket mufflers they almost certainly won't be as quiet as oem but you'll have a hard time working it out via videos.

BigBoomer · February 8

You also have to take into account that LS430 owners are mostly older and so may be deaf as a doorpost. 😁
I know my hearing is pretty good (recent tests) but I do have very little hearing at very high frequencies and reduced hearing at some lower frequencies in one ear.
Too much of my yoof spent tuning mopeds in a closed garage and too much time spent at Heavy Metal concerts :punk:
If you are only hearing the noise at around 900rpm, then it sounds like something is resonating at that frequency and the most likely culprit for that would be the new silencers.

ThePerfectionOfLexus · February 8

18 hours ago, jamesbradbury said:

Videos aren't very clear, the sound can't be too loud! When I had new mufflers they rubbed on the boot floor and made a noise at idle. If they are aftermarket mufflers they almost certainly won't be as quiet as oem but you'll have a hard time working it out via videos.

9 hours ago, BigBoomer said:

You also have to take into account that LS430 owners are mostly older and so may be deaf as a doorpost. 😁
I know my hearing is pretty good (recent tests) but I do have very little hearing at very high frequencies and reduced hearing at some lower frequencies in one ear.
Too much of my yoof spent tuning mopeds in a closed garage and too much time spent at Heavy Metal concerts
If you are only hearing the noise at around 900rpm, then it sounds like something is resonating at that frequency and the most likely culprit for that would be the new silencers.

No, the sound isn’t too loud. But it made me curious, reading about other owners not being able to tell, if the engine is running on idle. I’m kind of a perfectionist, and this LS really deserves the best.

I had a shop investigate both mufflers last year when they did the timing belt and water pump. I was told, that the mufflers are aftermarket, but they didn’t leak. They were installed correctly by previous owner. I believe they are just not dead silent as stock mufflers.

Will have to check out, how much it would cost to replace to stock mufflers.