LS430 bug in the exhaust system

rz1c13 · January 23, 2018

Hi there,

Last summer, just after I bought my LS, I discovered that one of the exhaust pipes didn't blow as strong as the other. The difference was quite significant. At first I panicked a bit, but a quick inspection LED me to discover a leak in the right back box, precisely its bottom wall, centrally located around half way length-wise. It was big enough. The corrosion was pretty bad, so I decided to get a new one.

I wanted the best solution, and thought that I should get it from Lexus, (a ton of money) or if from any other shop, it should be as close as possible to the original. The search was long an painful, and I was giving up when found a small (home business) manufacturer in Poland. They are making all kinds of custom-made muffler replacements. I pre-ordered and in less than two weeks I had both of my boxes delivered - brand spanking new as shown on the picture.

I also had a chat about my problem with the engineer from that company, who said that LS430 back box has a built-in design flaw, and that's why they all corrode and screw you up always in the same way.

Not waiting any longer I grabbed an angle grinder and the results you see on the pictures.

As it turns out, the mid-section wall has a flap on a metal spring. This spring gets exposed to pretty corrosive environment (water, and temperature), and you don't have to wait very long (I wonder how long) before it's so corroded that the flap cannot open any more. This leads ( you can guess) to excessive exhaust gass back-pressure build up, which is not very nice for the engine nor it is good for the performance. My flap was quite badly stuck closed, which also leads to excess water accumulation in the compartment before the flat, which in turns causes the bottom of the box corrode all the way through.

On the finishing note, I am happy the new boxes do not have that annoying flap, the car runs nice and quiet, so far no problems. What I discovered in this case is to me an example of typical blind over-engineering, without thinking through about materials, the environment they are working in and the consequences.

Had I gotten my brand new boxes from Lexus (for an astronomical price) , I would have had the same problem back in a few years soon....

Regards

The-Acre · January 24, 2018

Very interesting, thanks! Can I ask how much you paid?

Malc · January 24, 2018

was the original stainless steel ?

Malc

rz1c13 · January 24, 2018

Yes, I believe the original was factory fitted exhaust. Also, the car is full dealer service history, and there is nowhere mentioned that the boxes were replaced. Mine is 2004 so 13 years+ not bad, but I think if it wasn't for that stupid flap it would have lasted much longer.

rz1c13 · January 24, 2018

4 hours ago, The-Acre said:

Very interesting, thanks! Can I ask how much you paid?

500 PLN for the two incl delivery. That should be a bit more than 100 GBP, but it was in Poland, domestic delivery.

I found they do ship to the UK and the EU

https://www.ebay.co.uk/itm/Exhaust-Rear-Silencer-Muffler-LEXUS-LS-430-4-3-V8-32V-00-06r-PAIR-L-R-Black-/112440134007?hash=item1a2df44977

Chris Skelton · January 24, 2018

Best string of 2018!

ambermarine · January 24, 2018

3 hours ago, Malc said:

Malc

Interesting that the box is S/S but the pipes are not I wonder if this is the same in the 400s.

ambermarine · January 24, 2018

37 minutes ago, rz1c13 said:

500 PLN for the two incl delivery. That should be a bit more than 100 GBP, but it was in Poland, domestic delivery.

I found they do ship to the UK and the EU

https://www.ebay.co.uk/itm/Exhaust-Rear-Silencer-Muffler-LEXUS-LS-430-4-3-V8-32V-00-06r-PAIR-L-R-Black-/112440134007?hash=item1a2df44977

That is an amazing price even if the construction is not stainless at that price you could replace every four years and still be quids in on stainless from Lexus.

cruisermark · January 24, 2018

Hi

That is a very good price - would you say they are as quite as the original boxes? and how well did they match up when fitting?

rz1c13 · January 24, 2018

1 hour ago, ambermarine said:

That is an amazing price even if the construction is not stainless at that price you could replace every four years and still be quids in on stainless from Lexus.

The manufacturer says the material is aluminium-coated steel. On average, mufflers from that factory have good opinion on Polish forums. I'm guessing it all depends on the quality of the coating and its thickness. Also makes me think if the coating is applied inside and outside, or just outside... Time will tell. I'll definitely report if I see any problems.

I almost bought genuine Lexus ones, but some intuition told me to think critically and open the old box. Now I know that the Lexus design is screwed up, so I wouldn't buy that exhaust (made by Lexus) unless they start making it from gold! To be honest their price is such as if it was made out of gold... Otherwise the spring flap will corrode and you end-up backwards - what's the point?

rz1c13 · January 24, 2018

1 hour ago, cruisermark said:

Hi

That is a very good price - would you say they are as quite as the original boxes? and how well did they match up when fitting?

Hi,

Definitely the car is more quiet than it was. To make an honest comparison you'd need another LS430 with a genuine and PROPERLY working Lexus exhaust - which may now be difficult to find. IMHO the car is silent as a mouse, I can only hear a short gentle growl on harder accelerations and that's it.

The fitting was straight and easy, no mods required. The only difference is that on the new one, the end pipe ( finishing with the chrome piece) is straight, whereas in the original it is slightly bent - but that still is within the tolerance¸ so it all comes out nicely through the cut-outs in the rear bumper.

Aesthetically, IMO, the original exhaust with the elliptical spouts looks nicer. I got mine, as you see on the pictures, with those round chrome bits, so I had to forget about the spouts, or cut off the chrome pieces and attach the old spouts. I didn't have time to bother, and wanted the car on road asap.

GrahamG · January 24, 2018

Outstandingly informative post......thanks

Stakka · July 26, 2023

On 1/24/2018 at 12:06 AM, rz1c13 said:

Hi there,

Last summer, just after I bought my LS, I discovered that one of the exhaust pipes didn't blow as strong as the other. The difference was quite significant. At first I panicked a bit, but a quick inspection led me to discover a leak in the right back box, precisely its bottom wall, centrally located around half way length-wise. It was big enough. The corrosion was pretty bad, so I decided to get a new one.

I wanted the best solution, and thought that I should get it from Lexus, (a ton of money) or if from any other shop, it should be as close as possible to the original. The search was long an painful, and I was giving up when found a small (home business) manufacturer in Poland. They are making all kinds of custom-made muffler replacements. I pre-ordered and in less than two weeks I had both of my boxes delivered - brand spanking new as shown on the picture.

I also had a chat about my problem with the engineer from that company, who said that LS430 back box has a built-in design flaw, and that's why they all corrode and screw you up always in the same way.

Not waiting any longer I grabbed an angle grinder and the results you see on the pictures.

As it turns out, the mid-section wall has a flap on a metal spring. This spring gets exposed to pretty corrosive environment (water, and temperature), and you don't have to wait very long (I wonder how long) before it's so corroded that the flap cannot open any more. This leads ( you can guess) to excessive exhaust gass back-pressure build up, which is not very nice for the engine nor it is good for the performance. My flap was quite badly stuck closed, which also leads to excess water accumulation in the compartment before the flat, which in turns causes the bottom of the box corrode all the way through.

On the finishing note, I am happy the new boxes do not have that annoying flap, the car runs nice and quiet, so far no problems. What I discovered in this case is to me an example of typical blind over-engineering, without thinking through about materials, the environment they are working in and the consequences.

Had I gotten my brand new boxes from Lexus (for an astronomical price) , I would have had the same problem back in a few years soon....

Regards

Can you please provide the contact details of this company from Poland?

steve2006 · July 26, 2023

Hi Frank and welcome to the LOC.

These look the same but UK based ( price has increased obviously!)

https://tinyurl.com/3xuk7ef3

Stakka · July 27, 2023

23 hours ago, steve2006 said:

Hi Frank and welcome to the LOC.

These look the same but UK based ( price has increased obviously!)

https://tinyurl.com/3xuk7ef3

Thank you! I would like to get contacts of this manufacturer in Poland.