Lexus gs300sel 2007 exhaust cats.

[Ken collingwood]

Hi there  my gs300sel 2007 model has the sulphur smell coming from one of the cats under hard accelleration any ideas how to stop this smell coming into the cabin area, cheers Ken.

[Britprius]

If the smell is coming into the cabin it suggests a leak in the exhaust system.

John.

[Ken collingwood]

Hi there John have you had this problem in your GS450 as i have had two GS300 both 2007 models with the same problem.

[Britprius]

15 hours ago, Ken collingwood said:

Hi there John have you had this problem in your GS450 as i have had two GS300 both 2007 models with the same problem.

Yes. When the "Y" piece started to crack due to metal fatigue, and the rear silencers rusted through on the top where it cannot be seen I got exhaust fumes in the car. This disappeared when I made and fitted a new rear section exhaust. From what I understand the pipework to the rear of the centre resonator box is also prone to rust, and leakage of exhaust gasses as are the engine to exhaust flanges at the front of the system. 
It is difficult to be more precise, but 12 years seems to be the life span of the exhaust. Although made of stainless steel it is low grade stainless, and does rust.

John.

[JeffL]

Ken and John. What mileages have your cars done? Mine's a 2007 with 72K miles.

[JerenyClarksonRocks]

Just jumping in here - I have a 2009 GS300SE, with 96K on the clock - the previous owner clearly replaced one of the offside rear exhaust parts, and now I am having to replace both cats and middle sections, due to rust - £2,000. Ouch. This is from an independent Toyota/Lexus specialist, not a Lexus main dealer. The mechanic showed me unde the car when it was on the ramp - the flange between the cat and the middle section was badly rusted, on both sides. And the middle section on one side also had a leak, which caused an engine warning light...

So they can rust away at around 10-12 years, yes.

[johnatg]

I suggest you get a quote from an exhaust fabricator - plenty of them around. They should be able to replace the rusted parts in stainless for a fraction of that price.

[steve2006]

I’ll second the above comment, seen many ads for a cat back SS system for the GS models for around £500.00.

[Britprius]

On 8/23/2019 at 5:17 PM, JeffL said:

Ken and John. What mileages have your cars done? Mine's a 2007 with 72K miles.

Sorry Jeff a bit late on the reply,
My car had done around 130,000 miles when the "Y" piece disintegrated. I feel this was as much to do with metal fatigue as it was rust. On the replacement rear section I built I reinforced the system by fitting a piece of stainless exhaust tube between the two pipes going out to the rear silencers. This tube does not carry any exhaust gas, but just ties the two rear sections of pipework together before they get to the "Y" piece. This relieves the twisting action from the weight of the rear silencers at the "Y" piece.
I will add a picture when I can next get under the car. This was an after thought, and not included in my original picks.

John.

[JeffL]

Thanks for the reply John. Still no problems with mine at 73K miles. I do garage it, don't know if that makes a difference.