Really annoying tbh! Why are we not getting the gasket fix in Canada when its clear most of the fixes based on this thread seem to be that.

 

Something is off in Lexus' manufacturing. The fact that an aftermarket part was incompatible and/or an independent shop replicated the problem when they probably simply torqued to spec, tells all.

 

^^ Am i misinterpreting your post? I think Fman said that the problem happened when they used the non-Lexus gasket and that the problem went away when they replaced the aftermarket gasket with the OEM ones...

 

Yes.
The shop was able to replicate the issue probably with no foreknowledge of gasket leak and with their own part. Aftermarket parts are designed and built to a specification from the manufacturer. They did not change. The fitment on the car's exhaust changed.

 

^^ I see what you mean, however, the OEM part is also the same as used by several other applications (RC F, GS F) so it is a bit baffling that these OEM gaskets work on some IS 500 with no issues and fail in some. I am wondering if they have outsourced some gasket production and those newly sourced gaskets are the one failing and obviously, it would be a random car that get these. Or something totally different...Maybe I'll stick to the weather and/or crude innuendos which the things I am best known for (lol)

 

In my (non)expert opinion, the fact that the aftermarket gaskets threw a code adds a whole new wrinkle to this issue. My original thought was a faulty gasket, since some folks had the code go away under certain circumstances, meaning certain conditions (temperature, load, etc.) would satisfy the computer's conditions for a no fault (I'm actually going through a similar issue on my current car). I'd be curious how the aftermarket gaskets were designed, if they mirrored a spec provided from Lexus, or they just coincidentally missed something that caused the fault.

 

Yes sir, that’s what I said. I re-installed the stock gaskets and the issue was corrected.
I was led to this solution because of the new cars that have had CELs due to exhaust gasket leaks. I was getting the same codes and it appears, I correctly assumed that the paper gaskets might be the cause.
🫰

 

I'm somewhat combining your post from the Picture thread where you showed your awesome new exhaust but I've been thinking about this a lot more because I'm considering a catback exhaust myself. Say that in 8 years when it comes time to smog check your car, you can't pass smog, and I'm convinced we wouldn't be able to because I actually called a couple smog places and performance exhaust shops and they all confirmed it wouldn't pass visual without that rear cat. So then you decide to switch your exhaust back to stock for the smog test. BUT, then you encounter the CEL again and it's not something you can fix yourself this time. At that point our cars are out of warranty (I think). What do we do then? Seems like a nightmare scenario. Am I thinking about this too hard?

That's where I'm struggling. Enjoy a sweet sounding V8 via an aftermarket exhaust for 8 glorious years and face the consequences later? Or just be content with the car and never have to worry about not being street legal?

 

I will say in industrial applications, a leak from a gasketed connection is installation error (e.g. loose bolting, incorrect sequencing) about 90% of the time or more. Could be an issue in the install procedure at the factory, dropped torque wrench, etc. The other plausible scenario is some misalignment of a flange or something during manufacture. That could easily affect a large number of cars but not all of them.

 

You’re overthinking this. It’s not that difficult to swap in/out the mid pipes for emissions testing if needed.
As far as the CEL goes, it’s known to be caused by a leak at the flange. Simply replacing the gaskets in those affected cars has remedied the problem. Mine was a leak from an aftermarket gasket, resulting in the same codes. All I did was reinstall the factory gaskets. They’re just gaskets, they’re easily replaced. $52 for the pair from Lexus.

There’s a simple solution to your concerns. Leave the mods with the secondary cats in place and get an “axle-back” exhaust.

 

I agree the axle back seems like the simplest solution to not have to worry about any of this. But when you say that the mid pipe could be swapped in/out easily, I'm a bit confused because wouldn't the stock midpipe not fit with the aftermarket rear pipes? Most of the time it seems they follow a different shape so you couldn't simply swap out the midpipe without re-installing the entire stock exhaust...

I just spent the past 40 minutes reading 8 years of stories about this in the IS F forum. The general conclusion was that any modified part of the exhaust will fail inspection if the tech is doing his/her job (and they usually do) and even bribing the tech barely works anymore. Seems the best chance to pass without a swap-out is to go to a "friendly" shop by word of mouth, and who knows how many of those will exist in the year 2030. It's also super interesting that most RC F owners in CA with aftermarket exhaust parts have never experienced this yet since their cars (2015+) won't be due for smog until 2023. Maybe I'll go to the RC F forum to see what they plan to do and get em riled up LOL. Jk. I'm just super curious. It's fun learning about this stuff.

 

You're correct, which is why the aftermarket gaskets throwing the code and the factory ones not is the odd part. This was an aftermarket company torquing down at the flange with a new gasket, then replacing it with a factory gasket. It adds a new variable to the mix.

 

I thought the flanges were loose.

 

I came across this video and thought this part of the clip was funny because it reminded me of our CELs.

 

Don't get me wrong, your idea to pre-order was solid that was why I looked into buying them myself. What I am calling BS is why the long 3 weeks, Amazon delivers in 2 days sometimes 1 (maybe I got spoiled by amazon prime). The OP can probably order it online and get the part in a week and cut his wait time for repair by 2/3 (although on his dime).