metsno1

Hey All....First post, so be gentle. I've been searching extensively but haven't been able to come up with an answer. I'm not a high-performance guy, or even a car/Lexus enthusiast, other than to say that I love my LS and want to keep her running as long as possible. She has about 145K right now. I bought it three years ago with about 92K on it. It's been essentially trouble free since that time and is a pleasure to drive, even in Upstate New York snow and ice.

The current issue is regarding the exhaust. Specifically, it appears that the Y-pipe is rotted and I'm getting some noise from that area, and it's throwing the typical cat codes. I brought it to a local independent shop (who is typically really good/flexible/trustworthy), and they said that they could not find a non-Toyota replacement for the front y-pipe, and that it would be close to $1K from a dealer. I was pretty sure I'd be able to find a replacement for a lot less (and they're perfectly fine with me finding my own part).

I found a part from Benchmark (Part # BEN4613Z) that sells for between $200 and $225, and is supposed to be an OEM fit.

But.......

Sent a link to the guys at the shop so they could see it and compare to make sure I was getting the right thing. They said that the pipe that's currently on the car doesn't look much like the part I sent them, that there was no resonator present, and that the pipes were straighter (sort of what I saw on a diagram from Walker for a 96-97 y-pipe).

Just to make things interesting, I have a receipt for work done by a Lexus dealer in Albany on this vehicle at about 77K miles (before I owned it). It indicates that the cat was replaced at that time. I'm wondering if they just went ahead and put an older version of the y-pipe on the car. The car was previously owned by a very wealthy, and seriously old widow who would never have even thought to ask questions.

So I'm wondering a few things: Was there more than one OEM version of the Y-pipe specifically used on 2000 LS's? Do I have some sort of late production model where they used a straighter version of the pipe without a resonator? Or does this definitely sound like an after-market piece that was put on when the cat was replaced?

And what's my best bet? Go ahead and replace the parts that are on it with a direct fit from Benchmark? Or is there a better (read: cheaper that will work just fine) way? I'm not really concerned about increasing performance. I just want it quiet and ready to pass inspection by not throwing any more O2 or cat codes.

Thanks!

sha4000

iTrader: (1)

Watching and waiting for the experts to chime in on this one. Its seems that at least in NY with the snow and the salt that this is a common problem on the Lexus. At least that was what the guy at the muffler shop told me. I mean he knew where the noise was coming from immediately while I was pretty sure it was somewhere else. He cut my pipe and welded a piece on the left side just to find out i had another small hole on the right side of the Y. The whole thing looked rusted to h*** and my first thought was that I would have to change the whole thing eventually.

timmy0tool

iTrader: (7)

what codes do you have? if any piping AFTER the cat and downstream o2 sensors are rusted out, it should NOT throw any trouble codes. you may have more problems than just the y-pipes.

the cats on our cars last the lifetime of the car and rarely need replacing other than rust corrosion. according to sewell lexus parts, there is a part number difference on the cats between 98 and 00.

98:
http://lexus.sewellparts.com/oem-cat...S400-1998.html

00:
http://lexus.sewellparts.com/oem-cat...S400-2000.html

the rest of the exhaust (y-pipe and mufflers) are all the same!

PureDrifter

iTrader: (10)

I live in california and know nothing of this "rust" phenomenon you speak of.

sha4000

iTrader: (1)

http://www.lexussouthatlantaparts.co...741050220.html

metsno1

OK, so I'm slowly making progress, but have a few other questions.

I've been able to order a new, after market y-pipe, plus all of the appropriate gaskets/bolts/clamps.

My mechanic is saying that he doesn't think he can get the current O2 sensors out of the rusted y-pipe without breaking them, so I'm going to order them as well.

I'm considering ordering Bosch O2's. Am I setting myself for problems by not going with actual Lexus parts?

And secondly, the mechanic is indicating that these sensors require the "interior" installation process-pulling back the carpet, getting the gas pedal out of the way, etc. But that doesn't make sense to me. If the y-pipe is going to be removed and replaced, can't the new sensors just get put in place before the y-pipe gets installed and then clip the connectors together?

Or is my question an indication that I have no idea what I'm talking about (which is distinctly possible!!)?

Thanks!

LScowboyLS

why not go with the real original Lexus parts, they are Denso brand and probably cheaper than the less desirable Bosch if purchased at amazon

$44 upstream sensors at amazon

$52 downstream sensors at amazon

cobalt91

The thing about the o2 sensors is the connections are inside the car.

metsno1

OK, that makes sense. I think I'm doing alright cost-wise. The mechanic has quoted me about $300 to replace the y-pipe and the O2 sensors. I've gotten all the parts for about $300 (and that will include the original O2's above-thanks LScowboyLS). So for an original estimate of about $1700, I think I'm doing OK!

Now I just have to hope that the lower parts of the exhaust hold up for a while!! I need to move south! Rust sucks.

LScowboyLS

so how many O2 sensors did you buy total? four?

the downstream ones are not critical if you do not have emissions testing, their only purpose is to rat you out!

metsno1

I think I only need the upstream ones, and the downstream are OK. But I live in NY, so yup, we have to pass the computerized emissions test.

sha4000

iTrader: (1)

Can we get a pic of the aftermarket Y-pipe?

metsno1

So, I managed to get an aftermarket y-pipe as I mentioned above. It needed some very minor modification to fit, and that was done at a custom muffler shop. My total cost for modification and installation was $230. The part cost $145 (including shipping). The two current O2 sensors were perfectly fine and did not require replacement. And I bought the clamps/bolts/sleeve from Seward for about $60. So I went from an initial estimate of $1700 (plus) to a final cost of $435 plus another $90 that I paid for a diagnosis to another shop earlier in the process. Not bad at all.

Here's a link to the non-California version of the part that I bought:

http://www.ebay.com/itm/Benchmark-BEN4613Z-Y-PIPE-WITH-Resonator-No-Converter-Lexus-LS400-/181312035005?fits=Make%3ALexus%7CModel%3ALS400
They also make a version of it that meets California (and now NY) standards, which is the one I bought. It's slightly less expensive.

The modification that needed to be done is pretty simple. The long end of the pipe (after the resonator), for some reason, is flanged where it should be perfectly straight. The shop cut that flanged end off, added about four inches of straight pipe, and it fit perfectly after that.

Sort of amazed at how eerily quiet she is now!

timmy0tool

iTrader: (7)

glad you got it taken care of. quiet is good for a luxury car!