I'm the original owner of a well maintained 04 LS with 92K miles and nearly all the service has been at the dealer. Last visit they mentioned that the Y-pipe was bad based on the sound of things and they told me to go to an independent exhaust shop for repair to cut out a bad piece since they knew their price would be outrageous. After taking it for my first A/C check and recharge to an independent, they were looking for other things to do so I said they could possibly do the exhaust repair. They came back saying the Y pipe was riddled with pin holes and they suggested replacing it with a Bosal unit for $875 +/- $350 if the O2 sensors could not be reused. I see others here have used the Davico unit which costs a bit less. It sounded like most of those threads had people doing this job to repair error codes and yet I have had none and the car just passed emissions inspection last week. The dealer led me to believe that not repairing this would cause me more costs with a catalytic converter but it looks like most of these Y pipe assemblies include that. Was hoping to hear a consensus as to whether to just wait on this repair until I throw a code or spend the money now just to quiet the exhaust a bit. I don't know if an independent exhaust shop would be more aggressive replacing pipes since obviously enough is working if my OBD says so.

 

Bosal is very good and they make a lot of OE parts for many brands

 

Any images of the aftermarket exhaust?

The OEM is stainless steel and employs heat /noise(?) shields (damping inserts?)

The heat shields aid heat retention, thereby improving exhaust scavenging.

There appears to be a cross-over tube in the rear section of Y-pipe (?).

The area where stainless spring clamps clamp the heat shields are prone to corrosion.

LS430 configuration is well laid out and more efficient than LS400's.

Surprised you are experiencing leaks at such low mileage.

 

I took mine to a local independent exhaust specialist and he made a new Y-pipe from scratch using the original secondary CAT for just 150UKPounds.
It sounds and runs exactly like OEM.

You can buy aftermarket Y-pipes and have those fitted from cheap $200 ones to $$$ ones from Magnaflow and others.

 

Ive been running over a year now on the Davico one, no complaints

 

Thanks for the comments. I went to a shop that primarily does exhaust work and they cut out the Y pipe and fabricated a new one installed for $120. If this ever fails while I still own the car, I'll replace the whole unit then.

 

Very few (exhaust) shops can fabricate and...even fewer have equipment capable of welding stainless steel.

If your shop used stainless steel and competently fabricated and welded it, you are fortunate then.

A lot of hacks out there.

 

Its not that hard? I mean you don't really need much more than a mandrel bender and welder to do it.....and knowledge how to use both tools.

 

The combination of knowledge, equipment, and honesty have been in short supply for decades.

 

100% true unfortunately, It took me 2 years to find someone to make an exhaust and in the end It cost me $1500 and change for it. $550 for labor, $500 for mandrel bent piping, $380 for mufflers, $115 for a x pipe. Also a lot of so called "shops" are lazy and dishonest and they would rather use mild steel crush bent and charge the same as a stainless one.