smlippa13

2006 LS430 needs new Y-Pipe due to crack at the "Y" that local muffler shop says can't be repaired and Lexus wants $1400 to replace. 2 clamps + 6 bolts hold the heat shield onto the Y-Pipe, bolts are badly rusted and will need to be replaced to re-install heat shield. Clamps look re-usable.
Does anyone know what the bolts are for this? Or will any bolts that fit the holes work?

Thank you.

StanVanDam

My recommendation is to buy an aftermarket Y-pipe instead of OEM, and to not reattach the heat shields - don't bother with the clamps and bolts. The dealership will not install an aftermarket Y-pipe, so you will need to find an exhaust shop near you to do the work.

The heat shields accelerate the rusting of the Y-pipe due to dissimilar metals (galvanic corrosion) and due to salt water getting between the shields and the Y-pipe, which burns off and leaves salt in direct contact with the pipe. I'm surprised your clamps are in good condition - your roads must not be salted in the winter, or you don't do much winter driving, or you wash the underside religiously?

Some aftermarkets Y-pipes are:
BOSAL 0961679 $218 USD @ RockAuto
DAVICO 58410 $185 USD @ RockAuto
DAVICO 137142 (emissions-certified) $287 USD @ eBay https://www.ebay.com/itm/01-06-LS430...-/190987141281

However, insist that your repair shop use OEM and not aftermarket gaskets when installing the Y-pipe. This work is only 1 hour of labor, so you should be able to drive away with a new Y-pipe for ~$300 USD. You really don't need to pay the dealer $1400 for this work, and by not reinstalling the heat shields, the usual LS430 Y-pipe corrosion issues will be prevented or at least significantly delayed.

warminwisc

Can the Y pipe be welded? Though I have seen this problem pop up it seems to be more of an uncommon problem as I live in Wisconsin drive alot of salty winter miles and have logged 150 k miles on each of m 04's. Thanks for your thorough reply Stan!

StanVanDam

I would remove the heat shields on the Y-pipe immediately. I believe if my car never had those heat shields, my original Y-pipe would never have cracked exactly at the front edge of the heat shield, where the salt water would first enter and burn off.

It is always good to question why the Lexus engineers wanted these heat shields on the Y-pipe. There are 3 likely purposes:
1) maintain constant exhaust gas temperature in order for the gases to evacuate as originally designed (intake and exhaust pressure waves, reflection points, flow resistance), based on OEM pipe diameters, OEM catalyst restrictions, OEM muffler restrictions, required backpressure, and many other variables involved in any proper exhaust system engineering design (e.g. using proper computational fluid dynamics analysis, as opposed to backyard hobbyists blindly assuming bigger and straighter pipes result in a more efficient exhaust flow). A cooldown in the exhaust in one section would definitely change the exhaust gas wave dynamics.
2) help the catalysts heat up faster to their max operating efficiency temperature
3) prevent you from starting grass fires when driving over dry brush.

I would sacrifice slightly changing the exhaust wave dynamics and having slower cat warmup time for a longer Y-pipe life. I rarely go offroading and don't often park on dry brush, so I'm not concerned about the fire hazard.

Several LS430 owners have reported on this forum and other forums that they were able to weld or patch their Y-pipe. However, it really depends on the severity of the damage and how early you catch the problem. In my situation, and I only got the opinion of one shop, they recommended against welding it because they weren't sure if their weld-job would hold up. If you have a crack, you could first try a tube of JB Weld High Heat Epoxy and DIY your own patch job at little to no risk, cost, or effort.

warminwisc

Thanks again! As usual you r 1 of the most insightful members of this forum

2KHarrier

My plan is to remove the heat shield and weld the crack. My 2001 has been giving me trouble since last fall, when I started getting a code for the B2S2 not reading correctly (P0430), You can hear a slight exhaust noise if you lay on the ground, next to the car. If I can't weld it, then I guess I have to fork out the 250 bucks or so for a new Y pipe.

To answer the OP's question, I would purchase stainless hardware from any hardware store. Take a couple of the originals with you and match up the diameter.

Perhaps someone will chime in with an approximate diameter.