I found out this weekend that the exhaust on my 98 OBW (2.5 DOHC) is leaking right behind the resonator. When I look at the schematic from Subaru, this piece of pipe with a resonator is labeled #12 in the schematic as rear exhaust pipe, but called centerpipe by most I have talked to sofar. According to the schematic it should bolt right behind the cat and so replacing it should be easy.

 

When I look under my car, it seems that there is a 3rd cat with a (2nd) oxygen sensor in it. And worse yet, it seems that this cat is welded to a short piece of pipe that is welded to the resonator. Immediately in front of the 3rd cat are the "spring-loaded" bolts with a flange that connect to the flange behind the second cat. This whole setup looks identical to that described in a previous post:

http://www.ultimatesubaru.org/forum/showthread.php?t=16317&highlight=cat%2A

Can anybody explain to me why this is, and how I get this fixed without spending hundreds of $$ on a piece of pipe with a 3rd cat in it (how many of these do you need?). As far as I can tell the whole thing is original and it is NOT a CA car but a regular mid-west model. The existence of the 3rd cat was confirmed by the Midas guy I asked about it.

exhaust.pdf

To get it fixed with out spending hundreds of dolllars you need to take it to an exhuast shop and just have them weld the holes shut. You wont need a whole new pipe or resinator. I'm sure the leaks are minor and can be welded shut. This will be WAY WAY cheaper than replacing pipes and resinators and cat converters.