Exhaust - Muffler replacement.

When I purchased my XB I found that the check engine light was on.  As a standard practice I take my snap on Ethos scan tool with me when looking at used cars.   I found that it had P0420 for a Catalyst below efficiency code.   The car has over 200k miles so I expected that the catalyst would be bad.

I purchased the catalyst, resonator and the muffler so as to be sure to replace everything in one swoop.   with this high of mileage I might as well do it now rather than piece by piece.   

The first item I replaced was the Muffler.  I purchased a Walker 54602 Quiet-Flow Stainless Steel Muffler Assembly from Amazon.com.  It was pretty quick delivery and only took a couple days.

It fit very well.  The rubber hanger are in the right location as the factory ones.   The assembly is the correct size and fit into the same spot without issues.   The coupling to the factory exhaust system was spot on.   I reused the old factory clamp and gasket for now because I will be replacing the complete exhaust system one my replacement oxygen sensor arrives.

Couples to the factory pipes without issues. 

Muffler fits into the factory location without issue

Exhaust hangers are in the right locations.

I noticed that the muffler tip does not reach to the back of the bumper opening.   So a muffler tip will be needed.  Otherwise the exhaust fumes will just gather under the bottom and swirl with the turbulence and possibly come back into the passenger compartment with the windows down I would think.

Muffler tip not long enough.

Be sure to use a lubricating oil on the rubber exhaust hangers to be able to slip them off the factory barbs.   It is pretty tough to get off without it.   The flare on the tips are pretty big.

I preparation for the exhaust replacement I sprayed Kroil on all the exhaust nuts and bolt to get the rust soft, then I broke the bolts loose and re-tightend them.   Now Im ready to go once everything is here.



Tools used to replace the muffler.  Lubricating oil, Pry bar. 12mm socket, 3/8 drive ratchet.

Parts used, Walker 54602 Quiet-Flow Stainless Steel Muffler Assembly

Exhaust - Catalytic converter and Resonator and A/F sensor upstream.

When I purchased my XB I took my scan tool to be able to check if there are any current or pending codes.

I found P0420 for low catalyst efficiency.   Usually when I see this it is because the Catalyst needs to be replaced.  This vehicle has 208,000 miles on it.  So the catalyst would be expected to be replaced.

I decided to do the work myself.   I went to Amazon.com and order a catalyst, resonator, muffler, Air/fuel sensor (the upstream one).   Clamps and gaskets to go with it.
Here is my overall approach to this job.

1. I put the front end on jack stands to give me clearance.  
2. I then disconnected the muffler clamp and muffler.  Leaving the muffler in the car. 
3. I then removed the metal cross bar under the body preventing the exhaust from coming off and the rubber hangers. 
4. I then removed the stock 14mm bolts holding the catalytic converter to the exhaust manifold. 
5. I then installed the Walker Catalytic converter.
6. I then installed the Walker Resonator and pipe clamp 35335
7. I then connected the Resonator to the Muffler with Gasket 31577 and clamp 36519

Here are all the parts laid out how they go.  Overall I think the Walker parts match up to the factory ones well.  The hanger bars are in the right location and the flanges seem to be correct.  I continued to install them.

Overview - Left to right, Catalyst, Resonator.

side by side with the factory exhaust one piece.

The two parts slip together and I used the clamp to seal them. 

Walker 31378 Exhaust Gasket

Factory gasket on the left, Walker on the right.

Removed factory exhaust clamp.

Separating the factory exhaust pipe.

Remove rear cross bar.

Lube up and removed exhaust from the rubber hangers

Removed Rear O2 sensor

Removed front O2 connector and catalyst bolts. 

I re-used the factory cat to manifold bolts.

Installed the Walker 53613 Ultra Import Converter and let hang.

Slipped the Walker 55467 Resonator Assembly into the catalyst and snugged down the clamp for the two pieces.

I put the clamp facing the drivers side to not interfere with the rear O2 sensor installation,  These are 14mm nuts.

Walker Exhaust 35335 Hrdwr-Clmp .

New Walker 31577 Exhaust Gasket .

Muffler Walker 36519 Exhaust Clamp

Walker clamp with 13mm nut and bolt.

Re-installed rear downstream sensor.

Upstream replacement sensor because the old one had gauld threads.  The Denso 234-4524 (Air and Fuel Ratio Sensor) comes with copper thread lube so I put some on the rear sensor before installing that one.  The Denso one comes pre-lube with black anti seize.   

Installed new Denso upstream sensor. Bolted right up and the connector was a match.  No issues on this one.

When all done and I started the car, I did notice the note was more quiet then before.  During driving to check for leaks and loose parts, I did notice the toned down sound.  I like that since my driving is more around town and I'm not a young kid trying to sound cool.  

Hope this was helpful.  If you have questions please let me know and I can add to this post.



Parts used. Walker 53613 Ultra Import Converter - Non-CARB Compliant , Walker 55467 Resonator Assembly , Walker Exhaust 35335 Hrdwr-Clmp , Walker 36519 Exhaust Clamp , Walker 54602 Quiet-Flow Stainless Steel Muffler , Walker 31577 Muffler Exhaust Gasket , Walker 31378 Exhaust Gasket Catalytic Converter , Denso 234-4524 (Air and Fuel Ratio Sensor)

Tools used - 1/2 inch drive ratchet, 1/2 drive 8 inch extension, 1/2 drive 14mm socket, 13mm box wrench, 14mm box wrench, adjustable wrench for oxygen sensors.



Time to complete the job - about 2 hours.



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