Catalytic Converter Replacement Help.

Howdy,

 

In a few weeks I'm making time to replace my catalytic converters. This is my first time doing this job. I'm looking for some pointers:

 

A. What should I assess and determine prior to purchasing the new catalytic converters? ... What should I look for on the old system and where it is connected to the rest of the car in order to determine what I will need to do the job?

 

B. I need to replace both catalytic converters and would like to spend the least amount of money possible. I would like to keep my spending in the realm of $300.00. From my online research this seems a bit tricky.

 

C. What should I look out for while I am doing the job?

 

Any help that can be offered would be most appreciated.

 

Thank you.

I may to look into this too. I've got some ungodly rattling going on. I went to get new tires, and asked them to check it out and see if my exhaust cover was loose. They said it seems to be my Cat, so i guess i may be learning how to replace that soon...

I had this issue months back, my thread and sound clip: http://legacygt.com/forums/showthread.php/engine-rattle-216473.html?t=216473&highlight=engine+rattle

 

Mechanic thought it was the down pipe catts going out, it ended up being my up pipe gasket had separated and was causing the crazy rattle. Many idea's as to what it could be in this thread GL, I hate weird sounds. Generally the catalytic converters should last 100-120k plus+. How many miles on your car?

If it is the DP try and find a used one like this:http://legacygt.com/forums/showthread.php/fs-sofla-05-lgt-stock-exhaust-aftermarket-axel-backs-and-219897.html?t=219897&highlight=fs+oem+pipe hopefully low mileage.

Will do. I'm hoping it'll just be a shield issue.

Out of curiosity, what do you do with them?

Howdy,

 

In a few weeks I'm making time to replace my catalytic converters. This is my first time doing this job. I'm looking for some pointers:

 

A. What should I assess and determine prior to purchasing the new catalytic converters? ... What should I look for on the old system and where it is connected to the rest of the car in order to determine what I will need to do the job?

 

B. I need to replace both catalytic converters and would like to spend the least amount of money possible. I would like to keep my spending in the realm of $300.00. From my online research this seems a bit tricky.

 

C. What should I look out for while I am doing the job?

 

Any help that can be offered would be most appreciated.

 

Thank you.

 

If you car is a PZEV 2005 model you are somewhat screwed. If not go online to Amazon or ebay and search for a Walker replacement cat-section 00-07 Impreza, 00-05 Legacy, OB, Baja or Forest (NON TURBO) will fit.

If it's P0420 you're getting, I would look up the viability of the O2 Spacer mod. Works for all Subarus with EJ motors up to 2004 that I know of, not sure about the newer stuff. If it's plugged, then you're SOL and need to buy new ones. Stay away from Walker Cat's if you're running California emissions, as they clog up and rattle apart within a few thousand miles and P0420 will follow shortly after (experience tells me this, your results may vary). As stated above, OEM works best, but cost could be over $1000.

 

Steve

Thanks for all the replys.

 

I believe my converters to be bad because:

 

A. I had an OBD hooked up to it and the reading came back that both of my Cats needed replacing. (I am going to assume this to be the P0420 reading you are talking about)

 

B. A loud rattling occurs under my at the begginning of acceleration.

 

C. My cars MPG is not what it once was, I purchased some catalytic converter cleaner, used it and during one long drive with that in my gas tank my mileage improved briefly from about 24 mpg to about 28mpg.

 

D. I have about 112k on the car.

 

Make sense?

 

Thank you for all the suggestions on Cats. I will look into Walkers. It seems best price on OEM is about $200.

I would ask what code was pulled. A lot of shops who don't have experience with Subarus will just replace cats for a code P0420. Do some research and educate yourself and try to see if you can save some $$$. As for the rattle, verify it isn't a heat shield, as all Subarus of higher mileage have heat shield rattles. I have had two cars with P0420 and bad rattles, only one was a bad cat, but even still, the P0420 was defeated with the O2 sensor spacer mod in both instances.

 

Edit: Did a quick search http://forums.nasioc.com/forums/showthread.php?t=2234058 spacer will not work for your car. But still get the error code number and post it here.

I've got some Rhino Ramps i found on sale, so i'm going to try and get under my car later and see if i can find the rattle in the shields, or if i have to start looking into swapping out my cat. Is it something that would be very hard to do at home on an 09 n/a Legacy?

With the exception of the Y-pipe (which is attached to the head), All bolts will either come out or snap. They are just nuts and bolts. If you break any, grade 5 should be a suitable replacement, but I have always run grade 8. You can find either at a hardware store, or tractor supply. If you have spring bolts on the mid pipe, reuse the springs, and make sure to get the gaskets for the pipes. As for the Y-Pipe, if you are going to replace those Cats, I would use a set of torches to heat and remove the head to Y-Pipe bolts. If you don't have access/know how to use torches, try PB Blaster. Work the bolts in and out to get them out, and if they feel like they are going to snap, stop and have a shop get them out. Drilling out heads suck, and can cause damage if not done right (ask me how I know).

 

Hope that helps,

 

Steve