Cat converter: OE necessary? (2011 Impreza wagon)

[pianobrooks]

Hi all, I usually post about my '91 Loyale in the other forum, but I'm helping a friend consider exhaust repair options for her 2011 Impreza wagon. Her mechanic (who I often use myself and generally trust) tells me that for the cat converter (middle one, between the front cat and the resonator), they would only be willing to install a Subaru OE converter if they did the work. They said they have had problems with all of the aftermarket cat converters, for example issues with the CEL being triggered by the O2 sensor. It's not typical of this mechanic to insist on OE, so I think they might be onto something. But I wanted to check what the experiences of people on this forum has been.

 

Note: we're in upstate NY where there is plenty of salt corrosion on vehicles.

 

Thanks for your help!

 

- Brooks

[Numbchux]

We've tried aftermarket ones with a pretty poor success rate. Most are back within 6 months or so with a P0420.

[sirtokesalot]

nevermind ignore this

Edited January 5, 2017 by sirtokesalot

[golucky66]

Agreed with Numbchux, most if not all aftermarket cats suck. They woo you in with low prices compared to the OE but they don't last anywhere near as long.

[1 Lucky Texan]

hope they did good diagnosis if they are fighting P0420 - it can be a s simple as an exhaust leak. many times it isn't the cat.

[DaveT]

Double check for leaks. Even a small hole cracked gasket will throw it off.

[brus brother]

isn't there a federal warranty of some sort on exhaust/emissions parts beyond the 5 year 60K mile warranty??

there may be a recall?

check with SOA

Edited January 5, 2017 by brus brother

[1 Lucky Texan]

isn't there a federal warranty of some sort on exhaust/emissions parts beyond the 5 year 60K mile warranty??

there may be a recall?

check with SOA

 curiously, that extended emissions warranty varies by State - worth checking into, but it didn't help me with secondary air cut valves on my WRX in TX. Would have though in CA.

 

go figure

[brus brother]

 curiously, that extended emissions warranty varies by State - worth checking into, but it didn't help me with secondary air cut valves on my WRX in TX. Would have though in CA.

 

go figure

worth a vacation/drive to California? hang out at the beach until repaired then head on home ;-)

[pianobrooks]

Thanks all, the converter itself isn't bad - think in the context of ongoing underbody corrosion resulting from road salt. The flanges at the connection points have rusted apart for the 2nd cat, the resonator, and the muffler. Standard stuff in central NY state. It's taken me a while to get used to this after moving here. I was in Seattle before and you could use the same cat forever... here it is a different story. Kind of a waste of the platinum and other precious metals in the catalyst! But as far as I can tell, there is no alternative approach.

 

Probably should wash the underbody of our cars more often though, esp during winter, haha.

 

Thanks for the responses, I'm glad to know the OE cat is worth the expense.

[keith3267]

You should be able to use any cat that is CARB compliant.  In New York state, a CARB compliant cat is required.  It is one of seven states that have adopted the California emissions rules rather than writing their own.  But for many models, the only CARB compliant cats are the OEM.

[idosubaru]

There is one alternative -the flanges are usually what rots first and the rest is fine - cut them out and weld in new pipe.  Try an exhaust shop or mechanic willing to do exhaust repairs rather than replacements. 

A local shop charges $45 for the standard flange rust replacement and adds a little more if it's a bigger job.

 

If you weld in a piece of pipe to replace the flange, you no longer have a removable flange...but honestly they're never removable in the rust belt anyway after a short period of time. 

 

I think it's said that heat and the chemicals expedite the corrosion process, seems chemically astute. So if you're in a heated garage/conditioned space - wash underneath more often, and do more rinses in the spring to make sure chemical saturated surfaces aren't baking in spring/summer heat.

[DaveT]

If you have them weld on stainless flanges, and use stainless nuts & bolts, they come right apart.

[keith3267]

If you have them weld on stainless flanges, and use stainless nuts & bolts, they come right apart.

If you use SS nuts and bolts, you have to use an anti-seize or the threads will gall.  Copper anti-seize is recommended for this.  You can use SS nuts with high grade bolts or SS bolts with a cadmium plated nut without anti-seize.  SS bolt and plated nut is the best combo.

[DaveT]

Yeah I put anti seize on them also.