Catalytic Converter Replacement

[wandersub]

I have an engine code on my 2001 Forester that's been coming up for a while telling me I have a catalytic converter (CC) problem. I plan to replace it but I have a couple quick questions.

 

1) How do I tell if I have California or Federal emission standard CC? Does it matter since I live in Texas?

 

2) I found a replacement part for the full front and rear CC assembly but it doesn't show any gaskets on either end. Is that right?

 

3) Should I replace the oxygen sensors as well? Front, Rear, Both?

 

4) Is there anything else I should be checking that may have caused my CC to go bad in the first place?

 

5) I read the manual I downloaded on line a long time ago and the repalcement looks pretty simple. Any gotchas I should be aware of?

 

Thanks for your help!

 

Alan

[idosubaru]

exhaust work is simple with two major annoyances. working on your back/under the car. and rusted/deteriorated bolts. spray them good with liquid wrench or PB blaster (WD40 is not a good alternative). best to wet them good a couple of times prior to working on it, particularly if they look bad. there should be gaskets at any exhaust flange or juncture but i am not familiar with foresters specifically. typically they have a doughnut gasket at the front of the converter assembly and a gasket at the rear.

 

in texas i doubt it would matter at all what you replace it with. i live in the north east, famous for rediculous emissions and auto laws. i replaced mine with an aftermarket converter ($35), welded it in place of my old (hollowed out) converter and all was fine, passed emissions easily. each state is different though, some (like VA) are immensley anal about exhaust work....but i can't imagine texas being like that. the state...that every time i drive through it i see multiple vehicles towing (well...pulling, towing is kind of generous!!) other vehicles on the interstate with a rope or chain.

 

i'm surprised your converter is bad, are you sure?

[nipper]

First thing first, check your 02 sensors. i would bet you have a a bad o2 sensor before a bad cat. a bad tank of gas ( a really really bad tank), or running too rich can cause a cat to go bad.

How many miles are on this car?

[cookie]

I got a PO 420 and was assured that it was my converters. One front oxegen sensor later for $60 and it has been cured for a long time. I vote with Nipper to try that first.

If your car is a CA model it will have a sticker saying so.

[nipper]

Even if it is both sensors, it is much cheaper to replace them both then the cats, and still get a bad cat code. The o2 sensors have a finite life, where as the cats seem to be lasting longer and longer (low sulfur fuels). When i replace a cat if everything is original and im doing it myslef, i'll replace the o2 sensors too. The exhauts system on cars have gotten much easier to work on, and soobies are almost a dream compared to what they used to be like. Bolted flanges are wonderful. There are gaskets at the cylinder head and at the flanges (i'm 90% sure about the flanges)

 

nipper

[Wayne Boncyk]

I COMPLETELY agree with Nipper. Change both the O2 sensors first, make sure that you use anti-seize on the threads, and if you still have the problem, only then would I resort to changing the cats (and you can re-use those O2 sensors that you just tried!!) Even then, the front cat does the bulk of the exhaust scrubbing on the Sube design so that's the one I'd start with if I were resigned to changing a cat.

 

It really doesn't make any difference if your car is Federal or California certified. Subaru, like many of the other Japanese manufacturers, figured out that the same components can be used to qual a car to either set of standards, so starting with the first OBD-II equipped cars in 1996 (actually late '95 for some models), they have built every unit with components that will pass California emissions -- they just reserve the more involved qual testing that California requires for those units that will be shipped there. Your parts are identical to a Cal approved car, regardless of what standard it has been qual'd to. To find out which standard was applied to your car originally, read the emissions sticker that should be stuck to the inside of your hood.

[wandersub]

Thanks all. The car has 160K miles on it and I have had the front O2 sensor replaced on recall twice before and I think for each of those I actually had an O2 sensor code show up, not just the cat. The problem always seems to come back. It's not just the cat code but also a lull during intial acceleration. I've been told that can be a sign of a bad cat as well. Any opinions on that.

 

Alan

[nipper]

Thanks all. The car has 160K miles on it and I have had the front O2 sensor replaced on recall twice before and I think for each of those I actually had an O2 sensor code show up, not just the cat. The problem always seems to come back. It's not just the cat code but also a lull during intial acceleration. I've been told that can be a sign of a bad cat as well. Any opinions on that.

 

Alan

 

promise me you wont laugh, but hit the cat with your hand or a rubber mallet. If you can hear it ratle inside it is shot. Also at that mileage it wouldnt be unheard of. a clogged cat would limit throttle response.

 

nipper