93 legacy oxy sensor replacement

[bgambino]

hey guys

I have a code 32 and want to replace my oxygens sensor...I took a quick peek and it looks tight down there,,

1--do i have to drop the Y pipe off the engine??

2--does it stick out enough to use a box wrench or do I have to buy a special socket?

 

please dont advise doing a seach on the subject...I did...spent 1/2 hour...was some nice reading but nothing that directly answered my question

 

3--one of the guys here gave me a nice link for reading the codes on these early legacies...http://www.surrealmirage.com/subaru/engine.html

Can anyone explain the difference in "erasing the trouble codes" and "resetting the ECU"? Which will I need to do after replacing the O sensor?

thanks

[GeneralDisorder]

Drop the y-pipe. You'll need to in order to get at it, and to chase the threads properly. These are hard enough as it is - near impossible if you don't take the y-pipe off the car to work on it.

 

These are almost always real tough to get out. A special socket is nice, but I've done many without one. I usually just cut the O2 off with a die grinder to fit a normal socket on it (then use an impact). Warm up the engine to operating temp and pull the exhaust off while it's still warm. This helps in getting them out.

 

Chase the threads with a spark plug thread chaser and use anti-seize on the new sensor.

 

GD

[edrach]

I suspect it's the same as my '91 Legacy and I don't remember having any trouble getting it with a box wrench. Drop some rust penetrant on it for a few days before you do remove it; it'll make the job easier. I would suggest Jason at Mike Scarf Subaru (www.1stsubaruparts.com); he has an 800 # and is only a UPS shipment away; OEM is best for an O2 sensor. Never-seeze works well too.

[GeneralDisorder]

Yeah - if you douse it in PB blaster or Yield or something for a few days that might help. I never seem to know in advance when I'm going to be doing stuff like this so I just strong-arm my way around it. If you can get a box-wrench on it by cutting the old wire try that first. I always seem to have to use an impact on them, and then chasing the threads is needed so you need better access to run the thread chasing tap in.

 

GD

[avk]

Recently I replaced one on a 1995, w/o dropping the Y. A socket that

did work was a "heavy duty" offset type with a double-square 1/2" drive.

You just need to put the socket and the breaker bar into the right position.

The converter housing is stainless, so the sensor should come out without much struggle,

especially after applying PB Blaster for a couple of days.

[GeneralDisorder]

The converter housing is stainless, so the sensor should come out without much struggle,

especially after applying PB Blaster for a couple of days.

 

It's not the rust, it's the carbon. I've had the sensors come out (with a BATTLE) and leave all their threads in the coverter. Basically it was such a battle because I wasn't so much unscrewing the sensor as ripping it's threads off. But I've been able to chase them out and get a new sensor to thread in alright.

 

GD

[avk]

I see. Could it be that there's more carbon in the exhaust on pre-OBDII vehicles?

With my sensor, the best I could tell it was the rusted sealing ring

which was making it hard to turn. It fell off afterwards. The converter threads

were in a good shape and I just wiped them with brake cleaner.

[GeneralDisorder]

I see. Could it be that there's more carbon in the exhaust on pre-OBDII vehicles?

 

No - it's purely a matter of how much oil is being burned. That's largely a factor of the age and condition of the engine. Has nothing to do with OBD or any other emissions control system. Burned oil doesn't show up as hydrocarbons so while it may eventually clog the cat, it doesn't cause the car to fail inspections. That's why they always look for "visible" exhaust as well as test results, or an ECU probe.

 

GD