I have to replace the front oxygen sensor on my Outback and I got under it to spray it to loosen it up and my question is how do you get a wrench on it?It is buried in the heat shield and above the Y pipe.What is the secret to getting it out of there?

They sell special sockets for the Sensor Removal, but I've always used a 7/8 tubing wrench. Sears has them.

I tried to reach it with a regular open end wrench but there's no way to get it in there.

https://www.automedicsupply.com/showpicture.php?&sensor=27110

 

There are a few different tools made specifically for this purpose; there are three of them that come in the kit above. You can buy them individually if you know which one will work for your situation.

I used a wrench like this, and put pipe on the end to get more torque. The special tool sucked.

 

I bought the wrench from sears or osh...same thing.

 

http://s7.sears.com/is/image/Sears/00944362000?wid=100&hei=100&op_sharpen=1

Just did my 99 front sensor yesterday, I had a special socket which isn't even close to being able to fit. I had a 22 mm box end combination wrench which I had sawed off in the middle in the past for another car. I guided the box end over the wire with the angle of the wrench head leaning toward the rear of the car. I already had the mass air sensor and air cleaner cover off to access the wire connector and the wire support so there was a lot of room to look down from above. The end of the wrench protruded up between the transmission and the fenderwell, and I lightly put a pair of vise grips on the sensor body so the wrench could not slip off the hex. I gave the wrench one light tap with a hammer and it broke loose with almost no effort. I did the rest of the threading out and the new one in from underneath, and the only other tricks were avoiding having the wire twist up while threading the new one in, and making sure the old washer came out with the old sensor (like a spark plug washer). The original sensor was a Bosch, and the replacement from Subaru was a Hitachi.

You can also gain access to the O2 sensor through the front right wheel well.

I have access to a hoist so getting under the car is no problem .The problem is getting a wrench in there.I'll try some of your suggestions.

Please let us know if it fixes the P1133 ECU code.

Please let us know if it fixes the P1133 ECU code.

 

I was changing it due to a 420 code.I changed it last night so we'll see now if it's fixed.Thanks for all your input.It went pretty smoothly.A mechanic friend had a sensor wrench for a ratchet and it worked great.

I have access to a hoist so getting under the car is no problem .The problem is getting a wrench in there.I'll try some of your suggestions.

 

If it's the same gear as my '02 OBW (and I think it is)...getting under the car **is** the problem. Pull the right front wheel, and you'll be able to reach in through the wheel well and get it with a normal open-end wrench, no problem.

 

The rear O2 sensor is a bit trickier to get a wrench on than the front -- might need that special socket for the rear.

 

If all else fails, access can be gained definitively by dropping the cat. Bolts on exhaust flanges can be extremely stubborn or worse though. And if you go this route, have new gaskets on hand for sure.

 

EDIT: Ok, negelected to read the part where you already got it out. Now back to your regularly scheduled programming...

this is the wrench that works for me on my '01 Forester

 

(see attachment)

this is the wrench that works for me on my '01 Forester

 

(see attachment)

 

That is the one I used.It worked out well.I just hope the CEL stays off now.

this is the wrench that works for me on my '01 Forester

 

(see attachment)

What is that wrench called and where does one get it? I need to change the front O2 sensor on my 2000 Impreza 4dr sedan (2.2L). I'm hoping that the suggestions I have read here will help me as well.

What is that wrench called and where does one get it? I need to change the front O2 sensor on my 2000 Impreza 4dr sedan (2.2L). I'm hoping that the suggestions I have read here will help me as well.

I can actually get a 22mmopen-end wrench on the O2 sensor on my 2000 Impreza. It lives in the front of the catalytic converter and doesn't look too hard to access.

What is that wrench called and where does one get it? I need to change the front O2 sensor on my 2000 Impreza 4dr sedan (2.2L). I'm hoping that the suggestions I have read here will help me as well.

 

its referred to as an "offset" sensor socket. I got mine off EBay for $15 about a year ago. do a google on "offset sensor socket" and you'll get all kinds of hits. If you can get to it with an open-end wrenceh - thats another way