oxygen sensor replacement

[Niles Ferrier]

I have a 2001 Outback Wagon limited and I need to replace the o2
sensors. I bought the rear one first and I subscribed to
alldatadiy.com which has printable diagrams.

I was wondering 2 things. First, has anyone done this and perhaps
taken pictures? the diagrams arent that great. And second, any
advice?

Thanks

NF

 

[Rick Courtright]

And second, any advice?

Hi,

O2 sensors are often available as an OEM replacement (includes factory
connector) or a universal style (where you splice the wire.) Avoid the
universal style whenever possible--the length of the wire and integrity
of the connection are problematic in some apps. Hope the one you got is
the OEM style.

Dunno about your car, but the older Subies used the screw in style
sensor. It requires a spark plug type socket to remove easily. The
socket has a slot in the side to allow the wire to be pushed out of the
way. Auto parts stores have 'em--they're not that expensive.

The sensors sometimes get almost frozen in place. Warming the exhaust
sytem (doesn't have to be real hot) often helps you break the old sensor
loose.

When installing a new screw-in sensor, some anti-seize compound should
be used on the threads. Many sensors ship w/ the compound already
smeared on the threads. Make sure you DO use some a/s compound or you'll
REALLY get the frozen sensor blues next time you try to remove one.

Many people put a bit of dielectric grease on plug-in electrical
connections when they install new bits. Subaru even suggested it at one
time as they were having corrosion problems w/ some underhood
connectors. A caution, though: I used to subscibe to a newsletter that
had "topic of the month" kinds of info. In one, the author warned
against using any grease or other substance on O2 sensor connections.
The reason was the insulation on a lot of the wires is extruded w/ tiny
air vents lengthwise thru the plastic (for temperature control), and
foreign substances in the connectors can clog them. The cooling effect
is compromised, w/ attendant errors in reading the voltages by the ECU,
which might result in running problems.

Good luck!

Rick

 

[Carl 1 Lucky Texan]

I have a 2001 Outback Wagon limited and I need to replace the o2
sensors. I bought the rear one first and I subscribed to
alldatadiy.com which has printable diagrams.

I was wondering 2 things. First, has anyone done this and perhaps
taken pictures? the diagrams arent that great. And second, any
advice?

Thanks

NF

What code did you get. Did you try clearing the CEL and see what code ,
if any , came back? How many miles on the car. How do you know the rear
sensor is bad?

Carl

 

[Niles Ferrier]

What code did you get. Did you try clearing the CEL and see what code ,
if any , came back? How many miles on the car. How do you know the rear
sensor is bad?

Carl

the car has 137,000 miles on it. Dont know any codes, figured that it
was time to change the sensors. starting with the rear one because the
rear one is the cheaper of the 2.

I know, I should get a scan gauge.

 

[Uncle Ben]

the car has 137,000 miles on it. Dont know any codes, figured that it
was time to change the sensors. starting with the rear one because the
rear one is the cheaper of the 2.

I know, I should get a scan gauge.- Hide quoted text -

- Show quoted text -

You can get a scan code reader cheap ($50) from change2e85.com.

 

[Carl 1 Lucky Texan]

the car has 137,000 miles on it. Dont know any codes, figured that it
was time to change the sensors. starting with the rear one because the
rear one is the cheaper of the 2.

I know, I should get a scan gauge.

Usually, the front sensor will go bad before the rear. It is hotter and
exposed to somewhat more corrosive gasses I think. 137k is a lot of
miles for the original sebsors and changing them 'preventively' is not
stupid, but may not strcitly be required.
Is your CEL on? Often, parts suppliers like Autozone, carQuest and
others will scan the car at no/little charge. Even a friendly nechanic
might do so on a slow day for a coupla lotto tickets. If you get the
codes read, post them and someone here may be able to point you in the
right direction. Is the car running poorly/bad mileage?

Carl

 

[Niles Ferrier]

Usually, the front sensor will go bad before the rear. It is hotter and
exposed to somewhat more corrosive gasses I think. 137k is a lot of
miles for the original sebsors and changing them 'preventively' is not
stupid, but may not strcitly be required.
Is your CEL on? Often, parts suppliers like Autozone, carQuest and
others will scan the car at no/little charge. Even a friendly nechanic
might do so on a slow day for a coupla lotto tickets. If you get the
codes read, post them and someone here may be able to point you in the
right direction. Is the car running poorly/bad mileage?

Carl

CEL is on and has been on for some time now. I am changing for a
couple of reasons:
1. Why not? Not that expensive. 2. Gas prices. 3. Gas mileage is lower
than it was when we first got it (bought it new).

I do realize that mileage will go down as a car gets older, I do
recall getting either over 30 or closer to it. Right now I am getting
23mpg for mostly highway driving.

 

[Carl 1 Lucky Texan]

CEL is on and has been on for some time now. I am changing for a
couple of reasons:
1. Why not? Not that expensive. 2. Gas prices. 3. Gas mileage is lower
than it was when we first got it (bought it new).

I do realize that mileage will go down as a car gets older, I do
recall getting either over 30 or closer to it. Right now I am getting
23mpg for mostly highway driving.

There are quite a few sensors that could affect gas mileage. A NOTORIOUS
one is the Engine Temp Sensor (not the coolant gauge sender).

When were the plugs changed? Could the injectors be dirty? Is the cat.
converter. partially clogged? Is the MAF bad/intermittent?

whatever


Carl