: getting the O2 sensor changed



redseville
09-16-05, 11:20 PM
what have all of you guys used to change that upper O2 sensor on the firewall side cylinder bank, I can see it, not sure what tool to use to remove it and change it out, its bad right now, this is in a 1997 seville. Thanks Mike

mcowden
09-17-05, 01:15 AM
what have all of you guys used to change that upper O2 sensor on the firewall side cylinder bank, I can see it, not sure what tool to use to remove it and change it out, its bad right now, this is in a 1997 seville. Thanks Mike

Hi Mike -

I was able to get it changed out using a very long 1/4" extension and the O2 sensor socket. Once it's broken loose, you should be able to twist it out with the harness. Getting the new one in there wasn't quite as easy, but I did get it by threading it in there CAREFULLY using the socket and extension again. It wasn't in a good position to turn by hand, and I didn't want to go twisting the harness on the new sensor.

That said, you may also be able to get at it from underneath the car using a 7/8" open end wrench, but I haven't tried that way.

Are you absolutely sure it's bad? What code are you getting? That is the bank 1 sensor 1 position, just for your reference. The one on the front manifold is bank 2 sensor 1, the one just before the catalytic converter is bank 1 sensor 2, and the one after the cat is bank 1 sensor 3.

redseville
09-17-05, 08:33 AM
I am getting the bank 1 sensor 1 code, no other codes, I checked the harness connection, after reading some past posts I will check the fuses in the engine bay before changing it.

mcowden
09-17-05, 06:26 PM
I am getting the bank 1 sensor 1 code, no other codes, I checked the harness connection, after reading some past posts I will check the fuses in the engine bay before changing it.

The fuses aren't going to give you an oxygen sensor code. If you've got the code, the sensor is not performing as it should. You can remove it and perhaps shake things loose a little bit or blow it out with some compressed air to try and breathe a little more life into it. They say not to use any solvents, but I have a feeling there are solvents that would be safe to use and others that are not. Hopefully someone will chime in here with some useful information in this regard.

What solvents are safe with the O2 sensor element and the stuff that accumulates on it?

Or, if you'd rather just get it done and not worry about it for quite a while, just replace it with a new one. New ones for your car are AC-Delco AFS-125 at about $52-$60 each or Bosch 13-474 at about $68-$75 each. I'd go for the Delco, personally.

94CaddyConcours
09-19-05, 03:27 PM
Who Many Sensor Does The Northstar Have And Where Is The Location?:d

mcowden
09-19-05, 04:06 PM
Who Many Sensor Does The Northstar Have And Where Is The Location?:d

There are 4 oxygen sensors. One in the front exhaust manifold, one in the rear exhaust manifold, one just in front of the catalytic converter, and one behind it. The two before and after the catalytic converter use one model sensor, and the other two use a different model. They are all heated oxygen sensors. Failure of any of them can result in reduced power and gas mileage and other negative symptoms that depend on the condition of lots of other factors. When they get crudded up or just go bad, only the bad sensor needs to be cleaned or replaced. You do not need to replace all 4 sensors when one stops working properly.

Replacement sensors vary in price from about $50 to about $75 each and it is generally best to stick with "OEM-style" sensors rather than Universal ones because the Universals require you to splice the wire harness, and that's just asking for trouble. Removal and replacement can be done with a few basic tools that include a special oxygen sensor socket or 7/8" crow's foot socket and possibly a long 3/8" extension, depending on the model and year of car.

When one or more of the sensors is not performing adequately, you will probably see a "SERVICE EMISSIONS SYSTEM" message on the dash and the Service Engine Soon light will illuminate. If you search the forums, you will find many good descriptions of the procedure to read the diagnostic codes. The codes will tell you exactly which sensor is misbehaving and what it's doing wrong. If your car has any DTC codes stored, look them up at the following web site for '96 or newer cars:

http://myweb.accessus.net/~090/dtcobd2.html

Or at this site for '95 or older cars:

http://myweb.accessus.net/~090/dtcobd1.html

Let us know if you need any help. Good luck.

Ranger
09-19-05, 05:35 PM
I do not know what solvents are O2 sensor safe but I do recall "Rob" saying that silicone is certain death.

mcowden
09-19-05, 06:19 PM
I do not know what solvents are O2 sensor safe but I do recall "Rob" saying that silicone is certain death.

So are you trying to tell me that I shouldn't let Pamela Anderson drive my car any more? :alchi:

Ranger
09-19-05, 06:51 PM
Nah, by all means, if you have the oppertunity, GO FOR IT. Just do not let her lean over the the fender to inspect the Northstar.