Replacing front O2 sensors

[wmwtn]

Today I bought new front O2 sensors for my '98 GMC K1500 Suburban and I've never changed sensors before, so is there anything special I need to know before hand?

 

I'm thinking that the exhaust should be warm (not very hot or very cold) and some penetrating oil allowed to soak into the threads for a few minutes and then (hopefully) they will come out?? This vehicle has 128K miles with original sensors.

 

Any and all tips from those who have done this job greatly appreciated.

 

Many thanks,

Marty

[C & A s Dad]

I have only done this on a Dodge before and I had to have a special O2 sensor socket to remove it. The skt has a long slot down one side allowing the wire to pass through. You may can get to it with an open end wrench but be careful and make sure the open end wrench does not slip, rounding the corners.

 

The skts are not too expensive.

[Bish]

This is what I did. Warm exhaust and I coated the o2's with PB Blaster several times over an hour. I let it sit overnight. I used a regular open end wrench. You need to work it out and in and out and in like you are tapping threads. What happens is the rust gets caught in the threads and starts to bind so I thread it back in a turn then out a couple turns then in a turn, etc. Be patient and they will come out fine. Rush it or force it and you could ruin the threads in the bung and then your $70 o2 sensor costs you a new Y-pipe.

 

I replaced mine at 80K with Bosch and they are still going strong at 183K. The originals were not setting codes but they were lazy and my mileage dropped 2mpg.

 

Good Luck.

[wmwtn]

I looked at them last weekend and they looked like a standard hex type flange that could be removed with an adjustable or big open end wrench, but I'm sure not positive about that. I also talked with a fellow at work who has done it on a '93 GM truck and he said an adjustable wrench was what he used.

[wmwtn]

Thanks Bish, that's great info. I plan to do the work tomorrow or Sunday so I'll get some penetrating oil on them tonight and if I don't get to them tomorrow then I'll do some more penetrating oil tomorrow night. I changed from PB Blaster to Kroil a year or so ago so hopefully that'll be okay. Great info about working them out and in to clear the threads!! And as I'm working them in and out I'll add a little more penetrating oil to help matters. Many thanks, Marty.