Replace oxygen sensors?

[gapost]

I am working on my 2019 Tahoe with 122k miles. I have my exhaust pipe out and all four oxygen sensors are staring at me lol. Should I pro-actively replace them? I don’t have any codes but it would be pretty easy now.

 

[Doubeleive]

I am working on my 2019 Tahoe with 122k miles. I have my exhaust pipe out and all four oxygen sensors are staring at me lol. Should I pro-actively replace them? I don’t have any codes but it would be pretty easy now.

100k is there rated lifetime, typically they should all 4 be replaced at the same time.
so YES.
even though they could last who knows how long, it's not a bad idea

 

[OR VietVet]

Make sure you use either Genuine GM sensors. They are all listed at RA.

 

[Marky Dissod]

Not entirely sure that the REAR O2 sensors need replacing as often as the fronts.
If the engine's been working properly the whole time (unlikely?) the rears only see lean post-cat gases, unlike the fronts which see alternating lean / rich mixtures and work harder.

 

[OR VietVet]

IMO, if you have the easy access and are gonna keep the vehicle, change them all. It's only money. If you are going to change them, spray some penetrant on them now and let soak.

 

[Marky Dissod]

IMO, if you have the easy access and are gonna keep the vehicle, change them all. It's only money.

I don't disagree per se - just suggesting options based on the likelihood that the rear O2s may not need changing nearly as urgently as the fronts.

 

[gapost]

Thank you all. I will replace all four.

 

[Doubeleive]

I don't disagree per se - just suggesting options based on the likelihood that the rear O2s may not need changing nearly as urgently as the fronts.

it's just a preventitive measure, if you want to maintain your vehicle and not get slammed with all kinds of needed maintenance later when you may not be prepared to fork it out.
the 02 sensor may last much longer but it's like playing poker
As a rule, the service life of oxygen sensors in most 1996 and newer vehicles with OBD II should be 100,000 to 150,000 miles or more — assuming no problems that could cause the O2 sensors to fail prematurely
gm guidlines state a 100k service interval for 02 sensor's and that all 4 should be replaced at the same time.
I personally in the past have had a host of issue's with emmisions related problems, I have found maintaining the vehicle as recomended or even being more proactive has been effective in reducing these issue's.
things like the MAF for instance have no guidlines but I have found thru my own experience and reported experiences of others that 160k is the typical breaking point and that sensor alone can cause a laundry list of problems making you chase your tail like a cat.
with that being said a few things start to fail at 160k if you can be ahead of the game at that point in a vehicles useful life it can go by smoother.
It's also why market wide you see a lot of vehicles sold off at 160k because that is the breaking point when people do not maintain it and then all of a sudden it needs this and that and the other and the bill is just more than people want to spend on a "old car" which is counterintutive thinking but that's how it goes

 

[Marky Dissod]

I GENERALLY stipulate to what you just said ...
except just not SPECIFICALLY about FRONT O2 sensors vs REAR O2 sensors.

Front O2 sensors spend most of their lives never quite finding the exact middle ground of 0.35 - 0.5 Volts.
(I have seen the Fast O2 Rich / Lean Threshold Vs. CL Mode tables of over fifty vehicles; it's not simply 0.45Volts.)

Rear O2 sensors spend most of their lives under 0.4Volts. Over that, the catalytic converter is going bad.

Closest analogy I can think of:
Front brakes vs rear brakes seldom wear at the same rates.
That's all I'm getting at. Not saying it's a bad idea to replace all four.
Just saying replacing the fronts (alone) is a viable OPTION.