Upstream O2 Sensors
Senior Member
Joined: Aug 2004
Posts: 583
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From: Michigan
If you have a 4x4, Plan on having them done. Otherwise you will need the specialty tool, a torch, and a lot of patience. I paid $180 for mine. 4 Hours later, some bloody knuckles and two trips to the hardware store... They were done.
Senior Member
Joined: Jul 1999
Posts: 2,233
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From: KC, MO
I have 61K on mine...what are you guys noticing after changing them besides a lighter wallet? No pre-cats in the way, so I'm thinking it'll be a pretty easy task...I just don't want to spend the $$$.
Senior Member
Joined: Jul 1999
Posts: 2,233
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From: KC, MO
Well, called my uncle in parts at a Ford stealership and the techs there think the whole 30K interval is BS. Well, I trust Mike T. over any factory tech, but they also said that if they have an emissions related code, the FIRST thing they do is pull any Bosch O2 sensor and put in a Motocraft before continuing any diagnostics. They said the Bosch O2 sensors are JUNK compared to Motorcraft. I stated that they are most likely one and the same, but they make a lot more off the facotry part and he said they have totally different elements. He also stated that Ford is not responsible for the O2 sensors as part of the 80K emisisons warranty...he said they are a maintenance item not covered after 3 / 36K. Can anyon shed any light on this before I drop the money on Bosch in favor of the uber-expensive Motocrafts? Also looking for more ammo to call back and own some techs. 
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Joined: Oct 2005
Posts: 300
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From: Lincoln, NE
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Joined: May 2005
Posts: 576
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From: Alabama
So now Bosch O2 sensors aren't good. First I find out that Fram filters(all of 'em) aren't any good, then I find out that Castrol isn't a good oil, then, Bosch plugs aren't any good, Duralast brake pads are crap. Jeez, it's a wonder any of my vehicles have made it to the 300K mark. And my truck with 420K? I guess I ought to start putting the parts you guys recommend in it. Maybe I could stretch it to the 500K mark. 
Seriously guys, sometimes ya'll make more of this stuff than it really is. Using good parts is essential, but doing the work right is sometimes even more.
Seriously guys, sometimes ya'll make more of this stuff than it really is. Using good parts is essential, but doing the work right is sometimes even more.
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Joined: Mar 1998
Posts: 13,385
Likes: 4
From: Virginia
Jackal,
This is one area where your techs don't know what we know - the Motorcraft units ARE in fact Bosch O2 sensors - Bosch makes those O2 sensors FOR FoMoCo. Next I'll bet they'll tel us all about how they have to replace those terrible Bosch brake systems with Motorcraft parts - which are also made by Bosch, by the way.
While a *proficient* line mechanic certainly will know some aspects about *repairing* vehicles we do not, since that is not what we do, I can tell you with certainty that we know more than the vast majority of average mechanics regarding how O2 sensors actually operate, their basic design, what they are made of, who makes them, when to replace them, how they wear, etc., because that falls into one of *our* areas of expertise - because we are tuners.
Just FYI, the upstream O2 sensor *is* in fact a 30K mile maintenance item - period. In fact, Bosh & virtually every other O2 sensor manufacture had that info on their web sites as well - until about 8-12 months ago, when 1 by 1, and due directly to pressure from the automakers, they changed those replacement intervals to 80K miles instead.
Would you like to know why?
Because 80K miles is the current (and soon to be lengthened) magic number for the separate EMISSIONS WARRANTY!! 80K miles - matches the current emissions warranty. See, the O2 sensor is an *emissions* part, and thus falls under a different and much longer warranty - the 80K mile emissions warranty. So if any automaker or O2 sensor manufacturer says to replace them before 80K, then the consumer has a bona fide case for making the automaker pay for it, because it's an emissions item. Its' also one reason why they have the practically worthless response-rate test, which we have seen virtually dead O2's pass time after time, because it's a meaningless standard.
So most of the O2 sensor manufacturers, who make their money from gigantic multi-million unit sales to the OEM's, sold out and reworded their replacement interval recommendation to - you guessed it - that magic 80K mile number.
It's up to each owner what they do with their vehicle, but I can tell you that I can tell if the O2 sensors are old just by looking at the datalogs that come in here, without me ever even seeing the vehicle. But then, I'm a tuner, and as such this is one of my areas of expertise that your average mechanic simply is not going to have, because they are not properly trained on this, because it's against the automaker's interests.
Just like a good mechanic knows all kinds of things about repairing vehicles that I will most likely *never* have - we each have our areas of expertise, and in this case, they do not overlap - that's all. It doesn't' mean they are "dumb," or bad people, etc - it's simply that they are not proficient like we are on that particular component.
I hold impromptu training sessions at our local Ford dealership almost every time I go there, telling their techs all kinds of things they know nothing about - and in turn, they share a lot of info with me - and the world turns round and round.
The bottom line is, anyone who runs their upstream O2 sensors for more than 30K miles in a supercharged engine, or 50K miles in a normally aspirated engine, is either ill-informed (which is usually the case, they just don't know because the automakers don't tell them), or just doesn't care about their vehicle enough to maintain it properly & isn't interested in getting proper performance, idle quality or fuel economy. Same goes for those who leave spark pugs in for more than 50K miles, and why there are no more grease fittings on suspensions anymore - that comes from the BS maintenance schedules the automakers out out in their attempts to show the lowest possible cost of ownership, so that fleet buyers (car rental companies, large construction contractors, the government, etc) will buy their vehicles.
The smart owner learns better.
This is one area where your techs don't know what we know - the Motorcraft units ARE in fact Bosch O2 sensors - Bosch makes those O2 sensors FOR FoMoCo. Next I'll bet they'll tel us all about how they have to replace those terrible Bosch brake systems with Motorcraft parts - which are also made by Bosch, by the way.
While a *proficient* line mechanic certainly will know some aspects about *repairing* vehicles we do not, since that is not what we do, I can tell you with certainty that we know more than the vast majority of average mechanics regarding how O2 sensors actually operate, their basic design, what they are made of, who makes them, when to replace them, how they wear, etc., because that falls into one of *our* areas of expertise - because we are tuners.
Just FYI, the upstream O2 sensor *is* in fact a 30K mile maintenance item - period. In fact, Bosh & virtually every other O2 sensor manufacture had that info on their web sites as well - until about 8-12 months ago, when 1 by 1, and due directly to pressure from the automakers, they changed those replacement intervals to 80K miles instead.
Would you like to know why?
Because 80K miles is the current (and soon to be lengthened) magic number for the separate EMISSIONS WARRANTY!! 80K miles - matches the current emissions warranty. See, the O2 sensor is an *emissions* part, and thus falls under a different and much longer warranty - the 80K mile emissions warranty. So if any automaker or O2 sensor manufacturer says to replace them before 80K, then the consumer has a bona fide case for making the automaker pay for it, because it's an emissions item. Its' also one reason why they have the practically worthless response-rate test, which we have seen virtually dead O2's pass time after time, because it's a meaningless standard.
So most of the O2 sensor manufacturers, who make their money from gigantic multi-million unit sales to the OEM's, sold out and reworded their replacement interval recommendation to - you guessed it - that magic 80K mile number.
It's up to each owner what they do with their vehicle, but I can tell you that I can tell if the O2 sensors are old just by looking at the datalogs that come in here, without me ever even seeing the vehicle. But then, I'm a tuner, and as such this is one of my areas of expertise that your average mechanic simply is not going to have, because they are not properly trained on this, because it's against the automaker's interests.
Just like a good mechanic knows all kinds of things about repairing vehicles that I will most likely *never* have - we each have our areas of expertise, and in this case, they do not overlap - that's all. It doesn't' mean they are "dumb," or bad people, etc - it's simply that they are not proficient like we are on that particular component.
I hold impromptu training sessions at our local Ford dealership almost every time I go there, telling their techs all kinds of things they know nothing about - and in turn, they share a lot of info with me - and the world turns round and round.
The bottom line is, anyone who runs their upstream O2 sensors for more than 30K miles in a supercharged engine, or 50K miles in a normally aspirated engine, is either ill-informed (which is usually the case, they just don't know because the automakers don't tell them), or just doesn't care about their vehicle enough to maintain it properly & isn't interested in getting proper performance, idle quality or fuel economy. Same goes for those who leave spark pugs in for more than 50K miles, and why there are no more grease fittings on suspensions anymore - that comes from the BS maintenance schedules the automakers out out in their attempts to show the lowest possible cost of ownership, so that fleet buyers (car rental companies, large construction contractors, the government, etc) will buy their vehicles.
The smart owner learns better.