Thoughts on when to replace O2 sensors...

[Lupo]

Just wanted to see everyone's thought on when to replace 02 sensors, whether there is a recommended mileage, or only when your ECU is throwing codes? And of course when the sensor is damaged becase you were an idiot..but that's another story.
Also, I wonder if anyone has ever replaced them and gotten some extra MPG for their trouble.

 

[Ishodu]

Its usually 60,000 miles or when you have issues with them is when you replace them. You may get a little extra fuel mileage if they are older.

 

[shojuan]

Over time I believe the O2 sensors start to switch more and more slowly. So although they still technically "work" they aren't working optimally...sort of like an old stretched out timing belt. I think 60,000 miles would probably be a good interval to change them unless funds are tight. I think a lot of newer cars tend to throw a check engine light (and a "time to change the O2 sensors" code) every 90,000 miles. Some of those cars even require a tricky little doohickie to plug in to reset the computer and idiot light. BMW's come to mind.

If your car runs rich I would think a more frequent change interval might be good. 60k or less. A lean running car might be more like 60-90k or more.

Lead poisons these things, just like catalytic converters. Also, regular silicones do too. The Si tend to cook off and form a coating of glass. And I'm just talking about vapors from silicone adhesives/gasket makers. It doesn't have to be chunks breaking off, it can be vapors. Good idea to use oxygen safe RTV in any part of the intake path. That includes valve cover and oil pan gaskets since the fumes inside the engine get scavenged by the PCV.

 

[SonicRiot]

Most quality O2 sensors will last 80K miles or more. They are designed to last longer than 60K, certainly. Nonetheless, they become lazy with time and contamination. You will have DECREASED fuel economy in most scenarios and the vehicle will not perform to it's potential at part throttle. Remember, at WOT the 02s aren't relevant, but the O2 sensors play a large role in normal, day-to-day driving at part throttle.

O2 sensors are not considered preventative maintenence. Many lazy O2 sensors will not throw a code, but a driver might notice decreased fuel economy or lack of part throttle performance. The long term fuel trims may be skewed in one direction or another, which will throw a light in OBDII vehicles, but not neccessarily in OBDI vehicles.

Test the resistance (ohms) and/or voltage at 60K miles and then every 10k afterwards. Replace them at 120K miles if it hasn't been done yet. O2 sensors are generally replaced when cats are replaced, as they were originally designed to last as long. I think federal mandates require 80-100K miles out of most emmissions related controls and sensors from manufacturers.

I work in a dealership and we have schedualed maintanences through 120K miles and 2, 5, and 10 year additional maintanences. No where does it say replace or even check O2 sensors. It is done on a case-by-case scenario. We find most owners will notice decreases in performance and fuel economy quickly if it begins to be an issue and the car will thusly end up in our shop.

Just some info.

 

[wood_e]

Also, the only brand to get is Bosch for the SHO

 

[SonicRiot]

I don't know if they were made by Bosch, but I would go with manufacturer original for O2 sensors... Motorcraft.

 

[Mr Anonymous]

Also, the only brand to get is Bosch for the SHO

Baloney. (Respectfully!)

As an emissions control component subject to all sorts of federal regulation, they are all very similar in performance and reliability.

In fact, I find the NTK sensors (oddly, Ford OE) generally last the longest, and switch the fastest.

I'd be willing to bet that within the next few years, federal emissions requirements are going to include switching performance minimums.

As mentioned, O2 sensors are pretty easy to test. A quality scan tool can monitor the switching and it's really pretty easy to pinpoint one that has become slow in switching.

 

[SHOtimer]

In fact, I find the NTK sensors (oddly, Ford OE) generally last the longest, and switch the fastest.

I have never seen those available. Where do you get those, or are they the Motorcraft ones?

Doug

 

[wood_e]

I hate feeling like I give bad advice... so I will say, after having borg warner O2s fail within 12,000 miles, the Bosch sensors I replaced those with were cheaper, and... work. Therefore, from my expirence I'll stay with what has worked for me.

 

[jedhead]

I changed my sensors at 125K because I was having problems passing emissions. The Bosch sensors I used didn't make any difference in the MPG or emissions. I just pulled the spout connector then my NOX plunged and I passed.

Bob

 

[NotSoSlowSHO]

In fact, I find the NTK sensors (oddly, Ford OE) generally last the longest, and switch the fastest.

Funny, I could have sworn I have pulled original O2 sensors on multiple Fords only to find that they were stamped with both "FORD" and "BOSCH".

 

[ManySHOs]

IIRC, NTK made the ATX HEGO sensors and Bosch made the MTX HEGO's.

I replaced my MTX HEGO's with Bosch units that I bought at NAPA.

When I had an ATX, I think that I bought new O2's from Ford (NTK IIRC).

Ian

 

[Ishodu]

My MTX had stock NGK or NTK ones in it for the record.

 

[Rockledge]

I used Bosch replacements on my SHO and my 4.0L OHV Ranger and they have worked great. Looked exactly liked the originals.

However, I tried two different replacement Bosch sensors from two different parts stores on my '97 3.0L Taurus GL and they both threw codes. Even though I tripled checked the part #s, the Bosch sensors wouldn't work right, and in fact, they didn't even look like the originasl that came off the GL. So I went to Ford and got the replacement 02 sensor from them - it was an NTK unit and looks exactly like the old one, and has worked great now for over a year.

 

[Jason Bowles]

I recently replaced my O2's and it was a motorcraft part not BOSCH. I dont know the difference between NTK and NGK but I put them on my 93 ATX and I went from 16mpg highway to over 26mpg highway. It's amazing what happens when you spend a little time loving your car.

Jason

 

[NotSoSlowSHO]

Hot damn Ive got a good memory.

And as it seems..... a crazy big collection of used and useless parts still in the garage

BOSCH:

 

[Mr Anonymous]

Someone needs a manicure!

Ford has been using NTK (which is part of NGK) for all their O2's since sometime in the early 90's. You can get them at some parts stores, but it can take some calling around to find them. With our Ford discount they are cheaper direct from them than the Bosch's or any others would be, so that's what we go with.

 

[Lupo]

I bit the bullet and got 2 new 02 sensors. The old ones were both Bosch with the long plug (OEM has short plug) and they were 2 different types. Slightly different from each other, with different numbers.
Would there be any need to to reset the ECU, or just replace them and go?

 

[SolidState]

my ATX ones were from Ford (SHOnut, actually) and say bosch on them. When I pulled the relatively new HEGOs out of my old 91, they were Ford NTK.

FWIW, my ATX HEGOs are less than 20k old, and one is toast. Slow to switch, throwing a lean code...

 

[NotSoSlowSHO]

Someone needs a manicure!

Ford has been using NTK (which is part of NGK) for all their O2's since sometime in the early 90's. You can get them at some parts stores, but it can take some calling around to find them. With our Ford discount they are cheaper direct from them than the Bosch's or any others would be, so that's what we go with.

I really dont care where to get them, or how much they cost.

All I was pointing out was that some Fords came from the factory with BOSCH 02 sensor. I have pulled factory installed 02 sensors made by Bosch from my '89 SHO, my brother's '93 Explorer, and my parents' '89 E-series Van.

And the camera makes my hands look worse than they are But hey, I WORK for a living, and play mechanic on the weekends.

Besides, lots of ladies like the "rough" hands