Is there a general replacement time for O2 Sensors. I have a Mercury Villager with 130K Km. It runs good, starts will and gets about the same milage as when new. Should the O2 Sensor need replacing?
O2 Sensor, when to replace it?
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Patman
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If your car is running well and gas mileage hasn't taken a big dive, then leave it alone until it does.
One of my 02 sensors crapped out on me last year, at right around 120,000km I believe, and I ended up just replacing both of them at the same time. I ended up getting a check engine light and very poor performance all of a sudden, and luckily it happened at one of my car club's dragstrip outings, so someone there hooked up his scan tool software and saw the code which showed one of the sensors was causing one side to run far too lean.
One of my 02 sensors crapped out on me last year, at right around 120,000km I believe, and I ended up just replacing both of them at the same time. I ended up getting a check engine light and very poor performance all of a sudden, and luckily it happened at one of my car club's dragstrip outings, so someone there hooked up his scan tool software and saw the code which showed one of the sensors was causing one side to run far too lean.
Look in a service manual.
I think that most of them go around 60-80K+
My manual says 80K replace good or not.
My original lasted about there, and I talked to the dealer and they told me for my truck they would replace at 80K.
Well I have 87K on that o2, and for the last 5-6 tanks of gas my milage has suffered (after replacing a CAT)... maybe it's on the way out...
If so, I'll just plan on replacing at 80K or slightly less. I have had other cars last much longer (over 160K) but not my Tacoma.
So I think it's user and CAR specific... Check the service manual.
I don't think there is a defined amount of time. Mine (Subaru) has 121K miles and is working fine. One way to tell is to install an air/fuel ratio gauge. You will get used to watching it bounce around when the fuel computer system is in closed loop mode. I believe that when the speed of the "bounce" starts to degrade, then the O2 sensor is degrading. Have to keep in mind that different types of driving will cause different frequencies of bounce, i.e., 3/second for parking lot speed, 20/second for highway- this may be vehicle/brand dependent - that I don't know.
You only need to replace when a scan check of the engine tells you to. These can be very expensive and often replaced for no reason when it was something else that was the problem. A bad O2 sensor is usually the result of some other thing, like never tuning up the engine or using poor fuel, dumping all kinds of fuel additves to you gas. My 1992 Chevy truck went 76,000 miles and 11 yrs before the O2 sensor ws deemed shot but I also went that long on the original plugs, cap and wires.
I have 2 on my car. One has about 280,000 km on it. The second was replaced once and has about 120,000 km on it. If they fail, my ecu tells me. So you can see the wide variation in its lifespan - it all depends on how well the engine is maintained in top tune since contmaination is supposed to burn off these things anyways.
The O2 sensor can either fail or just become lazy (doesn't keep up as well with changing driving conditions). If it fails you'll get a check engine light. If it becomes lazy, you'll get poor fuel economy in city driving conditions. Don't worry about it unless you have poor fuel economy or a check engine light.
Some ECUs wont give you a 'check engine' warning until the o2 Sensor has completely carked it. In my Nissan Workshop Manual it states that if you hold the engine at 2000rpm in Neutral, the voltage should fluctuate (Rich->Lean->Rich) more than 5 times in 10 seconds. Ie 2 times is (Rich->Lean->Rich->Lean->Rich). Any less and the sensor is 'too lazy' as people put it and needs to be replaced!
For the record, my car has 110,000kms and it was changing about 7 times in 10 seconds... Perhaps people could use this idea to check how lazy their sensors are...
For the record, my car has 110,000kms and it was changing about 7 times in 10 seconds... Perhaps people could use this idea to check how lazy their sensors are...
O2 sensors wear gradually and your CEL won't come on until the thing is toast....meanwhile your fuel economy and performance will degrade with time. Remember, these things are in the line of exhaust fumes. Their response degrades with time and mileage. They are reponsible for seeing that the fuel/air mixture is proper/ideal for the conditions/load so that you're not running too rich or toolean.
I think 100k mi. (160k km) is a good interval. These things don't last forever, however I wouldn't change them more frequently than that. The reasons include improved power and engine running, catalyst life and preventing seizure of o2 sensor in the cat.
I think 100k mi. (160k km) is a good interval. These things don't last forever, however I wouldn't change them more frequently than that. The reasons include improved power and engine running, catalyst life and preventing seizure of o2 sensor in the cat.
I agree with 80-100K intervals. They don't just break, they slowly degrade. I replaced mine original at 160K and it was very dead.
And one more thing --- use OEM sensors! Not after market stuff like Bosch which doesn't last as long.
And one more thing --- use OEM sensors! Not after market stuff like Bosch which doesn't last as long.
There is a all purpose out of the car test using a volt meter and a propane torch on the O2.
1 Heat the O2
2 The O2 should read .6V in under 20 secs.
3 remove torch
4 The O2 should drop to zero in under 4 sec.
5 reheat for 2 minutes. There should be no drop outs or strange readings.
If it passes it is good. When I converted a car to EFI I used this at the wreckers. Most O2s failed, a few where good, and a few excellent. Most of the cars must have been running from memory.
1 Heat the O2
2 The O2 should read .6V in under 20 secs.
3 remove torch
4 The O2 should drop to zero in under 4 sec.
5 reheat for 2 minutes. There should be no drop outs or strange readings.
If it passes it is good. When I converted a car to EFI I used this at the wreckers. Most O2s failed, a few where good, and a few excellent. Most of the cars must have been running from memory.
Hummmmmm, that test isn't in my shop manual. Mostly it has scary warnings about checking it with a multimeter. I can see how your test should work, and checking the resistance ruin the thing. Could save those of us without a Tech 1 big dollars and hours of work. Thanks.
The O2 sensor of my previous car '91 Honda Civic was replaced at 150K miles. The noticeable sign was when I accelerated from stop and there was a period of hesitation before engine picking up speed. It was a very costly repair for sure.
On an LT1, that would be the EGR valve.
Just changed my front O2s at 80k, city mileage is unchanged as I have an exhaust leak, but highway mileage went up 17%.
O2 sensors wear gradually and your CEL won't come on until the thing is toast....meanwhile your fuel economy and performance will degrade with time. Remember, these things are in the line of exhaust fumes. Their response degrades with time and mileage. They are reponsible for seeing that the fuel/air mixture is proper/ideal for the conditions/load so that you're not running too rich or toolean.
This was exactly my experience with my '97 Maxima SE 5-speed. At 102k miles my SES light came on. I pulled the code, O2 sensor. Replaced the two up front (one per cylinder bank) and the rear (this one doesn't effect ECU operaton). While before replacement I noticed a flattened torque curve between 3000-3800 rpms, hesitation at 1200 rpms in 2nd gear doing a hard right hand turn in town and every now and then some clutch shudder on launches.
The new O2 sensors cleared all that and gave quite a marked improvement in engine power and responsiveness. The thing about them is that they deteriorate gradually over time and until you replace don't quite realize what you're missing.
BTW, it took 1000 miles before my ECU finally reprogrammed itself. Perhaps coincidentally I had put in some Techron the tank before the code cleared once and for all. I've regularly used Redline SI-1 additive in small doses each tank for past 35k miles. Perhaps one should put in a full bottle every now and then?
I bought OEM sensors. Replacement was straightforward except for front one, a really difficult one to get at and it sure seemed as if that one was not neversiezed at the factory during installation!
This was exactly my experience with my '97 Maxima SE 5-speed. At 102k miles my SES light came on. I pulled the code, O2 sensor. Replaced the two up front (one per cylinder bank) and the rear (this one doesn't effect ECU operaton). While before replacement I noticed a flattened torque curve between 3000-3800 rpms, hesitation at 1200 rpms in 2nd gear doing a hard right hand turn in town and every now and then some clutch shudder on launches.
The new O2 sensors cleared all that and gave quite a marked improvement in engine power and responsiveness. The thing about them is that they deteriorate gradually over time and until you replace don't quite realize what you're missing.
BTW, it took 1000 miles before my ECU finally reprogrammed itself. Perhaps coincidentally I had put in some Techron the tank before the code cleared once and for all. I've regularly used Redline SI-1 additive in small doses each tank for past 35k miles. Perhaps one should put in a full bottle every now and then?
I bought OEM sensors. Replacement was straightforward except for front one, a really difficult one to get at and it sure seemed as if that one was not neversiezed at the factory during installation!
When to replace the O2's? When your gas mileage drops off and a change of plugs doesn't restore the gas mileage. Usually between 90 and 120K. Like someone said, an O2 failure is usually caused by a problem of too much gas being dumped in the exhaust, such as a non firing plug, bad computer, or faulty injector.
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