o2 sensor lifespan?

[Strattos]

I'm chasing down the cause of a surging idle problem and still need to check for vacuum leaks and MAF issues, which from searching the forums seems to be a common cause.

However, I was talking to a mate about it and he reckons it's more than likely the o2 sensors on my headers, as they only have a 100k lifespan.

Is this right, the 100k lifespan? My car's done close to 130k atm.

The problem started after recently having to raise the motor to replace engine mounts. Ever since it's had this surging idle. not sure if I've bumped the o2Sensors while buggering around down there, or if one of the vacuum hoses at the top end has stretched too far when the motor was being lifted.

It doesn't happen when the motor is stone cold, or when its at operating temp, only seems happen in that mid-temp range. However the motor just doesn't feel as sweet as is normally does throughout the rev/temp range, so something is definitely wrong.

[SirHenry]

I've my AU S1 since 70k its now got 260k and 8 years later and I have never replaced my O2 sensor.

I know I lot of people swear by it, just depends on the car I think they all seem to have their things mine hates unleaded fuel.

[CRAIGAU3220]

Mine were becoming lazy (hunting idle) from time to time at 50k!

Replaced and all is good.

[b2tf]

100,000kms max.

[Revolver]

Originally Posted by b2tf

100,000kms max.

Man, mine are at least 150k. Possibly the full 428,000

Don't seem to have an issue with mine? Other than chewing through LPG like no mans business. Petrol mileage is pretty good though.

[rowan194]

I changed mine around 180,000km when trying to figure out high consumption. Didn't make one bit of difference, so the old one was probably just fine.

[Strattos]

Thanks for the replies fellas.

[blumx]

My AU111 has done 175,000klms and still on the original O2 sensor and car is running fine.

[RG]

They're a consumable and are only rated to 100k, the same as many other parts.

Just because you haven't replaced them and the car is still running doesn't mean that they're fine. My bet is if you replace them you'll notice an improvement in at least fuel economy and if they're bad idle too.

[madmelon]

The Bosch catalogue (linked below) suggests a replacement interval of 250,000km for the AU V8 Falcons in the catalogue next to the part number. This contrasts with a suggested replacement interval of 160,000km for the type of sensor used (4 wire planar), which is listed in the introduction/explanation of sensor types.

http://www.bosch.com.au/car_parts/en...r__Cat_WEB.pdf

I've got 130,000km on my XR8 at the moment and the fuel consumption has skyrocketed- struggling to get more than 360km from a tank and I used to easily get 450km so this is something I'll be checking.

[Strattos]

Since my first post I've checked for vacuum leaks, and as far as I can tell haven't got any.

Also plugged a scanner into to see if any errors popped up, and nothing's ringing any alarm bells, so the 02 sensors are my next port of call.

Are there any tricks/pitfalls to fitting them?

Is it as simple as disconnecting and unscrewing the old ones and screwing in and connecting the new ones? Do I need to use any type of sealant?

[b2tf]

Originally Posted by Strattos

Are there any tricks/pitfalls to fitting them?

Is it as simple as disconnecting and unscrewing the old ones and screwing in and connecting the new ones? Do I need to use any type of sealant?

No. Undo old ones, unplug and fit new ones. No sealant required.

[rowan194]

They can be a bit fiddly to remove if you don't have an offset spanner. I think the size was 22 or 23mm. I didn't have one, couldn't get an adjustable wrench in there, so I ended up removing the exhaust manifold to remove it. You can use your new O2 sensor to determine the correct spanner size.

[madmelon]

Size is 22mm, did it on Wednesday. Remove intake to get to passenger side with greater ease.

[mik]

I'm on my second o2 sensor, put in the newy at approximately 150000, i suspect their service life is dependant on the rate at which they become grotyed up, ie a highway car it lasts a long time , a city car lots of stop starts = shorter service life, also as the engine becomes a bit tired with a lot of miles, i'm guessing oil contamination from oily exhaust fumes would shorten the service life also.

[sly]

One simple way to check if the O2 sensor is working is to just fill your tank to the brim. This will fill up the fume canister which will purge like buggery into the intake. If the car runs like a hairy goat for 15km or so afterwards, the O2 sensor isn't able to respond to the suddenly richer mixture.

This works for wagons at any rate, dunno about sedans or utes. It takes about 10 minutes to brim fill a wagon, it takes an extra 15 litres or so after the nozzle clicks off.