|
|
|
#1
|
|||
|
|||
Are oxygen sensors a maintenance item, like spark plugs?
The service manual on my 1999 BMW 528i says to replace the oxygen sensors every 100,000 miles. Is that customary? I always thought you replace those when they went bad.
By the way, the BMW dealer quoted me about $330 per sensor. NAPA and Carquest sell them for about $65 a piece. They both sell Bosch, which is the same brand the dealer sells. My car has 4 sensors, so that is quite a difference. |
#2
|
||||
|
||||
You should get an OBDII "CEL" light when the sensor(s) need replacement. Yes, the price range is really incredible. Bosch sensors were used on a wide range of vehicles, so you're going to get the best deal from a parts shop than the dealer. For instance, on the W201/W124 cars, the Bosch O2 sensor was the same as used on later model Ford's V-8 Mustangs, and that FoMoCo part was a fraction of the MB part. Just had to adapt the wire harness.
|
#3
|
||||
|
||||
They'll go bad after time but you'll know from decreased mileage, running rough, poor performance, etc. Should throw codes too AND the code will point to which one is bad. I would replace when they go, no need to spend the extra money.
__________________
TC Current stable: - 2004 Mazda RALLYWANKEL - 2007 Saturn sky redline - 2004 Explorer...under surgery. Past: 135i, GTI, 300E, 300SD, 300SD, Stealth |
#4
|
||||
|
||||
It is a maintenance item but I have yet to replace them on either of my 210s and both are over 100k. I will eventually replace them as preventative measures but I've got other things on the list first.
Sometimes the cheap ones from NAPA, etc require crimping your own wires. Not a big deal but some extra work for you (but results in pocket book savings).
__________________
2009 ML320 Bluetec 1985 300CD 1981 300TD Past Mercedes 1979 300TD 1982 300TD 2000 E320 4Matic Wagon 1998 E430 1984 300SD 1980 300SD |
#5
|
||||
|
||||
I'd think by 99 the computer would be smart enough to tell when the O2S is bad.
-J
__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket Tesla Model 3. 205,000 miles. Been to 48 states! Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels. 2014 Cadillac ELR 2013 Fiat 500E. |
#6
|
||||
|
||||
The O2 sensor does one thing...measure emissions.
Spark plugs gradually degrade to the point of adverse performance. O2 sensors probably degrade to where they relay inaccurate information, so the adjustments performed by the engine management systems don't allow the engine to run optimally, or the emissions end up outside of allowable parameters...which in turn sets of the CEL.
__________________
2009 ML350 (106K) - Family vehicle 2001 CLK430 Cabriolet (80K) - Wife's car 2005 BMW 645CI (138K) - My daily driver 2016 Mustang (32K) - Daughter's car |
#7
|
||||
|
||||
I (under the watchful eye and guidance of John Hef) replaced the 02 sensor in Maxine the Wonder Benz at 175,000. If it's not broken don't fix it.
__________________
"It's normal for these things to empty your wallet and break your heart in the process." 2012 SLK 350 1987 420 SEL |
#8
|
|||
|
|||
O2 sensors go bad gradually over time. When they do the inaccurate readings they generate tend to make the car run rich and get less good fuel economy. They have to be pretty bad before they will start setting codes though. If you're still getting good mileage and have no codes, I wouldn't worry about it. OTOH if you're mileage is suffering and the other usual suspects check out, it might be time to start thinking about your O2 sensors.
__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar. 83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles 08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles 88 Jaguar XJS V12 94,xxx miles. Work in progress. |
#9
|
||||
|
||||
Replaced both on the Mustang after getting a code thrown by one...kinda figured it's best replacing in pairs anyway.
They run $50-60/apiece at AutoZone...made by Bosch. 15 minute DIY...
__________________
2009 ML350 (106K) - Family vehicle 2001 CLK430 Cabriolet (80K) - Wife's car 2005 BMW 645CI (138K) - My daily driver 2016 Mustang (32K) - Daughter's car |
#10
|
|||
|
|||
Well if you where able to measure and compare them to a new one. You would know if the time to change them was coming.
The computor should only throw a code once they exceed their design paremeters range excessivly. They could be close for a long time prior to doing that. A pretty well total failure is basically what the computor is set up to indicate. A friend of mind changes his by milage to keep his fuel milage optimum. He does not seem to mind the cost. I. have to assume he keeps a pretty good track of his fuel milage, He told me it was benificial in his case. |
#11
|
|||
|
|||
Would a bad O2 sensor allow the air/fuel mixture become rich enough to fry the catalytic convertors? That might be an argument to replace them before failure if that is true.
|
#12
|
||||
|
||||
Yes but again it would be throwing a code long before that happened. That also assumes the other O2 sensors fail simultaneously (most newer cars have several).
__________________
TC Current stable: - 2004 Mazda RALLYWANKEL - 2007 Saturn sky redline - 2004 Explorer...under surgery. Past: 135i, GTI, 300E, 300SD, 300SD, Stealth |
#13
|
||||
|
||||
Depends.
My former W124 never threw a code, but had misfiring issues and wouldn't pass emissions at one time. Turned out to be bad plug wires. Actually one wire was worn bad to the point that the plug attached to it fouled, and enough unburnt fuel went out the exhaust and foul the O2 sensor...all the while never throwing a code!
__________________
2009 ML350 (106K) - Family vehicle 2001 CLK430 Cabriolet (80K) - Wife's car 2005 BMW 645CI (138K) - My daily driver 2016 Mustang (32K) - Daughter's car |
#14
|
||||
|
||||
Quote:
__________________
TC Current stable: - 2004 Mazda RALLYWANKEL - 2007 Saturn sky redline - 2004 Explorer...under surgery. Past: 135i, GTI, 300E, 300SD, 300SD, Stealth |
#15
|
|||
|
|||
I agree. I also wonder whether a bad O2 sensor could caused the mixture to be rich enough to affect the lubrication of the upper part of the cylinders.
|
Bookmarks |
|
|