Haynes says it should be replaced at 50K miles interval on a 1989 brick.

I have over 158K miles, and the original O2 sensor. I am getting only 18 miles a gallon. Maybe the sensor is bad, and car running too rich?

Should I replace the sensor? A 50 to 100 dollars item.

What do you think.

Thanks for your input brickters.
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'89 244DL M47 158K miles

If you're getting only 18 miles to the gallon, there's something wrong here, and probably more than just the O2 sensor.

If you haven't done so, work your way through Chapter 1 of the Haynes book. Check your Fuel Pressure Regulator and make sure there's no trace of fuel in the vacuum line leading to it (otherwise you have a ruptured diaphram and the FPR must be replaced). Also pull your vacuum hoses and replace them if you find hard/firm hoses or hard/cracked ends where they push onto the nipples. Pull your accordian tube, bend and flex it while looking for hairline cracks. Also pull your IAC Valve and clean it well, make sure the valve swings back and forth easily when you quickly twist the motor body in your hand. Also change your air filter if you haven't done so within the last 2 oil changes.

Make sure the temperature sensor that goes to the computer is working properly (there is a seperate one that controls the dash-gauge). Also check for vacuum leaks around the intake manifold. Check for dragging or stuck brake calipers by putting your hand on each wheel after a drive (check for unusual heat buildup). And lastly, check the AMM if necessary (swap with a known good one if you have one, I keep a spare in the car next the spare Fuel Pump relay and Fuel Pressure Regulator).

On to the O2 sensor. Just because you can get a good voltage reading off the O2 sensor doesn't mean that it's good. As these sensors slowly die, the car will enrichen the mixture to compensate for a low output signal. The sensor will then come up to the proper voltage, but the car will be running rich to achieve this 'correct' output. The old sensors from the 70s and early 80s would last about 30,000 to 100,000 miles, but the newer ones can go much longer. You can kill an O2 sensor in about 5 miles if you have any kind of antifreeze contamination in your combustion chamber or silicon contamination. Running too rich for too long can also compromise it's output (like with a stuck IAC valve). For more info on O2 sensor life expectancies and how to test them, please read the following post:
http://www.brickboard.com/RWD/index.htm?id=683406

For my own personal vehicles, non-Bosch O2 sensors typically had a catastrophic failure after about 2 years or less. True Bosch sensors, have had a 5+ year reliable service record, however, I plan to replace my current Bosch sensor at about 5 years simply to keep the gas mileage up as best as I can. The new sensor will more than pay for itself in the long run.

Other sites to read that have relavent information:
http://www.homestead.com/volvo2/O2sensor.html

http://www.brickboard.com/RWD/index.htm?id=618018&show_all=1

God bless,
Fitz Fitzgerald.
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'87 Blue 245, NA 229K

The 50k replacement was for older models I don't think the Haynes manual(get the Bentley) is correct for your year. Not bad PM though has a bad O2 can cook the cat. The the challenge is getting it out if rusty. My 1990 lasted to 275K. Replaced it with a $50 universal Walker.

Thanks Yama.
My brick has 158K miles only and year is 1989, so based on your experience I should be able to go a bit further.

My mechanic told me that when O2 will go bad, I will know because a light will come on the dash ? Can you confirm that ?

How did you come to the conclusion that your O2 needed replacement ? Was that purely PM on your part ? Did a light come on ? Did you test it ?

In Haynes they say 50K miles for that year (45 miles for earlier model). On FCPGroton they say 30K miles for earlier years and 60K miles for 1989. All a bit confusing to me... Maybe Groton is only giving the life expectancy of their Bosh replacement part.

Was the original O2 sensor a Bosh in your 90 brick?
Have you seen any improvement in your gas mileage since you replaced the O2 sensor?
Thanks again Yama for your input.
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'89 244DL M47 158K miles

When my O2 senor went bad my check engine light did come on. The 2 fail codes displayed where 2-3-1 and 1-1-3. I did check it with a voltmeter. It went slow being intermittent for a while. Once it went totaly car was running very rich and rough. The rich condition is bad for the cat.(I need a cat. now) My sensor was orginal and believe it was a Bosh. It was very carboned up. I went with a universal 3 wire Walker. Its very easy to splice in and American made vs German. Volvo doesn't specify a replacement interval for our O2 sensor. 60K is to frequent but 150k is probably about right. Changing yours isn't bad PM. Mine was easy do get out because of rear main seal leak.(not all are) Haven't drove it enough to know on the mileage. Have you changed cap,rotor,plugs and air filter allready?

Hi Yama,

Yes I have bought my car from original owner at 155K miles (PO had done just the minimun, but did maintain the car, at Volvo dealer while car was under warranty, and at independant shop after that).

What I have done so far :

1) plugs (Bosh platinum)
2) rotors and distibutor cap, and ignition wires + coil (all Bosh)
3) air filter (Frame)
4) oil change and filter (Mann)
5) fuel filter (Bosh)
6) cleaned flame arrestor (and replace with plastic nipple from FCP Groton)
7) cleaned throttle body (with carb cleaner without taking off the TB)
8) ran a bottle of 44K in full gas tank
9) 4 new tires + front wheel alignment (non brand from Tire Plus)
10) muffler (from FCP Groton)
11) Front brake pads
12) Some light bulbs in dash and in emergency brake console
13) bought at junkyard a fuse cover that was missing
14) from junkyard got a new front hood hinge assembly on driver side (mine was bent when I got the car and broke after a few weeks)
15) I cleaned the air ducts and vents (removed them and cleaned them with soapy water), sprayed the ducts I could not remove with some Lysol -- now much beter smell when vent is on or heat

My AC is dead doesn't work -- I leave it that way for now, it's the winter anyway.
I am getting 18 miles a agllon with suburban driving (30 to 40 miles an hour mostly with lots of stop and go at red lights, stop signs and the like). I do drive about 200 miles a week.

I am might get another 10K with my timing belt, although it was last changed 60K miles ago, so maybe I'll have to do it before.

Next cheap maintenance on my least before year end :

1)I am going to change the temperature thermostat
2) 50/50 coolant/distilled water and replace some spongy hoses (say Yama, what kind of coolant do you put in your brick? some have recommanded Preston, others will not put anything else but Volvo type C, what is your feeling?)
3) Well here I was thinking of that O2 sensor, but my light has not come on yet.
4) Last items are confort-ride qulity, with struts and shocks, some bushings here and there, but that stuff might have to wait until the summer I'll just cope with the clunk and clink for now.

What about you? What you done so far? Do you recommand anything?




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'89 244DL M47 158K miles

There is no predictable or standard life of an O2 sensor except to say anywhere from 1k miles to 500K milles. It's like asking how long will my windsheid washer motor or fuel pressure regulator last.
I personally do not consider replacing it a smart preventive maintenance issue, it will not stop your car from starting or running. It can be easily checked during tune ups with an ordinary digital meter.
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David Hunter

Had my 1990 sedan since new. Currently has 276K. Just recently picked up a 1990 Wagon with 156K as a project car. I've always run the prestone anti-freeze with good luck. I do recommend that you use distilled water instead of tap or well though. Get it at Walmart for .50 a gallon. You might want to consider changinig diff. fluid, tranny fluid, power steering fluid and brake fluid. Your rear trailing arm bushing is most likely shot if it hasn't been done yet.

My recent notable repairs upgrades are:

1.) Tach upgrade wagon and sedan.
2.) Rebuilt bucket seats wagon and sedan.
3.) Replaced iky tan interior on wagon with black cloth from a 1993.
4.) Full fluid change wagon.
5.) Reinforce rear bumper wagon.
6.) Por 15 all rust spots wagon and sedan.
7.) Rear trailing arm bushing sedan.
8.) 15" wheels from 740/940 for sedan. (need to get hubcaps)
9.) Replaced cap, rotor, plugs and o2 sensor sedan.
10.) Replaced cracked tailights Wagon.

To do's:
1.) Replace cat on sedan to pass emissions.
2.) Tailgate wiring harness wagon.
3.) Replace door panels wagon.
4.) Complete redo rear suspension wagon.
5.) Windsheild wagon.
6.) Fuel sending unit wagon and sedan.

They last about 125k miles. You are overdue.