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Oxygen Sensor

Discussion in 'LH: Large Cars, 1993-2004' started by Bens90W150, Jul 24, 2012.

  1. Bens90W150

    Bens90W150 New Member

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    My wife's 2000 Concorde LXI 3.2 V6 118K miles is dirtying the oil . Car runs great, but oil is almost black after 5000 miles. I'd like to replace the 2 upstream oxygen sensors. Advance carries Denso, Bosch, Delphi, NGK. I would like to buy the best quality sensor. Anyone had a particularly good expereince with one of these? If not, what have you had good experience with? thanks, Love Mopar, Ben
     
  2. fjb37

    fjb37 Member

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    I would think that the oil should be black at 5000 miles. The oil in my 94 GC 3.3L is quite black at 2500 miles and the engine just turned 90K miles. If you don't have a CEL, I don't think you have an O2 problem.

    That being said, I have used Bosch O2 sensors without a problem. I'm sure that some others on this forum will curse Bosch sensors but I would have no reason to do so. Just my $0.02.

    FredB
     
  3. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    You have no indication that you should replace the O2 sensors, you'd just be wasting your money. And I agree, after 5K miles the oil will be dirty.

    If you haven't replaced the PCV valve in the last 15K miles, do so. That more than anything can cause dirty oil.
     
  4. ImperialCrown

    ImperialCrown Moderator
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    Oil life and oil appearance can be 2 separate things. A lot depends on the environment, climate and driving duty. It may be just good detergent action taking place.
    I would more suspect a component that usually won't set a fault code like the PCV valve and rotted, collapsed rubber PCV/breather hoses.
     
  5. Bens90W150

    Bens90W150 New Member

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    "I would think that the oil should be black at 5000 miles. The oil in my 94 GC 3.3L is quite black at 2500 miles and the engine just turned 90K miles. If you don't have a CEL, I don't think you have an O2 problem."
    Hi Fred,
    The car is not generating a code, assuming a CEL is a code. The 3.2 and 3.5 are basically the same engine. I have a 2000 Intrepid with the 3.5 and 154K miles and a 2000 Concorde with the 3.2 and 118K miles. The oil in the 3.5 Intrepid is not black after 5000 miles. It is a medium brown, but you can see thru it. It still looks serviceable. The oil in the 3.2 Concorde is black after 5000 miles. It is not sludgey, but it looks unserviceable. I have changed the spark plugs on both cars and had both of them run with a fuel injection cleaning machine at a local shop. Both cars run fine and have good power. But the 3.2 concorde has less miles. It should have less dirt in the oil. I don't know anything about the 3.3 V6. I suspect it is sequential multi-point fuel injection. I do know that I have owned 4 Chyrsler SMPI cars and none of them had black oil at 2500 miles. I have had carburated cars do that, but never SMPI. I respectfully disagree that it is OK for oil to be black after 2500 miles. Thanks for the word on Bosch, Ben
     
  6. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Well, I've experienced both. My 84 Daytona Turbo Z has clean oil after 3K miles, but my 92 Daytona's synthetic oil is black about 500 miles after an oil change. Is something wrong? No. It still gets 32 mpg and runs flawlessly. There's just dirt that about 15 oil changes has not removed.

    I was a proponent of Bosch O2 sensors, never had operational problems. But when I went to remove one, the socket rounded off the hex and it's stuck in the manifold. Reason is, the Bosch sensor is about 1/8" longer than other brands, and the socket won't bottom out enough to grab all of the hex. For that reason, I won't buy one again.

    Also, the Bosch sensor has 4 long slots cut in the sensor portion. Denso and other brands have 16 stamped holes to expose more of the sensor to the exhaust, which should give better response, no matter how the sensor is oriented in the manifold.
     
  7. Bens90W150

    Bens90W150 New Member

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    Hi All,
    Regarding Oxygen sensors, I went to a Chrysler auto tech school in New Jersey back in the 1990s. We were taught that O2 sensors were a regular maintenance/tune up item at 100K miles. We were taught that they could go pretty far out of spec before setting a code so that they could be part of a no code issue, such as a car running dirty. I admit that I haven't worked in the automobile business since 1999. My info may be outdated, but I just retook the ASEs because of a recent job search. I'm pretty sure that my Motor Age study materials reiterated what I was taught back in the 1990s. Is your opinion that I should only replace an O2 sensor if it sets a code? Thanks, Ben
    I checked my records. I last replaced the PCV 12-2-10, Purolator PV 1050, approximately 26000 miles ago. My Haynes Manual 1998-2003 LH says to replace PCV every 24 months or 30000 miles. If Bob is right about every 15000 miles, my PCV is certainly out of spec. As a matter of general maintenance, should I be replacing my PCV every 15000 miles?
     
  8. ImperialCrown

    ImperialCrown Moderator
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    An OEM PCV valve should really only be replaced if it can't keep up with the blowby.
    It should hold a business card on the end of the breather hose at idle from the suction inside the motor. If the card won't stick, there is either excessive blowby or the PCV is failing. Watch for collapsed vacuum hoses, they soften as they age.
     
  9. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    It's only my personal standard to change the PCV valve that often, because it's so easy to do and cheap, and protects expensive synthetic oil.

    As far as O2 sensors, I can't see replacing them proactively. I track all of my gas mileage readings in a spreadsheet, so if fuel economy goes down, I know to start looking.

    On my last car, the O2 sensor lasted 190K miles, and it was the heating element that failed. Up until then, all emissions readings were the same as new. I replaced it with Bosch, and when I pulled the engine out 118K miles later, it was giving the same gas mileage and emissions as new. So I think it's a waste to change them at intervals.
     
  10. Bens90W150

    Bens90W150 New Member

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    On the PCV: I tried the vacuum test. Vacuum is excellent. I pulled the PCV and shook it. It sounded like new. I pulled the PCV hose and breather hose (no breather filter). I blew thru both: no evidence of sludge or clogging. I ran a wire down the crankcase gas fitting at the left side of engine (opposite end of PCV hose): no evidence of sludge or clogging. Hose tightness at PCV was weak. Could a vacuum leak around the hose end at the PCV cause an engine to have black oil when in the past, the oil had not been black at time of oil change? This 3.2 V6 in my Concorde has had dark brown oil in past at time of oil change: every 5000 miles. It is now black at time of oil change. Again: no performance issues whatsoever with this car at 118K miles, 12 years old.
     
  11. ImperialCrown

    ImperialCrown Moderator
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    Swollen, loose or dry rotting PCV hoses should be replaced. They are formed hoses and best replaced with the proper formed hoses available from Chrysler. Trying to make a regular hose work may cause kinking and poor fitting ends.
    Shaking a PCV and listening for a rattle is no longer really a valid test. Its performance in operation is.
    Oil stains in the air cleaner at the breather end or on the filter itself tell a story that the PCV is not working as well as it should.
    There is a fault code for O2 sensor stays at center, O2 reads high, O2 reads low and the O2 heater failure for all 4 sensors. The 'stays at center' fault means that the O2 is no longer reactive and is at the end of it's life.
     
  12. Bens90W150

    Bens90W150 New Member

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    Interesting, Advance and NAPA do not list a PCV hose exact fit to the car, even though the crankcase fitting is smaller in diameter than the PCV. I guess I will have to check with a Chrysler dealer. The question remains: would a loose fitting hose at the PCV cause a car to dirty the oil much more than it used to?
     
  13. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Since it will be an air leak, it will not apply as much vacuum to the PCV valve, so it won't operate as efficiently. So, yes, probably.

    If you measure the inner and outer diameters of the PCV hose, you can usually get replacement hose at NAPA or other parts stores, and trim to length. Make certain to specify "emissions hose" or "oil-resistant" hose, as regular rubber hose will disintegrate within months.
     
  14. ImperialCrown

    ImperialCrown Moderator
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    These are specially formed and molded hoses. You could 'make one up' with various elbows and reducer/adapters, but for proper fit a factory Mopar one would be best.
     
  15. patricklynch

    patricklynch Mopar starship captain

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    You can still do the key dance for these cars. I just did that for my new-to-me 2002 Concorde Lxi. My check engine light is on all the time. The key dance revealed the following codes--P0132 (1/1 oxygen sensor shorted to voltage) and P0152 (2/1 oxygen sensor shorted to voltage). If you haven't tried that, it's the same as the EEKs except that you don't have to count the flashes of the check engine light, you can get a straight up easy to read code.
     

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