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Do I need an oil change?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jk823, Nov 30, 2011.

  1. jk823

    jk823 Junior Member

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    In June I changed my oil and rotated my tires at the 30K mile mark in my 2009 Prius. From June until about mid-August the car was driven only intermittently (less than 1K miles) and since August it has been garaged as I've been working out of town.

    I have had friends go in and start it up for 20-30 minutes every 2-3 weeks but I'm going to go back home and drive it again and so was wondering -- do I need to get the oil changed and tires rotated again? Technically it is WELL below the 5K mile threshold, but it has been 6 months since the last oil change. What do people here think?

    Thanks!
    John
     
    #1 jk823, Nov 30, 2011
  2. uart

    uart Senior Member

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    You definitely don't need to rotate the tires.

    If you're likely to take it for a drive long enough to get the oil fully up to temperature when you get home (>30 minutes) then I'd do that and then take a look at how the oil looks on the stick. I think it should be ok.

    BTW, what brand/type oil are you using?
     
    #2 uart, Nov 30, 2011
  3. jk823

    jk823 Junior Member

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    Thanks! I should be taking it for a longer drive when I'm back so I'll plan on checking out the oil. Forgive the stupid question, but what should the oil look like? Or put another way, what signs should I be looking for that I might want to replace the oil?

    As for the type, I've been using whatever conventional oil (not synthetic) they use at Midas. Does that change the answer at all?

    Again, I appreciate the advice!
    J
     
    #3 jk823, Nov 30, 2011
  4. efusco

    efusco Moderator Emeritus
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    Personally, I wouldn't change the oil. I run Mobil 1 0W-20 synthetic 10K miles (and have done several UOAs showing great oil life left at those intervals) so only change about every 9 months or so. If you used conventional oil and depending upon storage conditions (was it really hot or cold or humid?) then it might give you a bit of piece of mind to do so, but I highly doubt it is "necessary".
     
    #4 efusco, Nov 30, 2011
  5. jk823

    jk823 Junior Member

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    It has been stored in Los Angeles so not too hot/humid or cold. It sounds like I should be good until 35K?
     
    #5 jk823, Nov 30, 2011
  6. Ancient Nerd

    Ancient Nerd Junior Member

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    What does it say in the car handbook? here in the UK, the service interval is 10,000 miles, or one year, whichever comes first. So you won't hurt the car if you leave it a year, especially with synthetic oil.

    However, if the US requirement is for less, and you have a warranty that says you must service in accordance with manufacturers specifications. then do what the book says.
     
    #6 Ancient Nerd, Nov 30, 2011
  7. tv4fish

    tv4fish Member

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    The oil "should" look almost like it did when it was poured into the engine :) Maybe a little dirty/discolored. If you start and run it for a while and then pull the dipstick and it looks "foamy" on the dipstick -- change it. (I doubt that it will however.)
     
    #7 tv4fish, Nov 30, 2011
  8. efusco

    efusco Moderator Emeritus
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    I do think that's a good point--if you're still under the ICE's warranty you should go "by the book" just in case there's an engine related problem so they don't try to deny you for lack of a $20 oil change. So, an '09 with < 36k you are clearly still under warranty so that's probably the smart move.
     
    #8 efusco, Nov 30, 2011
  9. uart

    uart Senior Member

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    Motor oil doesn't really deteriorate very much from just sitting in the engine. The main concern is that frequent cold starts without driving long enough to fully heat the oil contributes to formation of acids in the oil, as well as fuel and water contamination. Motor oil however is formulated to fight (neutralize) these acids (up to a point), so with starts only every 2 to 3 weeks you should be fine. Additionally, regarding the water and fuel contamination, simply driving the car for long enough for the oil to attain full operating temperature is enough to eliminate these from the oil. When the oil is up to temperature these come off as vapor and the engine crankcase ventilation system is designed to draw them off and burn them.

    Just remember that the oil takes significantly longer than the engine coolant does to get up to temperature. You'll really need to drive for about 30 minutes or more before the oil is close to full operating temperature. And if that driving is under easy conditions for the Prius were the engine is cut off half the time then it will take even longer.
     
    #9 uart, Nov 30, 2011
  10. cyberpriusII

    cyberpriusII Prodigyplace says I'm Super Kris

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    I change my oil every six months. I think that's what the manual calls for (6 or 5K).

    My manual got somewhat soaked with mouse pee, so I don't keep it in the car anymore....not even sure where it is anymore. :rolleyes:

    I less than a thousand miles a month....when I change the oil it looks almost new.

    Change it anyway, with whatever NAPA or Bi-Mart has on-sale. Normally Chevron...with an NAPA silver filter.
     
    #10 cyberpriusII, Dec 4, 2011
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