Excessive oil consumption: Does using thicker oil help?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Preeeus, Jan 9, 2019.

  1. Preeeus

    Preeeus Member

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    Our Prius is experiencing oil consumption of about 1qt/850mi.

    For those who are experiencing excessive oil consumption, has switching to a different oil viscosity helped?

    If so, what viscosity oil worked best? And did you switch from synthetic to dino oil or even HDEO? Also, any side effects to report?
     
  2. Krusty195

    Krusty195 New Member

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    Im having a similar issue. Sometimes changing the pcv is all it takes to eliminate a good portion of oil consumption. Unfortunately for me it helped some but still burn quite a bit
     
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  3. RightOnTime

    RightOnTime Senior Member

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    Look into Lucas High Mileage Stabilizer additive. Drastically helped with Burning oil consumption for cars at our Shop.
     
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  4. tankyuong

    tankyuong Active Member

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  5. Preeeus

    Preeeus Member

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    Thanks. Since the Prius generally takes synthetic oil, which is better for it: the Lucas Synthetic Oil Stabilizer, or the Lucas High Mileage Oil Stabilizer?

    Any idea what the result should be (burning 1qt/850mi now)?
     
  6. RightOnTime

    RightOnTime Senior Member

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    We used 1/2 a bottle of high mileage stabilizer for a car that was burning 2 quarts per 1000 miles. Works wonders.


    iPhone ?
     
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  7. Preeeus

    Preeeus Member

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    Thanks. Why only a half bottle instead of the full bottle? Do you use it at every oil change, more frequently, or less frequently?
     
  8. RightOnTime

    RightOnTime Senior Member

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    Every oil change. If it burns more oil we have the option to use the complete bottle.


    iPhone ?
     
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  9. Preeeus

    Preeeus Member

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    Thanks so much for your ideas and help. We are concerned that if we don't do something, the catalytic converter and/or oxygen sensors will fail.

    Would you be willing to help more?

    Right now, we have Mobil 1 5W20 full-synthetic oil with about 5.5K miles on it. But not really... since we've added 1qt every 850 miles... so we've added 6.5qts since the last oil change (in an engine that only holds 4.2-4.4qts, depending on who you ask). The oil level is about 1.3qts low right now.

    The oil on the dipstick is dark in color, which we've heard can happen with blowby caused by bad Toyota piston rings, which we suspect we have (but aren't sure).

    We do think there is a small oil leak somewhere, because we saw a few fluid drops on the ground after we parked on a driveway overnight.

    So, we have to decide on a plan. Here's what we're thinking:
    1. Contact Toyota Headquarters and file a problem report in case Toyota decides to do an extended warranty for this problem (many people seem to have this problem, and Toyota reportedly did an extended warranty for a similar problem with the Camry).
    2. Add 1qt of Lucas High Mileage Oil Stabilizer now
    3. Check the oil level weekly
    4. As oil is needed, top off with 5W30 full synthetic (which will be mixed with the 5W20 currently in the engine). Should it be a "high mileage" oil or not?
    5. Continue step 4 until there is 10K miles since the last oil change.
    6. Get an oil change with 5W30 full synthetic and a new oil filter and a half-bottle of Lucas High Mileage Oil Stabilizer. At the same time, have the oil pan gasket inspected/replaced.
    7. If oil consumption is still an issue, add another half-bottle of Lucas High Mileage Oil Stabilizer. If that doesn't help, try another half-bottle.
    8. If it's still an issue, try a piston soak product or perhaps Seafoam. Any recommendations?
    9. If oil continues to go down, bring in the vehicle to a mechanic to get the PCV inspected/replaced.
    10. Anything else?
     
    #9 Preeeus, Jan 10, 2019
    Last edited: Jan 10, 2019
  10. cnc97

    cnc97 Senior Member

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    Your information is lacking 2 important details that I need before adding my .02. Year and mileage of your car. However I did substitute a known value (mine) and came up with a solution. My car is a 2010 and is at nearly 220k. (I already did my swap but, for the sake of this, let’s assume not.)

    In this instance I would find a used engine very soon. I’d be prepared for yours to fail without notice. For me personally, consumption of a quart before 1000 miles is a severe issue. Oil consumption that quickly should be leaving a cloud behind you, or a haze on your rear glass. I noticed that the last week to ten days before my engine expired, but ignored it. Something is terribly wrong in the engine and it is unlikely that oil additives are going to stop it. I believe that your best bet is to rebuild or replace your existing engine sooner then later.
     
  11. Preeeus

    Preeeus Member

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    The Prius is a 2010 with 145K miles. Vehicle drives perfectly, and no indication of a problem except when checking the dipstick.

    Where do you find a used engine with low miles? From what I've read, this problem with this model Prius engine is common, especially once an engine hits about 115K miles. So a used engine would have to be completely rebuilt or have very low miles.
     
  12. tvpierce

    tvpierce Senior Member

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    I have the same amount of consumption with my 2013. Heavier oil didn't make a difference. I tried 10W-30, 15W-40, and 20W-50 (during summer) with no change in consumption. I've given up on synthetic simply because of cost. I now use conventional oil and change it at 5K miles.
     
    #12 tvpierce, Jan 10, 2019
    Last edited: Jan 10, 2019
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  13. tvpierce

    tvpierce Senior Member

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    What product did you use?
     
  14. cnc97

    cnc97 Senior Member

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    The used short block(block, pistons, crankshaft, etc) that I put in mine is from a 2016 that had 8-10k miles on install. I found it using Car-Part.com--Used Auto Parts Market . That is one of several sources for used engines.
     
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  15. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Has anybody been thoroughly under it to determine leak vs. burn? Burning a quart of oil in 850 miles generally indicates a severe engine problem, but leaking it? That could be a very minor thing.

    Some careful time with a lift and lights would probably reveal the difference between needing an engine or a seal.
     
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  16. Georgina Rudkus

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    While using a higher viscosity oil might have some effect in reducing blowby through the oil rings of the pistons, there are many other negative effects,

    Engine oil and it's flow through narrow passages including the oil supply to the timing chain both lubricates and cools these engine areas. Using a higher viscosity oil slows the movement of oil resulting in less lubrication and cooling. Heat also destroys seals.

    I would only use a "high mileage" 0W20 oil.
     
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  17. Aaron Vitolins

    Aaron Vitolins Senior Member

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    I was reading a thread on here about pistons soaks. They can really help especially if you can not use the car for a few days. Definitely look into that. That's what I would if Toyota doesn't help out in anyway.
     
  18. farmecologist

    farmecologist Senior Member

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    Darn another 2010 with oil consumption issues. Seems like a trend here. :(

    You are nearing the point where Toyota *may* help you out. However, I think the official cutover from the manual is around 1 quart per 600 miles ( which is downright insane ). Note that Toyota will run 'tests' on your vehicle to verify. It would not hurt to contact Toyota corporate to see what they say.
     
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  19. sam spade 2

    sam spade 2 Senior Member

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    Oil is oil. In an older vehicle, there is little or no good reason to spend the extra money on synthetic, especially if you are increasing the viscosity.

    A heavier oil by itself probably won't do much.
    A lot of companies make "high mileage" oil with the additives already in them, some synthetics even.

    If you are using a really LOT.....like a quart in less than 1000 miles.......you really should inspect for leaks.
    And then don't be afraid of increasing the bottom and top numbers on your oil both by 20 points.
    That is, if the cap says 0W20, a 10W40 or 15W40 or even a 20W40 should be fine.
     
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  20. Preeeus

    Preeeus Member

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    We bring it to a mechanic (who we think is good) for oil changes. He didn't notice any issue when the vehicle was lifted, but we didn't specifically instruct him to look for issues (we should have, in retrospect). Maybe that should be towards the top of the list.

    On the other hand, the oil is very dark, which from what we understand implies blowby, hence consumption.
     
    #20 Preeeus, Jan 10, 2019
    Last edited: Jan 10, 2019
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