Why does there seem to be a serious oil burning problem?

Discussion in 'Gen 2 Prius Main Forum' started by T1 Terry, Jan 4, 2019.

  1. T1 Terry

    T1 Terry Junior Member

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    I wonder why there is common thread through all these problems of excessive oil consumption. I have a Prius with very high mileage that has only now required a replacement cat, yet there seems to be a regular call for help related to failed engines and cats due to high oil consumption.
    The fix for my Prius was an after market unit welded into the existing pipework, the fuel filter replaced, the codes cleared and the problems went away. It still drives great and I think the real trigger was a blocked fuel filter causing a lean run condition when highway driving and this cause excessive combustion chamber heat and exhaust manifold heat resulting in carbon deposits shifting and blocking the cat.
    Even with the very high mileage my Prius does not use oil between oil changes. When I stripped it down to change the timing chain (which turned out to be still serviceable as there was still some travel in the chain tensioner remaining and the guides were all good) the inside of the covers were all still clean, not covered in sludge build up.
    Could the base problem be lack of regular oil changes and the lack of use of an engine oil flush being added to the oil and the vehicle driven before the old oil was dropped. Naturally, the oil filter should be changed with every oil change because that is where the rubbish ends up.

    T1 Terry
     
  2. bisco

    bisco cookie crumbler

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    what the mileage?

    i have never noticed a ton of posts regarding gen2 oil burning

    gen3 seems to start with a clogged egr, and possible pistons and rings that aren't up to snuff. but there are plenty of high mileage gen 3's that don't burn oil, so who knows?

    i'm sure you will find similar complaints on any car site
     
  3. golfmk681

    golfmk681 Member

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    If a car burns oil at 100k I’d be concerned but over 200k I wouldn’t be surprised if it did burn oil.
     
  4. bisco

    bisco cookie crumbler

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    my daughters '08 doesn't burn any at 130k
     
  5. T1 Terry

    T1 Terry Junior Member

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    Maybe the ones with engine blow ups and catalytic converter blockage reported on these threads are not as common as it appeared to be by the reply comments. Maybe a poor servicing history is more to blame than a more deep rooted problem.
    As you can see from my signature window, my 2 Prius have relatively high mileage and neither of them use oil between changes.

    T1 Terry
     
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  6. golfmk681

    golfmk681 Member

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    is she selling it lol
     
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  7. padroo

    padroo Senior Member

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    Terry, did your Prius lack power on acceleration or at highway speeds. If it did I would agree with you but if not I don't. Then again fuel filters used to be considered part of routine maintenance but I don't recall fuel filters mentioned in the maintenance schedule. On old cars plugged fuel filters were common and they would hardly accelerate.
     
  8. bisco

    bisco cookie crumbler

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    it's at the local gas station now with a for sale sign. she picked up a suburb impreza for winter driving in the catskills
     
  9. The Electric Me

    The Electric Me Go Speed Go!

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    I was going to say, and it's already been said, but the reoccurring problem does seem to be with the Gen 3.
    And my observation is ALL engines will at some point start to burn oil..and various rates, on various timelines.
    If you have a higher mileage vehicle and it's NOT burning oil, just keep doing what you're doing and consider yourself lucky.

    As far as tying specific maintenance behaviors to specific outcomes?
    Far too big a grouping.
    As with everything mechanical, the better you maintain the better your reliability is likely to be.
    However, Oil Burning seems to come into play, prematurely for a lot of owners of Gen 3, regardless of Oil Changing routine.
     
  10. edthefox5

    edthefox5 Senior Member

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    How did you replace the fuel filter?

    You quote a very high mileage then don't post what the mileage is.

    If the fuel filter is blocked it would be lean alright so lean the car wouldn't run.

    I don't remember anyone maybe one or 2 over 11 years ever changing the timing chain. What were you chasing?

    Engine oil flush is never needed for a car whose oil is maintained correctly. Haven't ever used that stuff over 40+ years of car ownership.

    Lastly my suspicion on oil use is the engines are basically ruined if the car is 100% dealer serviced oil change. Dealer never checks it before the change to let the owner know they were a quart low on oil when they rolled in then they over fill it with the worlds crappiest oil. Owner drives away with an engine oil issue they were not aware of. Congratulating themselves they waited 2 hours and had a donut and had the mother ship check the car thereby eliminating any personal responsibility ever to whats going on under the hood.
    Its a sweet sweet feeling how good I take care of my car lol.

    Some people have never opened there hood ever.
    Many post on here about an underhood noise problem and never even open the hood to check themselves. or they have had a check engine light on for a while or a RTOD and keep driving. if I see that I pull over. Those folks are guaranteed to blow there car up.

    You do not get an ASE mechanic changing oil at the dealer. You get a minimum wage monkey who is trained to remove dump bolt and filter dump oil and then hold the oil pump trigger. Rarely do they speak English in my observation.
    If anyone who has there car dealer serviced doesn't believe me next time you get a change at the dealer let them take your car. 20 mins later go around the back of the building and find your car and see whats going on and talk to the oil change guy. The back of the building is where all the nasty oil vats are.

    Always after an oil change let the car sit for a while and check the oil.

    Its real simple to prevent #2 piston from taking a leave of absence in the block by routine oil level check.
    Make sure the car has been off overnight as there is alot of oil in the vvt/vvt filter galley and takes a while to drain back for accurate measurement.
     
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  11. sam spade 2

    sam spade 2 Senior Member

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    The amount is important in this discussion.

    If the oil usage gradually increased a tiny bit every (pick a number, maybe 30,000 miles) and seems to increase after 100K miles........not a real "problem" as that is normal for almost all engines. And the fact that some don't seem to use any (or very little) does not necessarily mean that they all should do that.

    OTOH, if there is a sudden and significant increase in the usage, then that might be worth worrying about.
     
  12. padroo

    padroo Senior Member

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    The most important thing you can do for your car is maintain fluid levels and scheduled changing of fluids, every thing else comes second.
     
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  13. T1 Terry

    T1 Terry Junior Member

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    The mileage is in my signature line, the ex taxi has 720,000km on the clock and the PHEV has 263,000km on the clock. The ex taxi had a strange noise when accelerating hard and after one long drive where a fair bit of high speed highway driving was involved that noise started to occur with anything more than light throttle applied. The noise did sound like a timing chain the the taxi fleet owner I bought the vehicle from told me it had a timing chain problem. It turned out to be a blocked cat, the noise was the exhaust flange bouncing back and forth onto the manifold because the spring loaded exhaust flange was moving away under pressure and returning with a metallic noise when the pressure was released. The blocked fuel filter had caused a lean run condition increasing the cyl and exhaust manifold temperature causing the carbon to dislodge and block the cat.
    Someone on another thread pointed out that the Australian Prius has a different fuel tank and filter set up to the US model and the US model has the filter inside the fuel tank and some form of bladder arrangement. The Australian model the filter in mounted along the fuel line and easy to change.
    As far as engine oil flush goes, you are quite right bout goo quality oil being changed regularly will negate the need for engine oil flush to be used ..... unless the engine has quite a few miles on the clock. Then, the oil flush will help remove the gums that collect inside the various oil passages and free the oil rings to again do their oil scrapping job. It is quite an eye opener to see just what comes out after a does of quality oil flushing agent is used.

    T1 Terry
     
  14. webbster1216

    webbster1216 Junior Member

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    My 07 has a little over 245k on it and burns maybe half a quart every 500-1k miles. I experimented going up to a 10w30 to see if that resolved it, but still remained constant. Right now Im running M1 0w40 european formula since I had a surplus of it. My CEL is on due to the cat sensor but never really investigated it fully... My mechanic is the master prius tech at the dealer by my house and he claimed certain years of the gen 2 (2007 being one of them) consume more oil than others. I mainly use it for highway driving, so I figured thats probably a major factor in my case.
     
  15. T1 Terry

    T1 Terry Junior Member

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    Back when I had my automotive workshop, we had mixed results from vehicles using Mobil 1 synthetic (I'm guess that is what you are referring to as M1). Some had very high mileage and no issues but these vehicles did have their oil changed every 5,000kms so not sure if that had anything to do with it, others used the advertised extended mile capability to justify the added cost and only did 20,000km oil changes. Of these extended distance oil change group some started to experience increased oil consumption after roughly 100,000kms. Some came good after a few services using Wynn's oil flush in the old oil for a few days before the service but others didn't see much improvement and promptly traded the vehicle in on a new vehicle.
    Now, I really don't know if the fact there was only 5,000km between oil changes for the first group that it wasn't really long enough to register they were using more oil than previously or if the frequent oil changes kept the oil rings free from gum and junk. Some of the frequent oil change group really drove their cars hard so ????

    T1 Terry
     
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