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2008 Prius burning oil and need options...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by CU David, Mar 14, 2017.

  1. 05PreeUs

    05PreeUs Senior Member

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    Oil "thickness" is RESISTANCE to flow.

    We can think of the second number, the "30" in 5W-30, as the viscosity equivalent at 100*C. This means that the oil has the same kinematic viscosity at 100*C as the standard for "30wt" oil. Due to differences is base stocks, some variation will occur. 5w-30 is still 5wt oil at 100*C, but has viscosity improvers "VIs" (these provide ZERO lubrication) so the oil acts thicker at elevated temperatures. The greater the difference between the two numbers in your oil, the more VI in each quart.

    Oil is the ONLY thing in a quart of oil that provides lubrication protection for an engine, period. If you have a 1qt mason jar filled with 5wt oil and you want it to act like 30wt at 100*C, you MUST introduce additives. As you do so, some of that 1qt will need to be removed to make room for these other things; picture adding three or four large ice cubes to your full mason jar w/o removing any liquid first :(

    Almost all normal wear (not due to maintenance lapses or overheating) occurs at START-UP, therefore the most critical time for the lubrication system is then. This is why FLOW if the most important thing to long engine life. As a secondary benefit, greater oil flow thru and engine keeps them cleaner by transporting particles more efficiently and provides improved cooling. Yes, one of the top 3 jobs of oil is to provide cooling.

    Toyota DOES NOT approve anything but 5W-30, except as a temporary measure, they advise to replace it at the next oil change if you use even 10w-30.
    upload_2017-4-2_10-12-33.png
     
  2. valde3

    valde3 Senior Member

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    Yes. But because of how oil pump works it’s not best to have the thinnest oil as flow doesn’t increase that much when viscosity goes down. Other vise thinnest oil would always be better. That’s why there’s the recommended oil thickness.
    And also why it might be better to use a bit thicker oil on worn engine as it will get the oil pressure closer to original value. Even as it will of course reduce the amount of flow a bit (depending on wear might reduce it to around the original value).

    Only true with conventional oils. Synthetic base oil already has better viscosity index.

    On North-American market yes. But for the same engine in Europe and in Australia (probably in other places as well) they do give the chart that I posted link to on my previous post.
     
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  3. 05PreeUs

    05PreeUs Senior Member

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    The Toyota engineers have spend thousands of hours and millions of dollars to develop their recommendations, no one else has even come close.

    Actually, quality pure synthetics use NO VIs, because there is no need with an engineered molecule.

    You cannot compare markets. The oil specification are NOT universal, what the SAE/API use a guidelines in the USA do not directly correlate to the EU and Pacific rim standards. There are often (actually usually) minor yet important testing and specification differences between them.
     
  4. valde3

    valde3 Senior Member

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    I didn’t mean that I would know some oil thickness that’s better than what Toyota suggests. Of course they do know what’s best for their car. But recommendations are still based one new or slightly used engine. Not for old worn engine that you just still want to get some use out of.

    That’s my point. All that you were talking about was for conventional oils and not about synthetic. So it’s all irrelevant if you’re running synthetic oil.

    Yes but your claim that engine would through a rod if you increase oil viscosity is still pretty much proofed wrong by Toyota actually recommending that higher viscosity for some climates.
     
  5. Kevin_Denver

    Kevin_Denver Active Member

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    I remember how irresponsible I was at 18. I agree that for the majority of college students, a low maintenance car is best. With all the other life changes one has to deal with it's easy to forget about a car and starve it of oil.

    Best option for the time being is thicker oil, climate allowing (see your owner's manual for a temperature guide). As you're already using high mileage oil, I'd stick to it, just go a bit thicker, probably a 10W-40. You'll take a percent or two hit in fuel economy but should notice some reduction in oil use. Even a 15W-50 is safe, you just may have problems starting in cold weather (as shown in owner's manual)

    Your oil use will likely get worse over the age of the car, but it wouldn't surprise me if there's another 50k of engine life left either. I personally think an engine replacement/rebuild isn't yet needed (I'd wait until it was over a quart per 1000 miles ). I also wouldn't bother with the cost of synthetic oil if I was just going to burn it up (just use normal high mileage oil). With the Prius' hot water insulator that keeps the engine warm much longer than other cars, synthetic oil has less benefit than other cars anyways.
     
  6. Sam Spade

    Sam Spade Senior Member

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    No you don't. The statement you made was about "quality control" in EVERY engine shop in the country (world).
    There is no way you can know that.
    You may think you have enough evidence to draw that conclusion .......but it still is just a somewhat educated guess.
    Of course, you think it is gospel.......because YOU came up with it.

    BYE.
     
  7. SFO

    SFO Senior Member

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    True, the EU and Asian markets DO require higher standards for certain applications. From my minimal research (read: not an expert), the specifications for ACEA C1 and JASO DL-1 have some of the lowest required SAPS levels (among other stringent requirements), yet still exceed other oil standards for many important criteria. Even the newest API FA-4 (PC-11b) spec has a higher SAPS level (or unchanged from previous).

    Sure, using an oil with lower SAPS content probably won't matter for those living outside of the California/New York markets (and some countries maybe) where catalytic convertors are plentiful/affordable, but If anyone is truly concerned with an engine burning oil, having ring/carbon build up, general wear and or ash/metal deposits on the catalytic convertor then they might want to know about the engine oil they're using or choosing not to use.

    Many might be interested in finding out more information regarding the minor testing and specification differences between the international guidelines if you (or anyone) know of resources. There are many links for either or (some I've already found), but nothing that makes it all that easy to access the bigger engine oil specifications picture.

    Question: Does anyone know of a North American oil supplier that offers ACEA C1 or JASO DL-1 compatible oils at an affordable price?
     
  8. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    +1
    Especially in Caly.
    Sooner or later an oil burner is going to fod out the catalytic converter.
    In most states, this is a < $200 reapir.
    In one state......it's much much higher.

    Good Luck.
     
  9. Mavi

    Mavi Active Member

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    UPDATE: Now the engine is technically at 135k miles (swapped in at 85k miles) and does consume a bit of oil.. enough to notice after 5000 miles. Engine was from a 2008. For what it's worth i had paid 1200 for 50k of trouble free miles which was worth it for me, and the engine it replaced has 185k miles and ate an insane amount of oil, but with this now in mind, most likely a complete rebuild of the engine would be the best solution if you plan on keeping the car for 300k+ miles like I will. (Car is currently at 225k.)
     
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  10. uart

    uart Senior Member

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    Thanks for the update Mavi, it sounds like you got a good deal.

    Don't worry about small amounts of oil usage, but do check it regularly. Most people only have problems because they don't check it or top off, and then a small amount of oil consumption suddenly turns into a big problem. Maybe start doing a top off at about 2500 to 3000 miles, it takes about $3 worth of oil and about 3 minutes of your time for a lot of piece of mind. That engine will probably go another 100k + miles as long as you keep the oil up to it. :)