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Using lots of oil, throwing cat code, questions...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Max Finch, Jun 11, 2018.

  1. Max Finch

    Max Finch Active Member

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    I’ve put approximately 72,000 miles on my 08 touring since I’ve owned the past year and a half. The car is currently sitting at 156,680 miles.

    Driving home from a road trip last night, got my first ever engine code with it. P0420 catalytic converter.

    I cleared it using my OBD II device, ran fine back home and during today for about another 400 miles before throwing the code again.

    Now the car burns almost all the oil between my 3,000 mile oil changes. My first concerns where valve cover gasket and PCV valve. I changed spark plugs at 120k, but left the PCV because I hadn’t read up on changing that while changing plugs.

    I pulled the coil packs out and see absolutely no signs of oil. Would this mean my valve cover gaskets are fine?

    Should I suspect PCV valve?

    156k miles, bad gas mileage (35 mpg avg with roof rack, used to get more than that)

    Lower than normal power. Used to pick up faster than current, also hardly reaches 100 mph (don’t ask me how I know that lol)

    Or should I suspect bad o2 sensor, or just listen to the code reader and suspect a bad Catalytic converter? I feel the light should’ve returned much quicker if the cat was bad.
     
    #1 Max Finch, Jun 11, 2018
  2. JC91006

    JC91006 Senior Member

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    Bad engine, bad cat. need to replace both
     
    #2 JC91006, Jun 11, 2018
  3. Max Finch

    Max Finch Active Member

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    Not seeing oil in spark plug wells but am seeing it underneath the valve cover where the fuel rail is. Some small pools, perhaps the gasket is bad?
     
    #3 Max Finch, Jun 11, 2018
  4. JC91006

    JC91006 Senior Member

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    Burning oil to contaminate cat, using all its oil by 3000 miles is quite a bit. Also loss of power.

    You can replace the cat first but the engine replacement won't be too far behind
     
    #4 JC91006, Jun 11, 2018
    Mendel Leisk likes this.
  5. Max Finch

    Max Finch Active Member

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    So the question is:

    If I live in Oregon, do I get an aftermarket, should I buy a used from lower mileage wrecked, or because the hybrid system is unique am I forced to go with OEM?

    Additionally, I’m still wondering if a PCV valve and valve cover gaskets would be the cause of my oil loss. Though I haven’t seen oil in the spark plug wells I did see pools on the outside near the fuel rail. I haven’t actually pulled the plugs out, the spark plug socket I have on hand couldn’t reach it, so I haven’t been able to check for white tips indicating that I’m burning oil, which from what I understood is more serious than a leaky valve cover gasket
     
    #5 Max Finch, Jun 11, 2018
  6. edthefox5

    edthefox5 Senior Member

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    White tips do not indicate burning oil they indicate lean or running fine.

    Losing 3.5 quarts is a lot of oil that would leave a little oil on the ground under the car if it was leaking that much.

    Your burning s tremendous amount of oil most likely because someone ran the engine so low on oil once it turned on the master caution light on the dash indicating 0 oil pressure. Toughest little engine ever but will not tolerate no oil and usually burns the oil ring on the pistons. Don’t waste anymore time on that engine it’s toast.

    Buy a used hopefully low mileage motor. eBay has lots.
     
    #6 edthefox5, Jun 13, 2018
    Max Finch likes this.
  7. fotomoto

    fotomoto Senior Member

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    You're burning oil not losing it through leaks (well some is leaking out). Replacing the valve cover gasket should stop the small leaks as the outside edges are the usual fail points and make your engine smell better once the old oil is cleaned off. There's no easy/cheap way of solving the usage issue other than to stay on top of it by frequent checks & fills and deal with the downstream issues (o2 sensors, clogged cats). If you've never changed the PCV valve, it should be changed.

    You'll need to check your local laws on replacing the cats. If you can use an aftermarket universal unit, great but if you have to use OEM Toyota, they are very expensive so finding a low miles junk yard cat would be the way to go.
     
    #7 fotomoto, Jun 13, 2018
    Max Finch likes this.
  8. JC91006

    JC91006 Senior Member

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    There are 3 things that will be fairly costly in your near future. You can continue driving with the current engine, just make sure you check oil levels often.

    1. Catalytic converter
    2. Engine
    3. Hv battery

    So driving 50k a year is pretty significant, you might want to look into another car or prepare your wallet for a cleanout soon
     
    #8 JC91006, Jun 13, 2018
    Max Finch and Raytheeagle like this.
  9. Max Finch

    Max Finch Active Member

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    Ah maybe I’m not burning all my oil then. I’m doing about 2 qts every 3k miles. I’m the second owner of the vehicle, the last owners had it up to 84k miles, they were an older couple and had maintained this vehicle through my local dealership.

    I bought this in 2016 and currently have 157k miles. I haven’t seen that light come on, I started really checking the oil at around 130k miles. When I bought the car it wasn’t loosing any oil.




    I live in Oregon and have a aftermarket cat coming in the mail Wednesday.

    I’m changing the PCV valve this Saturday and since everything will be ready I’ll change the valve cover gaskets as well.



    I live in Oregon and just dished out $180 for a new Catalytic convertor. I imagine that’s where all my performance problems are. The engine is loosing about 2 qts every 3k miles. The traction battery still seems to be going strong, I’ve done all the not so accurate tests on Prius Chat, not seeing rapid drain. Of course the only way to be sure is to plug it into a tech stream right? The plan is to own the car through college and purchase something more in my alley like a 4Runner or Tacoma. I’ve got a year left of school.
     
    #9 Max Finch, Jun 14, 2018
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