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PCV Valve Replacement with Pictures

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Den49, Jun 25, 2015.

  1. Den49

    Den49 Member

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    I cleaned and replaced the original PCV valve on my 2010 Prius at 33,803 miles. Now at 73,792 miles I replaced the original with a new Toyota PCV valve. There have been a lot of questions about the location of the PCV valve and how difficult it is to replace so I took a few pictures.

    Below is a picture of the new PCV valve and the sawed off 22mm wrench I used.

    [​IMG]


    Below is a picture of the old and new PCV valves. I tried cleaning the old PCV valve again, but it seemed like it did not come entirely clean based on how it rattled compared to the new valve.

    [​IMG]


    Below is a picture from below and in front of the passenger side of the engine showing the wrench attached to the PCV valve.

    [​IMG]


    Below is a close-up picture of the old PCV valve with the hose and hose clamp attached.

    [​IMG]
     
    #1 Den49, Jun 25, 2015
    Last edited: Jun 25, 2015
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  2. bisco

    bisco cookie crumbler

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    why so often, bad gas?
     
  3. Former Member 68813

    Former Member 68813 Senior Member

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    i'll replace mine at the same time intake manifold is off for cleaning. 80,000-100,000 miles.
     
  4. SageBrush

    SageBrush Senior Member

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    I'll wait until 120k miles, and then replace
    • plugs
    • PCV
    • Struts
     
  5. dj2big

    dj2big Junior Member

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    Why would the manifold be off around that millage?

    S my Z987 ung talk
     
  6. Dark_matter_doesn't

    Dark_matter_doesn't Prius Tinkerer

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    How do you know the PCV valve needs to be replaced?
     
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  7. SageBrush

    SageBrush Senior Member

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    Is it really the passenger side of the engine ?
     
  8. Den49

    Den49 Member

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    Has nothing to do with gas.

    Huh???

    Look at the second picture in post #1.

    Coincidently, when I was at the Toyota dealer yesterday having the brake fluid flushed, they recommended that I replace the PCV valve based on the number of miles on the engine. I was pleased to tell them that I had done it myself. I didn't ask how much they charge for doing it, but the valve itself was only $7.41.
     
    #8 Den49, Jun 26, 2015
    Last edited by a moderator: Jun 27, 2015
  9. bisco

    bisco cookie crumbler

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    it must be bad something, around here, they seem to go 150k+ with no pcv problems. maybe the heat or type of driving?
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    This would be a proactive move to clean the EGR valve, valve plumbing, and the intake manifold passages associated with the EGR system. The EGR system builds up carbon deposits over time which will eventually trigger a fault code.
    The OP did not say that the PCV valve had failed. He replaced it as a preventive maintenance measure.
     
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  11. bisco

    bisco cookie crumbler

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    right, but for what reason?
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. During the normal operation of the gasoline engine, hydrocarbon gases resulting from gasoline combustion leak past the piston rings and enter the engine crankcase area. This is called "blow-by".
    2. These gases build up pressure in the crankcase area. In the old days, 1950s and earlier, the engine was just vented to the outside which resulted in unnecessary air pollution.
    3. Starting in the 1960s, the concept of "positive crankcase ventilation" was developed to take the HC fumes and direct them to the intake manifold so the engine would burn them as part of normal operations.
    4. The PCV valve regulates the flow of these gases to the intake manifold, based upon the amount of engine vacuum that is developed under various operating conditions.
    5. Since the PCV valve is exposed to the HC fumes, it develops HC deposits over time which will eventually inhibit proper valve operation. Hence the valve should be replaced periodically, I would say 100K miles is a good interval.
    6. The OP mentioned shaking the valve and listening to the resultant rattle as a means to judge the valve's condition. A new valve has a very metallic rattle while a used valve has a muffled rattle or in very bad cases, no rattle at all, due to the HC deposit buildup. Another way to judge the valve's condition is to blow air through it. The air should easily pass in one direction but not in the other direction.
    7. A plugged PCV valve may lead to engine oil seal leaks as the crankcase pressure builds up which forces engine oil past the crankshaft seals.
     
    #12 Patrick Wong, Jun 26, 2015
    Last edited: Jun 26, 2015
  13. bisco

    bisco cookie crumbler

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    thanks patrick, any ideas as to why some might clog earlier than others? iow, is there anything we can do to prevent it or delay it?
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I would say that those conditions leading to engine sludge buildup are probably the same conditions that would lead to the PCV valve clogging sooner vs. later. For example, very short trips are likely to develop sludge, where the engine oil does not have a chance to heat up and dissipate water vapor coming from condensation. That is why the engine oil needs to be changed at least annually, for vehicles that are seldom driven.
     
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  15. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe with muffled rattle it's still functional though?

    OTOH, I hate all mention of EGR and clogging, seems like that's the perineal elephant in the room. :(
     
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  16. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It is true that a valve with a muffled rattle is probably still working, but it is not as effective as a new valve in allowing the free flow of gases through it.
     
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  17. bisco

    bisco cookie crumbler

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    thanks again!(y)
     
  18. Den49

    Den49 Member

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    Patrick Wong - Thanks for explaining why one should be proactive in making sure the PCV valve works effectively. I'm sure that if I had posted the same information Bisco Et. Al. would still be needling me on the subject.

    Hey Bisco - How is it that with 29,324 posts and your seemingly 24/7 presence on PriusChat, you missed all the prior posts and information about the importance of the PCV valve? Maybe it is because you are preoccupied with making smart remarks and sticking it to people. My intention is to help others by posting useful information.
     
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  19. bisco

    bisco cookie crumbler

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    my apologies, if i hurt you in any way den, i was actually trying to learn something, not be sarcastic.

    the truth is, i don't usually bother with those threads, because i don't keep my cars that long.

    but when i saw your nice write up and pics, it made me curious to learn more.
     
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  20. Dark_matter_doesn't

    Dark_matter_doesn't Prius Tinkerer

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    RE third picture: I'm having orientation problems. Are you underneath the vehicle with the cover off, or on the top of the engine?