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Sparkplugs & Borescopes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by edthefox5, May 8, 2018.

  1. edthefox5

    edthefox5 Senior Member

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    Just changed my plugs & cops & pcv valve. Had intentions of changing the valve cover gasket also but it looked harder than I thought so didn't get to it. I also bore scoped the cylinders. There's pics:

    Bought new 07. Has 120000 miles on the car. OCI with OEM filter @5000 miles with either M1 or Redline 5-30.

    Sparkplugs: I got lucky they were not tight at all. They all came out uniformly easy. Felt like 15-20 lbs. 5/8 sparkplug socket. Using a flexible socket wrench made it 100% easier. I highly recommend buying a 3/8 flex socket wrench. I also replaced the cops while I was in there. Pics of the plugs look perfect.
    I have been buying new cops one every few years in anticipation of this.The car with new cops and plugs ran noticeably better much better pickup. The old cops ran fine. And look fine.
    Before I pulled the plugs I used my borescope to check for oil or debris in the sparkplug well. Found cylinder well #4 had oil in it from weeping valve cover gasket. I suspected weepage with this type of v cover. I checked the valve cover bolts and they were all uniformly not tight not really loose but you could do a one hand snug up with a socket wrench.

    Ran out of time to pull cover. I have the gasket. Next weekend. Interested to see how my oil oci looks in the valve area. I will post pics.

    PCV Valve: Its a pain to get too as the wire loom is in the way. You have to unbolt all its hold downs and lift it out of the way. I used a 19 MM box end wrench. The pcv valve is on there very very tight. I gave the wrench one good whack with a 5 lb hammer and the valve broke free. It is really socked on there. Best to find a 1 3/4 inch id pipe as a breaker bar slip over box wrench it would have made it a snap. Slip the pipe over the wrench end. The pcv valve looked good for 120K miles and was operating.
    The pcv hoses were a mess. There's 2 hoses from the throttle body to the valve cover. One is a breather the other is the pcv hose. Both had cracked & loose ends at the throttle body and must be replaced. I replaced one with a hose from a parts store the other I cut back the cracked portion of the hose. The breather hose had different ends on it one end is fat the other smaller. Im going to buy the oem hose for that one. Put clamps on all 4 ends.

    Piston Borescope: While I had the plugs out I scoped all the cylinders. They looked pretty good. 1 & 3 had uniform light soot buildup very light. 2 & 4 had no real bad soot buildup just very light soot speckled deposits and a weird circle of deposits on each piston. Both cylinders had this unique circular splatter on an otherwise pretty clean piston. You can see the circle in the pictures. Very odd.
    I attribute it to the atkinson cycle where the exhaust i believe is delayed closely.

    So on a tune up those pcv hoses should be looked at. And my car is very well cared for and I have a valve cover gasket leak so that makes me think its pretty common on this car. Something to check. It will cause misfires. And if cover gasket not replaced you'll be right back in there. Cover is a pain the bulkhead should be pulled to get to it.
     

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    #1 edthefox5, May 8, 2018
    Last edited: May 8, 2018
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  2. Mendel Leisk

    Mendel Leisk Senior Member

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    This is the one where an open-end wrench can end up busting a hole through your valve cover?
     
    #2 Mendel Leisk, May 8, 2018
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  3. edthefox5

    edthefox5 Senior Member

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    yes

    Its in a tight space and really socked on and no place for a good throw so you should use the correct tool or you may bugger it up. Quality 19MM box end works. Slip on breaker bar pipe is better.
     
    #3 edthefox5, May 8, 2018
    Last edited: May 8, 2018
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  4. edthefox5

    edthefox5 Senior Member

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    more pics
     

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    #4 edthefox5, May 8, 2018
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  5. edthefox5

    edthefox5 Senior Member

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    more pics
     

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    #5 edthefox5, May 8, 2018
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  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you are planning to remove the valve cover anyway, you potentially could remove the PCV valve after the cover is off the engine. Then there is no problem using a deep socket and breaker bar without having to work around the engine wiring harness etc.

    When installing the new valve cover gasket, don't forget the Toyota black FIPG or equivalent, which needs to be placed at two spots where the engine front cover meets the cylinder head.
     
    #6 Patrick Wong, May 8, 2018
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  7. SFO

    SFO Senior Member

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    Though barely visible, I like how you left the 'throttle body hot coolant bypass' out of the picture :sneaky:
     
    #7 SFO, May 8, 2018
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  8. edthefox5

    edthefox5 Senior Member

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    Hey Pat-
    I replaced the pcv valve before I discovered the leaking valve cover gasket or I would have gone that way. So did it backwards a little.
    If I had known the cover was leaking in the well I would have waited. I do not see it leaking on its outside edge so was hoping I was ok.


    And thank you for the fpig selant. Mendel was nice enough to list a gasket diagram and part number and fpig points in a previous post.

    Looks like the cowl & bulkhead have to come out. I'm going to buy a new seal that runs along the top edge of the cowl but do you recommend I buy a new cowl seal I see in the parts diagram? I think its the bulkhead gasket. Not sure never been in there before.
     
    #8 edthefox5, May 8, 2018
  9. edthefox5

    edthefox5 Senior Member

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    Never got much response mentioning that and its pushed aside so it did not make the picture. Lets see if anyone else notices it and cant figure out why?
     
    #9 edthefox5, May 8, 2018
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, it is very helpful to remove the cowl tray and really not difficult to do. The very long rubber seal that runs along the edge of the cowl can be reused. It is held onto the metal tray with plastic pins. Use long nose pliers to squeeze each pin so that you can remove the pin from the metal cowl without causing damage to the pin.

    If you are concerned about the small seal that is between the two black plastic cowl pieces, you can use some of the black FIPG to replace that seal.

    You likely will have to replace the two plastic pins that are located at the ends of the black plastic cowl pieces, as those pins will deteriorate due to age and exposure to sunlight.
     
    #10 Patrick Wong, May 8, 2018
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  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Some conduit pins you can release with cowl half off, if it's similar to 3rd gen. I've found some easy enough while the cowl's still on, but if access is hard, having the cowl half off and flipped over might make it easier; and you can see better what you're doing.
     
    #11 Mendel Leisk, May 8, 2018
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  12. Stimp

    Stimp Member

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    Getting to know my used Prius today I inspected the spark plugs. A lot of life left in them, clearly were changed at an appropriate interval - at 190k now, def will last to 240k. A couple of concurring observations:

    1. I also tightened the accessible valve cover bolts and nuts as a result of point #2, they were not tight and match your description.

    2. Found some oil residue in the #2 spark plug well. Not "pooled" around the plug like your picture, but there nonetheless. The COP boot protected the upper part of the plug very well. Hopefully point #1 will help this. Something to consider for anyone with a gen 2, since it's probably a common problem as you state.
     
    #12 Stimp, May 14, 2018
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  13. edthefox5

    edthefox5 Senior Member

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    My bolts on the valve cover were very loose but Toyota likes all there bolts stupid tight so I surmise its just the rubber gasket smushing down over the years. Its a pretty thick rubber gasket. I got a cowl seal and clips on order so soon as I get that I'm going in.
    I have the v cover factory gasket already.
     
    #13 edthefox5, May 15, 2018
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