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Thread: V8 valley cover oil leak

  1. #1

    V8 valley cover oil leak

    Hi all,

    If oil is sitting all over the top of the valley cover gasket, what would be the common causes?

    I was thinking it would be the end rubbers in the valley but they are under the gasket so not sure how the oil would get out and then up and over it.

    The leak seems to accumulate on top of the valley gasket and then runs down the front and coats the RHS of the motor and the front diff.

    I replaced the valley cover gasket and the end rubbers about 2 years ago or more. This leak has been there for a few months at least though. Been ignoring it but it is getting worse.

    Any ideas where the oil is coming from?

    Just to add it is a 3.9 V8 serpentine belt motor in a 1994 Discovery.

  2. #2
    Join Date
    Jan 1970
    Location
    Somewhere else, QLD
    Posts
    1,864
    Give the engine a clean and take the flame trap/pcv filter off. That will at least confirm or eliminate the standard version of valley cover oil leak. ( Flame trap gums up and blowby pressurizes the crankcase and blows oil mist out everywhere it can).

    Whether or not another valley cover/gasket is needed is unknown.

    Of course it could be a leaking rocker cover gasket as well. If you can track the oil leak, it will give you a better idea on what may be a bigger problem.

  3. #3
    Join Date
    Aug 2006
    Location
    Kingston, Tassie, OZ.
    Posts
    12,474
    Quite possibly the rocker cover gaskets, if it still has the rubber type gaskets, then even if they are tight they can still leak like a seive. A bit of a pain to change but easier than the valley etc.

    JC
    The Isuzu 110. Solid and as dependable as a rock.
    The Range Rover L322. Good enough for Her Majesty- good enough for me.

  4. #4
    Thanks guys. I figure it is the rocker cover gaskets too. Was just putting it out there to see if there was something I hadn't thought of.

    I replaced both rocker cover gaskets when I did the valley etc last time. I used the rubber ones.

    JC it is interesting to hear you say that the rubber ones are no good as I used them last time due to hearing that they were the way to go.
    I had changed the driver's side gasket once earlier (with rubber one) and when I did them again with the other work it had split along its length and was leaking so I am already dubious of their all round goodness.
    What do you use/recommend?

    I have cleaned the PCV steel wool/mesh thing before. Will clean it again when I redo the tappet cover gaskets. Didn't think of that pressurising the joints so thanks for that.

    Thanks

  5. #5
    Join Date
    Aug 2006
    Location
    Kingston, Tassie, OZ.
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    12,474
    Quote Originally Posted by Utemad View Post
    Thanks guys. I figure it is the rocker cover gaskets too. Was just putting it out there to see if there was something I hadn't thought of.

    I replaced both rocker cover gaskets when I did the valley etc last time. I used the rubber ones.

    JC it is interesting to hear you say that the rubber ones are no good as I used them last time due to hearing that they were the way to go.
    I had changed the driver's side gasket once earlier (with rubber one) and when I did them again with the other work it had split along its length and was leaking so I am already dubious of their all round goodness.
    What do you use/recommend?

    I have cleaned the PCV steel wool/mesh thing before. Will clean it again when I redo the tappet cover gaskets. Didn't think of that pressurising the joints so thanks for that.

    Thanks

    Sorry, I meant they ARE the best ones (The ones with the metal inserts in the bolt holes, as per OEM) until they go hard, and then due to the metal inserts you can't tighten them up any further. These are all I use now.

    JC
    The Isuzu 110. Solid and as dependable as a rock.
    The Range Rover L322. Good enough for Her Majesty- good enough for me.

  6. #6
    Thanks JC. I did use the rubber ones with the metal bolt hole bits.

    Do you silicone them on to the head?
    I'm thinking of doing so this time around.

  7. #7
    Join Date
    Aug 2006
    Location
    Kingston, Tassie, OZ.
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    12,474
    Quote Originally Posted by Utemad View Post
    Thanks JC. I did use the rubber ones with the metal bolt hole bits.

    Do you silicone them on to the head?
    I'm thinking of doing so this time around.
    No sealant required, I find I just sit them on the top of the head and jiggle the rocker cover around until the holes line up, make sure the edges are outside the cover and bolt em down tight

    JC
    The Isuzu 110. Solid and as dependable as a rock.
    The Range Rover L322. Good enough for Her Majesty- good enough for me.

  8. #8
    Join Date
    Jan 1970
    Location
    Western Sydney
    Posts
    25,988
    Check the rocker cover bolts. They loosen and allow the gaskets to leak. The bolts are standard 12-point heads but trying to find a 12-point socket in 1/4" drive is a little difficult. I borrow one from my local LR workshop.
    Ron B.
    VK2OTC

    2004 L322 Range Rover Vogue 4.4 V8 Auto
    Yamaha XJR1300
    Previous: 1983, 1986 RRC; 1995, 1996 P38A; 1995 Disco1; 1984 V8 County 110; Series IIA



    RIP Bucko - Riding on Forever

  9. #9
    Alrighty then. Just finished slashing the back of my right arm on some zip ties that weren't properly trimmed. Oh what fun.

    While I was doing that I removed all the 12 point bolts and replaced them with allen key bolts. Socket head screws I think they called them. The same type that are holding your plenum cover lid on but smaller.
    Those factory bolts annoyed me once too often.
    They are 1/4in UNC. One lot were just under 1in long and the other lot were 1 1/2in long.
    I glued washers under the heads with one of the Loctite glues.
    Didn't remove the tappet cover gaskets as they seemed pliable going by the protruding edge/lip and they are only a couple of years old so I hope they are still ok.

    I also cleaned the steel sponge mesh in the PCV/fire trap thing again. It was thick with oil in the mesh (not gungy but fresh stuff) so I don't know if it is meant to be like that or if it was clogged. The hose that came off it that goes to the air intake was clean. Either way the mesh is clean now.

    Ron I have the 12 point socket in 5/16 3/8 drive. 1/4in would be better but wasn't available at the shop when I bought it. Quite happy that I no longer need it for this job though.

  10. #10
    Join Date
    Feb 2008
    Location
    Northern Windowlickersville WA
    Posts
    3,348
    Quote Originally Posted by p38arover View Post
    Check the rocker cover bolts. They loosen and allow the gaskets to leak. The bolts are standard 12-point heads but trying to find a 12-point socket in 1/4" drive is a little difficult. I borrow one from my local LR workshop.
    I got an 8mm 3/8 drive 12 pt and it fits fine in the cover bolt recess. If it is a bit tight, just "finish" it off on a grinder a little bit.
    Either that or just look in a Kingchrome catalogue and order one.

    Cheers

    Andrew

    Bonnie - MY03 D2a TD5 Auto (One Bourbon)
    Clyde - MY93 RRC 3.9 Classic (One Scotch)
    Arfa - S2a 109" custom trailer (One Beer)
    Earl - The "Duc" 2009 Ducati Sport Classic (chuck in a Lambrusco)

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