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Thread: Possible head gasket oil leak on Gen VI 502?

  1. #1

    Possible head gasket oil leak on Gen VI 502?

    New engine build. Gen VI 502 with Edelbrock Performer RPM heads. Block was checked @ machine shop for anomalies such as warped deck while it was being honed. Checked out OK. Heads are new. Used SCE head gaskets, ARP head bolts. Affixed the heads to block with ARP recommended torque and used the thread sealant/lube included with the bolts.

    Engine was fired up for the first time last week. Oil is leaking from the head gasket. I know this sounds weird, but Iíve triple checked all the usual suspects for leakage, and it is indeed the head gasket, and not a telegraphed leak for somewhere else. Itís leaking from both sides of the block in approximately the same area. Beneath the rear most spark plug (Numbers 7 and 8 ).

    Iíve attached a pic of the leak issue. Itís of cylinder #8. Notice the #11 bolt itself is shinny, indicating maybe the oil was seeping up from the deck. Note the boss in the block below the bolt. That was quite wet with oil, and I cleaned it. The gasket seems shinny and saturated. This scenario is not the case on the number 7 cylinder. The bolt is dry, but a similar boss in the block right beneath it was wet with oil, and dripped from that boss onto the header. In the pic, the header gasket has some blow-by that may be responsible for the wetness on the bolt. The brownish trail is not coming from the spark plug hole.

    I have 3 thoughts on what might have happened and what I would need to do to fix:

    1. Wrong head gaskets. Iím checking my receipts to double-check I got the right gaskets. If I got the wrong ones, Iíll get the correct ones. Question: If they were the wrong gaskets, would some other issues have occurred as well? (i.e. overheating?)
    2. Since the leaks are from the same basic location on both sides of the block, maybe that particular bolt hole (bolt #11 in the Edelbrock torque sequence chart) in the block is not as deep as it should be and is bottoming out? I suppose I could add a washer to fix that.
    3. Re-torque the heads. With maybe 10 minutes of running time so far, I think this would be unusual, but this is the first time Iíve run aluminum heads, so maybe not? (I used a Snap-On torque wrench to torque the bolts when installing the heads. Plus, the leak seems to have begun right away)

    Thatís all I can think of. Love to hear your suggestions. Thanks.

  2. #2
    Senior Member RACING JUNKIE TheYellaBrick's Avatar
    Join Date
    Mar 2008
    Emmett, Idaho
    NOTE to diagnostic technicians:

    The photo looks at first to be a double exposure. The firewall is polished or VERY SHINEY paint(left side of pic). I thought my eyes were going kookoo !

    :shock: ops: ops: ops: ops: ops:
    to those who

    God Bless our folks in uniform
    "We the People, have your backs"

  3. #3

    You're right

    Yeah, when you click on the thumbnailed pic, it comes up oriented to the left. What you're seeing is the mirror image of the engine in the chrome firewall plate. Scroll right to see the area in question.

  4. #4
    Senior Member RACING JUNKIE
    Join Date
    Jan 2012
    Dunno. Appears to be a bolt in an oil galley and the pressure is daylighting at the bolt head, but I dunno that there's a galley at the bottom ot that particular set of bolts.

    Either that or you have the wrong head gasket, but again, I can't think of a common galley or passage those bolts enter or are really close to.

    I'd be removing the heads and looking at the tracks . . because it won't heal itself . .

  5. #5


    Thanks for the replies. I did decide to remove the heads. Things do not look good. So, the engine is coming back out for tear down and inspection to find out what's going on.

  6. Racing Junk

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