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Author Topic: Oil leak from cylinder stud??  (Read 1750 times)

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Offline sniper1

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Oil leak from cylinder stud??
« on: October 26, 2014, 06:44:10 PM »
My '75 550 has oil that is bubbling up from the cylinder stud (Number 11 in the picture). Somehow it is getting through the threads of the nut and spills over. Its not a lot of oil, but very annoying. It gets worse the higher I rev the engine and is worse when the engine is hot. I have torqued the head recently and all are in spec. Anyone ever have this problem? or have any thoughts on what to do to correct?
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Offline calj737

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Re: Oil leak from cylinder stud??
« Reply #1 on: October 26, 2014, 07:10:38 PM »
IIRC there should be an oring at that location. Has the head been removed recently or studs replaced? If all is stock, then for some reason it has probably failed.
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Offline bwaller

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Re: Oil leak from cylinder stud??
« Reply #2 on: October 26, 2014, 07:37:03 PM »
Here's a picture of what's probably happening, not the same stud but you get the idea. The head gasket is leaking compression close to that stud and a little oil bubbles up through the threads.


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Offline sniper1

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Re: Oil leak from cylinder stud??
« Reply #3 on: October 28, 2014, 11:43:51 AM »
The head has been removed about 3,000 miles ago. I can't remember there being O-rings around the cylinder studs there. I may have to crack it open again to take a look. Boy, I hate doing that.....
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Offline bwaller

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Re: Oil leak from cylinder stud??
« Reply #4 on: October 28, 2014, 07:58:51 PM »
There are no O-rings on the studs.
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Offline Duanob

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Re: Oil leak from cylinder stud??
« Reply #5 on: October 28, 2014, 08:35:59 PM »
Quote from: bwaller on October 28, 2014, 07:58:51 PM
There are no O-rings on the studs.

No but there is an o-ring between #11 and #10 that could be leaking. Usually it leaks out between the head and the jugs but you never know. Also don't count out that it could be a leaking puck dripping down on top of the stud/nut.
« Last Edit: October 28, 2014, 08:39:21 PM by Duanob »
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Offline bwaller

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Re: Oil leak from cylinder stud??
« Reply #6 on: October 29, 2014, 04:14:16 AM »
It'll take a compression leak to show bubbles through the threads.
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