Mystery oil leak. I'm lost. Please help.

LEGACY_GN

Active Member
#1
New stroker motor and ever since I have had a pretty big leak dripping off the passenger side header flange which then drips on to the header and all over the starter. You can clearly see wet oil on the bottom of the header flange right by the middle cylinder. The valve cover is bone dry all the way around. The car does not smoke under boost and the oil is clean, however it does have intermittent blue smoke from exhaust at idle which I attributed to a bad turbo seal. Breather at front of valve cover is also dry. Could the head gasket be leaking oil? Car runs great, no smoke under boost. Coolant is also clean.
 
#2
New stroker motor and ever since I have had a pretty big leak dripping off the passenger side header flange which then drips on to the header and all over the starter. You can clearly see wet oil on the bottom of the header flange right by the middle cylinder. The valve cover is bone dry all the way around. The car does not smoke under boost and the oil is clean, however it does have intermittent blue smoke from exhaust at idle which I attributed to a bad turbo seal. Breather at front of valve cover is also dry. Could the head gasket be leaking oil? Car runs great, no smoke under boost. Coolant is also clean.
If you have aluminum heads, they probably drilled your header bolt hole too deep and it is weeping oil from under the valve cover, pull the bolt or stud and put some sealant on it, worked for me.
 

LEGACY_GN

Active Member
#3
Champion Iron heads from early 90's. I had a fresh valve job done on them for the build but I don't think the machine shop did anything to the bolt holes.
 
#4
My car has same oil leak. I believe it's coming from corner of valve cover, but haven't really looked for it because my transmission went out. Pull valve cover and look at gasket.


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larry33kc

Well-Known Member
#12
I have the same exact thing going on with my setup but it's the driver side. Valve cover is bone dry, valve cover breather dry. Just a drip every so often and I can't figure it out either.
 

LEGACY_GN

Active Member
#13
Not the turbo oil return. Just checked. Also Larry, through researching this I found that if it's on the drivers side it's often blowing out of the oil dipstick under boost. Several I seen had that.
 

larry33kc

Well-Known Member
#14
Mine will drip at idle also. My dip stick tube is dry. I see there is a 1/8pipe plug there where it is coming from but I can't see it coming from it.
 

LEGACY_GN

Active Member
#15
Update 5 years later. It was oil blowing out of the PVC seal in the intake. It would fill up the top of the intake at the back and then drain down passenger side head where it meets the block and that's how it was ending up on bottom of header flange. Replaced grommet and no more oil.
 

berserker6

Assistant to the regional manager
#16
Yes! Kudos for coming back after so many years and posting what you found. Hate when a thread just stops with no resolution.
 

LEGACY_GN

Active Member
#18
It's no mystery Buick engines leak oil. :eek:

Neal
There was never a mystery about whether or not Buicks leak oil. The mystery was the location of the leak. It still leaks, at this moment from the transmission at the speedometer socket. But that's not a mystery. And the turbo leaks too, just not onto the ground.
 

750H.P.V6

Old confused member
#19
Sounds like old car stuff to me. The drips and leaks can drive you crazy. If there not that bad don't let it keep you from enjoying your passion. :cool:

Neal