Thread: Oil Leaking From Intake Bolts

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if you just coat the threads with a sealer that stops the wicking i use ss bolts as well in many of my engine builds . the oil wicks up the threads with no sealer.... sbc has open holes not a blind thread holes only on the out side intake bolts of the heads on sbc and most all heads are open in the valley to hot oil coming off push rods as well as some are open to the push rod holes oil can lay in and some drain back from heads as you have ahot EX cross over as well on some heads and in time with out sealer fines its way out. sealer fills the root part of the thread s stopping it from ever getting up to the head of the bolt or washer . sealer will lube the threads very well and will seal it just fine . if blind hole then a very thin coat of oil . every one as there own way that works but ss or plane coated steel bolt with a zinc coating there is realy no need for anti seize less it in bad weather.salt.or SS steel on SS steel were the bolt and the head is the same metal make up you will have threads seize up

Why has no one suggested to check the PCV system? Check your PCV valve and the vent to make sure they are not plugged. Too much crankcase pressure will force oil out of bolt holes around oil pans, valve covers and intakes. If you a running at high RPM's most of the time you may need a vacu-pan system as the PCV system becomes ineffective at low vacuum conditions.

I know this is an old thread but it seemed the obvious was missed. This may help someone in the future.

Originally Posted by Two8tyThree

Why has no one suggested to check the PCV system? Check your PCV valve and the vent to make sure they are not plugged. Too much crankcase pressure will force oil out of bolt holes around oil pans, valve covers and intakes. If you a running at high RPM's most of the time you may need a vacu-pan system as the PCV system becomes ineffective at low vacuum conditions.

I know this is an old thread but it seemed the obvious was missed. This may help someone in the future.

i would say that you will push up the oil stick and vent from there and oil will blow out , vacu pans will not work on the street SO you will push oil out the seals front and rear you will vent thru the dip stick tube . oil filler cap may be wet to . before you pushing oil thru intake bolts so i would say nothing was missed ...? ... he did not say any thing about has oil pan or leaking oil as the engine will find away to vent it self .sounded more like a no thread sealer on intake bolts

Originally Posted by pat mccarthy

i would say that you will push up the oil stick and vent from there and oil will blow out , vacu pans will not work on the street SO you will push oil out the seals front and rear you will vent thru the dip stick tube . oil filler cap may be wet to . before you pushing oil thru intake bolts so i would say nothing was missed ...? ... he did not say any thing about has oil pan or leaking oil as the engine will find away to vent it self .sounded more like a no thread sealer on intake bolts

Agreed vacu pans are for high rpm low vacuum as stated. Just mentioned to cover all bases. Not street driven engines.
If the pcv is not working properly have seen the oil work through the threads of bolt holes. Once oil enters a bolt hole with a bolt in it there is a gap between the hole thread and the bolt thread unless it has sealer on it. Hydro static tension will hold the oil in the thread gap and any pressure ever so slight will work the oil up the thread.
If the pcv is working the negative pressure will draw the oil down the thread.
This was covered in a 2nd year class in mechanical engineering.

Originally Posted by Two8tyThree

Agreed vacu pans are for high rpm low vacuum as stated. Just mentioned to cover all bases. Not street driven engines.
If the pcv is not working properly have seen the oil work through the threads of bolt holes. Once oil enters a bolt hole with a bolt in it there is a gap between the hole thread and the bolt thread unless it has sealer on it. Hydro static tension will hold the oil in the thread gap and any pressure ever so slight will work the oil up the thread.
If the pcv is working the negative pressure will draw the oil down the thread.
This was covered in a 2nd year class in mechanical engineering.

well hot oil will find it way thru the root of the theads . BUT sealer stops this over 20+ years building engines . .you run a vac pan on the street and it will vent out the dip stick long before oil wicks out the intake bolts .thats not 2 year class thats many years building race. street EX and headers . as for the roping of oil out of a engine i do know abit about this as a guy thats used open beathers on very big bbcs and work on a crank case vent system on a 526 bbc in a air boat that was a leaning class i took about 13 years ago if neg psi pvc and working right your saying its going to wick out the head of the bolt on the intake ? it is sucking . if plug then pos psi and i would think the hot oil will rope the bolt threads and leak out intake BUT like said other spots will show first as a engine builder and engine machinist i see guys buy new valve cover with no spot for beathers or PCV and not use any PVC or breathers and have oil getting pushed out .but thread sealer stops it any way you want to look at this .but i am just a dumb mich hill billy .i could be all way wrong on this right hear

Agreed thread sealer stops this. And Pat your are definitely NOT as you quoted a "dumb mich hillbilly", you have a superb reputation which I much admire. I have read many of your posts and have learnt a lot from you. It is aways good to keep an open mind. Thanks for your reply.