I am tired of chasing this leak, and so hopefully somone can shine some light on this problem I am having. I recently put in a new intake and carb and valve covers to my 305. she runs great, but every now and then i find a leak under the right side of the car. i have tried re-tourqe on the bolts, changing the gaskets. what is confusing though is that i will have a leak under the car but there is a little pool of oil in the wells of the intake by the bolts. so i tried sealing around the intake again. there is noindication of leakingwith theright side of the engine (driver side). and it is only coming from the frontleft as far as i can tell...if anyone has any ideas i would most appreciate it.

 

If you’re getting oil on the intake it is coming from the valve cover. No oil flows thru the intake. They only leak on the ends and that’s from cam splash, normally it just gets the engine wet not a puddle. The process of getting a Pre-1987 305 valve cover to seal is pretty touchy. Bolts on a light too tight, they leak, a little too loose, they leak. Not perfectly clean, they leak. The wind blows from the NE at 7 miles per hour while you are installing them, they leak. Check out a manual for process, every time this issue was brought to me at the dealer it was because the bolts where over tightened. In most cases I had to use a hammer and dolly to get the valve cover back straight. Then follow the process in the manual.

GM used to offer a kit that has studs and extra long supports that make it easier to get them to seal.

 

thanks gorn...i will do that...

 

Not necessarily. Misfit79 said he is finding oil around the intake bolts and in the wells of the manifold. Oil can push it's way up around the threads of the intake manifold bolts from inside the head (where some of the bolt holes come through). If you are seeing oil around an intake manifold bolt and in an adjacent well as you described, then that's how it's getting there. Putting a little silicone sealer on the threads of the intake manifold bolts, after cleaning off the oil with a solvent, should take care of it.

 

I was a GM goodwrench from 1984-1989 I have fixeddozens of 305 with oil on the intake. I have never removed an intake bolt to do it. There is no seal on a intake bolt and the threads are not pipe threads. Oil pressure canhit 60 PSI anyplace thatit can reach will have a seal.GM never intended for those bolts to seal out oil. If you have oil coming from those bolts you have a crack somewhere in the head and you are asking the intake bolt to do something it was not designed to do.

So I stand by my earlier statement. If you have oil pooling in your intake it is coming from your valve covers.

 

Huh? I presume then that you're suggesting that the 305 heads don't have threaded intake holes that go all the way through to under the valve cover?
In my over 30 years of shadetree mechanics experience (sorry, I don't have the illustrious Goodwench designation), I have more than once had oil pooling around intake bolts that in absolutely no way made it there from the valve cover, nor did it begin it's trail from the head/manifold valley and climbed up and over the ridge of the intake manifold without leaving tracks. From where I sit, I stand by my earlier statement too...so there!!!

 

Are you saying that put RTV silcone is something the factory requires everytime an intake bolt is removed? Its required from new and its the best way to seal up a bolt? All those Valve cover jobs I did didn't really fix the problem yet no one complained? GMdid not admit the issueand come out with valve covers add on kit to fix it?And your sure of it cause you work on car as a hobby. How may 305's with oil on the intake have you repaired? Or did you read it in a post somewhere?

 

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Gorn, you didn't answer my question whether or not the 305 head has some intake holes that go all the way through to the oil valley where oil can get to them? If they do, then they are typical SBC heads as I'm referring to. Also does GM put a thread lock/sealant on their bolts from the factory, or no? I'm not saying that the issues you had weren't valve cover related, I’m sure it was. My point is that there IS another way for oil to make it's way onto the manifold and wind up smack-dab in the middle of nowhere (coincidentally around an intake manifold bolt too). And no, it's not something I read in a post somewhere; it's something that my own past experiences (and others who I know as well) have taught me. Apparently you haven't had this experience before, but trust me, it happens. And who's to say that I can't know what I'm saying just because I’ve spent many years working on and restoring cars only as a hobby, and not for a living? Believe me, I've met more than one "certified mechanic" who doesn't know his *** from a hole in the ground! We could also talk about why coolant sometimes likes to weep around a couple front manifold bolts too, just like the oil does on others, but I’m not opening that can of worms at this point.One thing that I can think of that might contribute more than normal to the oil leak around the manifold bolt issue could be the use of stainless steel or chrome plated (slick finish) bolts that a lot of us hot-rodders like to use.
These links are just to show that I'm not the only one who's experienced the "mystery" oil around the intake bolts: http://www.hotrodders.com/forum/inta...ak-131761.html
http://ls1tech.com/forums/archive/in.../t-794978.html

 

Trouble Maker!!! [8D]