Retorqued Intake but still seeping oil between intake/heads

[Jack O.]

I only have about 3 or 4 hours run time after completely R&R'ing carbs and intake. Just noticed some oil seeping out between intake and gasket in center area of intake on both sides. I checked the intake bolts and they definitely needed to be re-torqued. I was surprised that it would be needed so soon. But in any case, I re-torqued them all but I'm pretty sure I'm still getting the seepage. Is it too late, i.e. once you see oil leak in this manner will I have to replace the intake gaskets to get it to stop?

It's a '69 427/400.

TIA

[Owen L.]

Re: Retorqued Intake but still seeping oil between inatke/heads

I forget exactly which bolts, but know for certain that a few on each side and definitely one of the center two on each side, enter into the pushrod/rocker area under the valve covers. You need to pull one bolt at a time, clean the threads and apply a thread sealant. Then reinstall and torque. Without sealant, the oil wicks its way up the threads.

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[Jack O.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Hmm, Owen you may be on to something. I didn't think of that. Would the oil come from between the gasket and intake as opposed to coming out from the bolt hole itself?

I did clean the bolt holes, used new bolts, and used thread sealer when I first installed the intake (followed all the excellent advice on this forum) but perhaps once they loosened that seal was compromised. The leaking is close to the 4th bolt from front on left and 5 from front on right, which I believe are "through" bolts, but as I said, definitely coming from between gasket and intake..

[Owen L.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Well, it sounds like you did all the normal installation procedures.
I assume you torqued from the center outward in the recommended pattern?
Did you use any kind of gasket spray?

You might try pulling the two bolts out entirely to see if oil is all the way up the threads. There isn't anything in that location other than the intake ports and securing bolts, so it seems it has to be coming up the bolts.

I doubt you really want to go there, but if more sealant doesn't address it, perhaps a new gasket with smears of black rtv around the bolt holes on each side is in order.

[Jack O.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Yep, followed the torque sequence. I used just a bit of Permatex Ultra copper just around the water outlets and used GM NOS intake gaskets acquired from another forum member. Everything was tight and pretty for the 3 to 4 hours I ran it. I had to pull the carbs and send them back to the rebuilder and so the engine sat for about 3 weeks. Put the carbs back on and running it checking for carb leaks and up pops these intake leaks. I meant to check the intake bolts while the carbs we're off, especially since it's so easy then, but forgot. I'm pulling the bolts tonight to see how things look and redo the sealer.

Thanks for the help and input Owen, much appreciated.

[Michael H.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Thread seal all of the intake bolts. Do one bolt at a time if they are already installed, clean the bolt and the threads with brake clean let air dry, Then torque as required starting in the center of the intake. Let it sit for a couple of days then start it up.

Mike

[Owen L.]

Re: Retorqued Intake but still seeping oil between inatke/heads

I used just a bit of Permatex Ultra copper just around the water outlets and used GM NOS intake gaskets acquired from another forum member.

If by sealer you are referring to the copper, then that could be the problem. The copper is an anti-seize lubricant and not a sealer. The Loctite above is a dedicated sealer. Permatex makes one too but I don't know their brand name for it. Whatever you use should have "high temp" compatibility.

When I did my intake earlier this year, I put the Loctite on the lower 1/2" to 3/4" of each bolt by running my finger around it to spread it into the threads evenly; not globbed on but filled the thread valleys. So far no issues with leak through. One of the little .20oz tubes was enough.

[Jack O.]

Re: Retorqued Intake but still seeping oil between inatke/heads

I only used the Permatex on the gasket just around the water passages - another recommendation I took from this forum.

I used ARP thread sealer on ALL the bolts and used brand new bolts too. Cleaned the holes and the bolts really well. I will give it another go.

[Michael H.]

Re: Retorqued Intake but still seeping oil between inatke/heads

I use Permatex Aviation Form A Gasket No.3 on all of my bolts on the intake. No leaks what so ever.

Mike

[Jack O.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Roger that. I'm going to "redo" each bolt close to an area where it's leaking. I was wondering about the dry time though. I used the ARP sealer on a couple of my carb bolts and the stuff appears to stay sticky. I also have the Locktite brand thread sealer. But when I originally assembled everything it had over a week to cure.

[Jack O.]

Re: Retorqued Intake but still seeping oil between inatke/heads

So pulled the bolts and no absolute smoking gun but they did have just a very little bit of residue so I'm hoping redoing them does the trick

On another note, everyone knows what a pain it is to try and torque these intake bolts when the carbs are mounted. I bought some extenders but at 2" they only helped with a few of the bolts. So I made my own out a stubby wrench, 4" long, by putting a nut and bolt. with washers to hold it into the open end of the wrench. Worked great! I also saw a demonstration video where if you keep the extender at 90 degrees to the wrench it doesn't throw off the torque (since it maintains the length). I tested it myself too.

[Richard G.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Jack Ottofaro if you use Loctite 567 you will find it's an anaerobic threadlocker.
Meaning it hardens in the an absence of free oxygen.
It will work perfectly and is designed for just this type of scenario.
Permatex will also work and is likely easier to source and less expensive.
Rick

[Jack O.]

Re: Retorqued Intake but still seeping oil between inatke/heads

Thanks Richard. Will try that if I'm still having issues. My biggest issue will probably being cleaning the female threads sufficiently - very difficult with carbs in place. The ARP thread sealer was working fine until the bolts loosened so a threadlocker should also help with that too.

[Jack O.]

Re: Retorqued Intake but still seeping oil between intake/heads

So, found the leak. It was actually the valve cover gasket at the top, leaking down into the area between the intake and head. I didn't think to look there at first because it was occurring on both sides and I had just replaced the drivers side gasket and it was not leaking until after the car had sat a couple of weeks. Just like the intake, the valve cover bolts needed to be re-torqued. I not yet convinced I wont have to replace the gaskets.

[Michael L.]

Re: Retorqued Intake but still seeping oil between intake/heads

Thankfully you found it before you went all the way to pulling the intake and starting from scratch.