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Greetings all. I have a 1966 289 with 110,000 miles on it which has developed a small oil seepage (about 1/2 teaspoon per 100 miles) coming from the front of the engine where the intake, head, and the engine block converge ("the wall" ?). It is pooling just behind the timing cover adjacent to and below the distributor hold down (see photo). From what I can gather, this may be common among SBF's with high mileage and am curious as to what I can do to stop it short of tearing the top end off and re-gasketing. Has anyone had a similar experience and if so what, if anything, did you do to stop the leak?
66 289.jpg
 

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Easy answer- there is no easy answer. You'll need to remove the intake and or the head depending on where it's actually leaking from. You'll know once you pull the intake if you need to go further or not. While it seems like a big job, it really isn't. I'd weigh just how bad the leak is vs how clean you want the engine to be. Most of mine all mark their territory a little bit in various spots- I'd probably go broke trying to reseal them all! lol
 

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You will need to pull the intake, its no big deal. Lay something down in the lifter valley to catch anything your scrape off from getting inside the engine and keep that stuff out of the intake ports. Clean the bare metal real good with acetone or brake clean until a white paper towel is not showing any dirt on it. Put studs in the heads, hand tight where the four corner bolts of the intake go. Use Gasgacinch adhesive on the side gaskets. Glue them to the heads. They have a little wiggle room so try to line them up best you can with the ports. When your ready you just drop the intake over the studs and its all lined up. You don't disturb your front and rear gaskets that way. Once you get some of the other bolts started you can remove the studs and stick the corner bolts in.

Its real important to stick a dab of silicone in each corner where the side gaskets touch the front and rear gaskets because that is where they leak. The hardest part of this project is scraping the gaskets and cleaning everything up

If you want to keep it looking like a 110K mile engine that has never been apart do not paint the intake.

Some gasket sets use cork gaskets for the front and rear. If you use silicone on them the gasket can slide out of place when the intake is tightened down. On the cork gaskets glue them to the block with Gasgacinch. Then you can put a little bead (1/8" wide) across the top of the cork gasket and in the corners.

Some of the gaskets are rubber and have lips to hold them in place so they can't slip out of place. Those do not need any sealant except in the corners.

Some people like to eliminate the front and rear gaskets and instead they run a thick bead of silicone across there. That seals real good. You just don't want a bunch of silicone squeezing out, it looks real amateurish. On a vintage car you should not be able to see any silicone anyway. I prefer to black silicone, Its just about all I used as a fleet mechanic. And if it does squeeze out its not as visible as the blue or the red.

If there is any electrolysis pitting on the heads and intake around the coolant passages you can get a coolant leak, even with new gaskets. If there is pitting then I use silicone just around the coolant passages on both sides of the gaskets. The silicone fills in the imperfections. Gasgacinch rest of the side gasket to the head so it cannot slip.
 

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Are you 100% sure it's oil? or might it be coolant? That's a usual spot for coolant to gather if the water pump gasket is leaking. Stick your finger in the fluid and give it a sniff.
 

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I second awhtx's suspicion about leakage past the distributor o-ring.
 

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I had something like that in a mustang I owned back in the 80s. I ended up just watching the oil level and letting it seep until I did a full engine re-build. The PITA factor to re-seal was bigger than topping off every few months.
 
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