Bizarre Oil Leak From Exhaust Port? Need Help.

It turns out it's not on the seam. The oil is coming right through the metal! Note that there are 2 main spots forming. A big one on the left and a smaller one on the right. These 2 pics are a couple of minutes apart and you can see the spots growing.





There is a slight bulge in the aluminum in this spot. If I'm not mistaken, it's right below one of the big bolts that holds the cam in place. It's like someone, at some point in time, put a too long bolt in there and cranked it down causing a bulge and small leak right below it. I had the valve covers off a few months ago when I readjusted all the valves and I checked the tightness of those cam bolts and they all seemed correct. None were loose.



Maybe someone took the bolt out, some oil got in the hole and then they cranked the bolt back down quickly causing the oil to hydraulicly push down on the bottom side?

I don't know, but I knew it was a bizarre leak.

First repair attempt is to clean the area and apply black RTV silicone. I'll see how it does in a few days or week or so.

 

U can try to seal the boot itself by removing it and applying silicone to the threads than retorqueing it and see if that stops or slows down the leak!

 

Wow the roll it flour and look for the wet spot works with bikes too maybe i'm seeing more than i should be, but it looks like there are some light grinder marks in the area of the two small dots.....

 

Unlikely trapped oil would do that. A small piece of metal more likely.

 

That's more a "plan C" since it involves draining the water and pulling the cover (which is sealed up nicely). If the silicone doesn't hold, "plan B" is to try some JB Weld.

I tried sanding the area down to see if I could smooth it out, but it's so coarse right there, I gave up. A dremel tool would sand it down nicely, though. I might try that later if needed. Especially if I use JB Weld. I'll grind it down to bare metal so it will stick better.

Good point. If I have to pull the cover and bolt out I'll make sure to look down in there real good and use a magnet. Maybe shove a dowel rod in there and measure how far down it goes and then make sure the bolt isn't longer than that. If something is jammed in there I could probably take a couple mm of threads off the bolt without weakening it. Clean the hole good, dip some silicone in there and on the threads and slowly tighten it back up. It's still "plan C" though.

 

Also could be that the hole wasn't tapped all the way down and when they put the bolt in it the presure popped the casting a bit!

 

Try compressed air to remove any foreign debris if you can. Brake clean may work well also. If there is some metal in there it might be non-magnetic (aluminum). So a magnet might not work.

 

So nice work finding that!
As you have already stated, it could have been caused by inserting a bolt that was too long or even trapped oil that was compressed when the bolt was inserted as I've seen that before but either way, what are you planning to do now? Are you going to rough it up and apply a layer of epoxy (JB Weld or other) or clean out the bolt hole from above and seal it from the inside? The area obviously sees quite a bit of heat being so close to the exhaust port but I think the JB can probably handle it. If the head was off the bike, I would just weld it and grind it smooth but that may not be necessary.

It's funny that all this time we (I) was thinking that the oil was blowing past the gasket on the header but that was never the case.:crazy:

 

I'd skip the silicone and just use jb weld. It should hold up to the heat. I think silicone is a waste of time in this instance. Good job tracking it down.

 

I've done quite a bit of riding and the silicone is holding up so far. No signs of oil.

I thought that too, especially when I tightened up the exhuast bolts and it didn't leak until the second ride. It did that twice. Tighten, first ride, no leak. Second ride leak. I still can't explain that. :crazy: