Oil leak on top of valley cover

Well, title says it all. I have standing oil on top of my valley cover. It leaks primarily off the front of the engine, but some off the back as well. There was no standing oil inside the intake. Lots in valley pan holes where the knock sensors go though. The front knock sensor was completely submerged in oil. I replaced the valley cover gastket, knock sensor seals, valve cover gaskets, intake manifold caskets and checked all my vacuum plugs, oil pressure sender, etc. Anyway, it's still leaking. I can see oil drooling off the front of the valley cover and down the timing cover already... Any ideas?

Much thanks,

JP

There must be some damage to one of the surfaces. You will have to take apart and check for any nicks or marks. Other than that you could add a little silicone to help fill the surface imperfections.

Thats what I was thinking too, but upon inspection everything seemed fine. I cleaned all the surfaces as well. I suppose something could be out of square, but it was a 70k motor that had never been blown apart, so something just seems fishy. Am I right in thinking that I've addressed all the likely locations it would be coming from?

My only other thought is the PCV system. I'm still running the LS1 valley cover. For my PVC I've run the rear of the drivers side valve cover (with smaller valve) to the throtle body. I then capped both sides on the front of the intake, as well as the passenger side valve cover. Just FYI in case I botched it all up.

Thanks

I bet the oil is coming up through the front knock sensor. I figure your valley cover may be warped or damaged around the front knock sensor. Check the block where the knock sensor gaskets seal against also.

I'd get the easy stuff sorted before digging deeper in there again. The PCV could cause oil leakage up top and it doesn't sound like you have it right.

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Thanks everyone,

I'll try messing with the PCV system first, then look into the valley cover again if that doesn't work. My current PCV setup was inspired via a post I saw on here to reduce the tjypical LS1 oil consumption, but until I figure this out I may just have to deal with that.

Out of curioisty, if it is the PCV system, how the hell is it getting onto the top of the valley cover? Too much crankcase pressure?

Cheers,

JP

Too much case pressure is blowing the oil out the weakest hole/gasket is my guess. Two ways to fix - the right way is to see why you have too much crank case pressure (hint: it's your rings!). The cheaper way is to increase your crank venting to reduce the pressure.

I would start by taking both valve cover vents and running them to a catch can - a coke bottle would work fine. Run then engine a bit and see how much oil is collected and if the oil still pools on the valley cover. That will tell you how bad your problem is.

You might also want to check your intake to see if it's covered in oil.