Hey guys,

So I had my law built this year by a local engine shop. All brand new gaskets, fresh hone hon rings, new bearings, and some aftermarket goodies. Car made 425ho and 400tq on a Mustang dyno.

Since I got the car back I've noticed the bottom of the pan and front leaf wet with oil. I've cleaned it up a couple times trying to determine what's leaking. What I can see so far is it appears it's from the front main or the front oil pan gasmet, but I can't tell for sure as it only seems to leak when I'm.out driving the car. Idling in the garage yields no leak.

Before I pull the rack and replace a new main seal with another one, anyone have much experience with this? I've read lots of stuff about crankcase pressure and oil slosh, but I don't think it applies here, as I have not autocross the car yet, it's just some spirited driving during a commute to work and back.

I have a fast 92mm intake with ls2 tb, and have removed the vacuum pump with the headers. The PCV system is currently plumbed directly into my intake piping with a nipple for a venturi, similar to the stock set up was before the swap. I have checked the PCV valve and it seems to be functioning.

 

Can you see any silicone coming out of the 2 front corners of the oil pan where the timing cover contacts ? That is a common spot to leak if it wasn't sealed. Also how old is your crank pulley ? Could have a groove worn in it from the past seal and the new seal wont keep it tight.

 

Initially, to see if it was the oil pan gasket leaking I covered the front pan gasket area with right stuff, trying to see if it slowed down at all and didn't seem to make any difference, which is why I'm leaning toward the front main seal as the source. The crank pully is fairly new, replaced just before the engine was built.

My main concern is if the issue is a bad brand new main, or excessive crank case pressure at rpm that's squeezing oil past the seal. I'm going to look tonight. D double check the PCV system if plumbed correctly after the rebuild.