Re: 3.0 l oil leake around timeingcover seal
Did you center the timing cover and seal over the crank before tightening the cover bolts? There's a special tool (like a bushing) that needs to be placed on the crank, to simulate the harmonic balancer and align the seal with crank. I've never used it, but have used a roll of electrical tape with enough tape pulled off to make a snug fit into the seal. This is not perfect as it will be ever so slightly lopsided and the seal will not be 100% dead center, but I've replaced that seal on a couple engines using an electrical tape roll and haven't had it leak.
FYI, the ID of a roll of electrical tape is the same OD as the crank snout, or close enough. I used a mic to get the thickness of the roll all the way around, as even as possible.
Either that or the cover gaskets are leaking, or there is another leak somewhere else.
Also, check to make sure oil isn't leaking through the balancer to crank press fit, it's possible. And, was sealant used while installing the speedi-sleeve?