I am a 03 pre-order Z owner with 13k and have all the Z problems mentioned in this forum. Just when enough problems were'nt enough, the other day i decided to open the hood and do a quick visual inspection and discovered that my valve cover gaskets were leaking. No oil has dripped on the exhaust manifold yet, but there is some kind of seepage for sure between head and valve cover. FYI my last oil change I went synthetic(dealer), I wonder if this is the problem. To all Zers take time to do a visual check if you have'nt done so. Check your belts one of my belt min was replaced at 10k belt was falling apart, was being pushed back.

 

I had the same problem on my preorder and no syn oil at the time. Check on top of your cat converter. You may see seepage on that. That's how I noticed mine. NEver saw oil on the ground.

Dealer repalced gasket and tightened to cover.

 

took mine in getting new gaskets. I guess people do'nt look under there hoods thinking its a new car for what.