When I replaced my timing belt at 100K miles, I found the lower timing cover was broken and had been rubbing against the back side of the crank pulley. I bought a new timing cover and installed it according to the instructions during reassembly. Recently I replaced my timing belt again at 160K miles, and found the lower timing cover was broken again in exactly the same manner. This time I took the time to figure out the problem.

There's a rubber gasket that is installed around the edge of the lower cover. I ordered it separately only to find that the new cover came with one glued in place. Here's the tip: Remove that rubber gasket and throw it away. The lower cover is **clearly** designed not to have any such gasket, as you'll discover when you fit it up without it. There is nothing watertight about this fitment; the upper cover has no such rubber gasket. The covers really just are dust covers, intended to keep gravel and fingers out of the timing belt.

Further tip: There are two smaller rubber gaskets that fit behind a plastic panel behind the cam sprocket. Omit those, too! If you're not removing the cam sprocket, it's perhaps not worth removing just to get those gaskets out of there, but if you're in there anyway by all means toss those two little pieces in the trash and put the engine back together without them.