Leaking Valve / Rocker Cover

[X5Kiwi]

The left side valve / rocker cover is leaking in my 2000 4.4 X5, and it is booked in to get repaired this thursday by BMW under warranty.

Any suggestions on other preventative maintenance that I should get done while they are at it?

FYI the symtoms of the leak were a few drops of oil on the floor of my garage, and also today some wisps of smoke coming from the vents on top of the bonnet / hood when I stopped at the traffic lights.

The BMW technician that had a look said that it was quite common, especially since my X5 has done 156000km (97,000miles). However he also said it looks like the cover gaskets had been replaced before, but not done correctly as there is glue all the way around the cover, not just in the certain points that BMW recommend.