Hmmm...let's see. Remove air cleaner assembly. Remove four 10mm bolts on each valve cover and lift.
Now comes the hard part. Peel off the old seals, which are probably hard as a rock and thouroughly clean the mating portion of the cover. Next thouroughly clean the mating surface of the head, be sure there is no oil what so ever on the mating surface. Pop the covers back into place.
Now the hardest part. Tighten the four bolts enough so they don't leak but not so tight as to cut the new seals. I don't know what the torque for the cover bolts is so I use a 1/4" drive rachet and just snug them up. Haven't had any leaks from the two V-8's I've been into.
No, you don't have to drain the oil. While you have the covers off you should check and adjust your valves while you're in there though.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.