changed oil today. for the third time(on 3 different xj's) the ratchet part of the oil filler cap broke. This leaves you with one part of the cap in your hand and the other still in the valve cover. As I did previouly, I mixed up a small batch of Devcon plastic welder. I put it in the open part of the cap in the valve cover and then replaced the other part. I waited about 10 minutes. The cap still still works(no ratchet anymore but I really don't care).