valve cover.

[jwill22]

whats the difference from having an aluminum one to a plastic one.. mine has a plastic one on it..

84 cj-7 . 5 speed

 

[Zuni]

The plastic ones are more prone to leaking. I have an Aluminum one on my CJ (came with it) and I haven't had one issue with leaking at all.

 

[BrockGrimes]

The difference is plastic or aluminum, but as stated above the plastic ones leak.
Check you local junk yard for jeeps. You have a 258 4.2l?
If so look for those AMC eagle station wagons they have the aluminum 258 valve covers.

 

[CJ]

whats the difference from having an aluminum one to a plastic one.. mine has a plastic one on it..

84 cj-7 . 5 speed

IMHO - If it's not leaking, leave it alone but find an aluminum one for when ever you have to work on the valve train or if it does start to leak... To many times we get caught up in the 'what is best' scenario when what we have is working perfectly fine...