I'm replacing the valve cover gasket on my '02 Subaru Legacy Wagon, and the kit I got came with the valve cover gaskets, grommets, and spark plug seals. Everything looks good in the kit and is fitting properly, but the only thing I noticed is that the old seals have a wider flange than the new ones. I've attached some photos for comparison.

 

Here you can see the old on the top and the new on the bottom:

 

 

Here they are mounted on the spark plug tubes for illustrative purposes, old on left and new on right:

 

 

I was going to replace everything with the parts from the kit, but it seems like the old seals are in pretty good shape. Do you think the wider vs narrower flange will make a difference?

Actually, the difference is more obvious when I line them up on the valve cover itself.

 

 

I think I'll stick with the old ones, although I'm wondering why the kit would have come with the wrong width seals. Everything else was correct.

 

P.S. I did clean the gunk out of the valve cover after taking this photo. :-)

Edited August 29, 201510 yr by prwood

Asking for leaks by reusing that old tube seal.

 

The old ones look wider because they've been squished flat under the valve cover for 13 years. The new ones will flatten out the same way once the cover is installed.