Okay, please be kind. I have a dumb question to ask that is probably
obvious to everyone but me.

I notice that in replacing the heads on the Vanagon waterboxer they always
list the sleves out of the case too.
What is the reason for doing that?  Why can't you just pull the heads off,
and replace them leaving the sleves in place?

I know that I'm missing something obvious here - but can't figure out what.

Thanks,

Todd
'88 Westy with leaking head.