what is the standard for changing valve gaskets in a 1996 Subaru Legacy outback with 139,000miles on it?
If they are not leaking leave them alone. The option is to take the time to change them while inspecting, cleaning and replacing the covers. I do not believe you need to adjust. That model year were self adjusting.
Valve cover gaskets are not a maintenance item. If they don't leak. leave them alone.
Yup...NO "standard" here.
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