What version of ez do you use? What happens if you try to clear the cache using the admin interface - any error messages (enable full debug output before)?
Does the script \bin\php\ezcache.php work? (look in the file for the different options)
Does ez at least try to cache the cache (meaning reloading the page after clicking on clearcache does take a while)?
Does the cache clearing work if you do it directly on the setup tab of the admin view? Does the cache clearing script work? Maybe also play a bit with the finegrained cache control, maybe you can pin the problem down to something specific.
I've got the same problem.
When I update something in the admin interface I need to clear the cache manually (button in the admin interface) to see my changes.
For example: if I change the sub-items sorting from "Published" to "Priority" I need to clear the content cache to see the priority fields where I can enter the priorities. Same for content change.
I confirm that my site caches all content. It takes a long time to access pages when I clear the cache.