Actually less oil! It would only take a few drops to see if compression changes. At top dead center, another emission style test can be done. Using a vacuum cleaner. Connect the hose on the vacuum outlet. Connect the vacuum hose to the exhaust. Turn on the vacuum cleaner. Where is the air coming out?

Disconnecting a top intake CCV hose would work. Not the valve cover one.

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'06 X5 3.0i - bought @143,123 miles (12/26/20)