If the original air filter O-ring is not removed from the port, the new air filter and the new O-ring will not seat and seal properly. (Another indicator - if the new filter does not fit properly, the mounting bracket will not fit properly.)
If the new air filter is not seated, sealed, and mounted properly, oil vapor or mist will escape through the O-rings during vacuum cycle.
Please refer to this link for information on how to replace the air exhaust filter.
Minipack does not assume any responsibility or liability for the advice given and shall not be liable for any direct, indirect, special, incidental or consequential damages in connection with the use of this information.