I'm going to put on a HD oil cooler on my Heritage. Have to take the filter off to mount the cooler adapter. The oil has sumped out of the tank into the motor so if I take the filter off now will the oil run out of the motor? Or do I start it up and get the oil back in the tank? Another question, if the oil is in the tank do I have to drain it first before removing the filter or will it stay in the tank with the filter off? Still learning about Harley's so I'm not sure the best way to do it. I put fresh oil in before I parked it last December but was thinking I would go for a ride, warm it up and change the oil again to flush out the new cooler and lines. Good idea? Thanks for any advice.