Exactly how I did it after I figured out my inspection mirror did not fit the oil filler hole.All is good!Here's one solution: The inspection camera has a tiny mirror attachment, set at 45 deg. on the tip. It gave me a slightly out of focus image, but was good enough to see that the plunger was extended. These cameras are $75 at Harbor Freight, and can be found for under $50 at discount outlets. These suckers pay for themselves when you're in a pinch.