Oil Plug on Side of Motor (might not be timing chain leak)

Nubie, so forgive if this has been talked about.

I thought I had a timing chain cover leak for a while now. So I was flushing radiator last night and decided to track down leak. There is a bolt on the passenger side of engine block, you can see from the wheel well, It is front of the coil spring as you look. Only bolt you will see there. Otherwise it's hard to spot. My oil leak was coming from that bolt.
I looked all over net couldn't find anything about this bolt. So I gambled and took it off. It is an oil drain plug bolt that has a small screen. The screen may come out with bolt. Mine didn't. screen is about 3" long and just slides on the end of bolt. The only thing I can think of is it's a screen filter for the timing chain. The bolt is right where the chain would line up. Just above power steering pump.
So I decide to go get a new crush washer for this bolt, and low and behold my leak is fixed. Also there was a very slight rough idle, that went away, and it reduced the heat coming to the top of the engine compartment.
Again, Nubie here. But I got so much great stuff of this forum, had to share.