Where is the oil filter on this car?

My friend has an '89 Buick Skylark with a 2.5L 4cylinder engine, and he can’t locate the oil filter on it. His dad, an ASE certified mechanic of 40 years, can’t either. He looked it up in a Haynes manual, and that still didn’t help. Anyone know where this thing is located?

It’s in the bottom of the oil pan. Besides an oil drain plug, there is an oil filter access plug to remove the filter housing.

Thanks! I told the guy, and presumably he’s going to check for it tomorrow after he gets paid and can do some work on the car. Once again, the Dope follows through. I love this place.