When its cold and I start my 96 f350 turbo diesel it leaks oil does not leak when above 35 degrees

The metal shrinks when cold, opens a gap and oil leaks out. Where is it leaking from? Filter? Valve cover?

Can't see where its coming from but it leaks down at the front drivers side of truck the colder it is the more it leaks when its really cold a quart or more 20 degrees or less