Identify this 300D engine sound: MP3 included

[DieselFitter]

Dear Diesel Demons:

Every five or so start-ups My '83 300D makes a strange noise just after cranking over. I'd describe the sound as a metallic creak, like something's opening up improperly. I wish I could be more descriptive but I decided to record it instead. You can hear it at: 300D Startup - the sound I'm worried about occurs 3.5 seconds in. Another tip: it seems to be worse in cold weather.

All best,

Diesel Fitter