Treat it to a nice drive on the highway.

Unless the knock is isolated to one cylinder, it's probably just air in the lines -- takes a while to blow it all out.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!