The time that it takes you to open the hood allows the engine to recover from the first couple of starting attempts...If you will glow the plugs 2-3 times for the full duration, it should start...I would also install a block heater. They make a WORLD of difference on the diesels.
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM