I can confirm a 60 watt shop light will start a 603 with no glow plugs in 0F weather... I put a METAL shield shop light on the EXHAUST side of the head and let the light shine on the exhaust manifold/head. car started up like it was summer time.
now, I know the 61x motors ESPECIALLY the loop plug equipped version is a totally different animal, and there is no "exhaust side" to the motor, there is a FUEL side, and an AIR side, and it'd be safe to set the light on the air side of the motor to start it up.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!