1985 300d no-start + coolant leak
 

I acquired a 1985 300d last summer. As the weather got colder it would be hard to start sometimes, but ran well once the engine warmed up.

When I went to start it last week after sitting for several days it cranked over fine but would not fire at all. Also while I was trying to start it, I noticed that there was a puddle of coolant forming on the ground near the front of the engine and that the expansion tank was nearly empty.

I've ohmed out the glow plugs and confirmed that the relay is working.

Last weekend I ran a compression test, and it has good compression on all 5 cylinders. I also pulled the valve cover and adjusted the valves.

I loosened the fuel fitting at the output of the main filter housing to confirm that fuel is getting to the injection pump. I saw fuel spraying from that line when cranking the engine so it looks like the lift pump is working.

Now it sputters a little and shoots some smoke out the exhaust when cranking, but will not run.

I'm thinking I may need to pop test/rebuild the injectors? Not entirely sure though. Let me know what else y'all think I should try.

Thanks for the help!

Coolant at the front of the engine is likely the water pump.

Regarding the non starting....
5 Injectors wouldn't all of a sudden start spraying bad patterns/leaking/not firing.
When you did the compression test I'm guessing you removed the injectors? You'll need a lot of cranking to get fuel back through the lines and to the injectors if they were removed. I used 2-3 charges of my jump box of cranking before the car began to fire last time I took apart the lines to the injectors on an om617. When the lines are loose at the injector side does fuel come out?

To test the glow system, did you follow this guide or perform something similar where you test ohms through the entire system including the wire to the plug?
https://www.dieselgiant.com/glowplugrepair.htm

Your symptoms sound glow related.