You may have bad glow plugs but they won't cause the engine to die. Remember once the engine is started the glow plugs shut down and thats it for them.

It sounds like a fuel issue.

First remove the spin on filter and make sure you didn't fubar the gasket around the threaded hole that the bolt goes in. Also replace the two orings on the bolt.

You can bypass the fuel heater, maybe try running another tank direct to the pump and see if the problem goes away.

I'd almost suspect your lift pump is getting weak, becuase even with an empty filter it shouldn't take a half hour to bleed the air out of the system.

I'd also start splicing in clear lines, look for bubbles you may have an air leak as well.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200