"Has anyone cleaned the holes but NOT replace the glow plugs after? Did u notice any improvement?"

It will not start if you don't replace the glow plugs.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked