Sounds like the original poster expected to find compression seals like in the 61x engines.

My guess is the compression leak is unrelated to using biodiesel. Just a coincidence.

I use a magnet to remove the injector seals. Once I did a compression test without removing the seals and they all jumped out. If they're stuck, try cranking the engine with the injectors off.

And I'm not the only one who calls them heat shields

Sixto
93 300SD