So the service writer called me at about 10 minutes to 10. So the 2 hour diagnosis took less than 2 hours... in fact it probably took 2 minutes.
Anyway, he told me all it needs is a glow plug (duh). But that's $22 for the plug, and 2 hours to install it. I asked the guy to apply some of the $200 diagnosis fee towards the repair. Hopefully he'll be able to help me out, but I'm not holding my breath.