Regular oil and filter changes, as with any IC engine.  Add to
that, Fuel filter changes on a regular basis, and draining the bowl on
a water separator, if there is one.  Clean fuel is the `sine qua non'
of diesel operation.
    Dependent on make and model, some diesels still have
mechanically-adjustable valve lash.  Best to have it checked according
to mfr's schedule.
    Less frequently, cleaning and testing of the injector nozzles.
Usually in response to complaints about rough running, smoky exhaust,
etc.  Best performed by someone with experience.

Fluid changes (coolant, brake fluid etc.), belts & hoses are the same as
with gasoline cars. Oil changes & fuel filters on a diesel usually need to
be done more often than on gasoline cars.  There is no ignition system, so
no spark plugs or wires to worry about.

On 9/4/06 8:22 PM, in article
1157419379.041333.327520@m73g2000cwd.googlegroups.com, "bowgus"

If you can find a manual for your engine, read the maintenance section.
The manufacturer usually knows best.
I see you are in Canada (Toronto area).  If you buy fuel in the USA: Ultra Low
Sulfur Diesel will be the only fuel available soon.  Better check with a mech/tech
to see if your engine will need new elastomer seals if you buy fuel here.
I don't know if Canada is going to ULSD or not.