Check fuses, you may get lucky on fixing the heater fan. There are many posts on here about the fan.
x2 for lube speedo cable
there are posts on here about odometers not working .
There is a lot about tacho's on here, do a search.
Make sure you change the oil regularly & change the fuel filters.
The valve gaps need setting regularly
make sure you always allow it to glow before starting, especially in the cold.
If you plan on using WVO expect trouble. Many of the head ache's on here are related to that.
Read the owners manual.
Change the trans fluid if it hasnt been done lately.
Have fun with your Merc, they are great cars, & will run nearly for ever if you look after them.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving