First things first make sure you drain the oil, once that's done you need to remove the air cleaner housing. There should be 3 or 4 nut 10mm nuts holding it on, once all three or four nuts are off remove the air cleaner, once that's off you can easly access the oil filter, just unscrew the nut off the lid and remove the old filter and drop in the new one.
Why does my fuel pump keep running on my 1984 190E
Buy a Hayne's manual for the Mercedes diesel or a Chilton's manual for Mercedes (it has a 123 Mercedes on the cover). It will show you how to change the inline fuel filter and the main fuel filter.
Take it to a mechanic
For a 190E 1984 Model, it is about 60Litres, this is 13 Gallons(UK) or 16 Gallons(US). For a 190E 1993 Model it should be the same +/- 5Litres.
On my 1984 190E, it is simple - there are a couple of tabs at the bottom of the back seat (where your heels would be if you were sittng), you have to look, the seat will pull right out!
There is no such thing as a 1998 190E, BTW - It was replaced by the C-class in 1993... On my Mercedes (1984) there is no cap lock, when you lock or unlock the doors, the gas latch (door) is locked or unlocked automatically.
It is located behind the battery. Lift up the black cover and there it is
There are two possibilities. Its either on the overhead console by the rear view mirror or on the center dash control switches below the heater vents.
This model has mechanical linkage in the door so you just have to keep trying to hook the lock rod. It's not really hard but you have to just keep trying.
See my tutorial on this at the following link http://www.benzworld.org/forums/w201-190e-d-class/1358590-troubleshooting-mercedes-benz-190-e-d-210-tempmatic-climate-control-system.html#post2716281
At servicing/oil change I use approximately 6 litres of engine oil
Mercedes Lander was born on January 25, 1984.