As I'm not much of a genius when it comes to car names and parts, Plus, getting frustrated with trying to read the forums and then run to the car with things like (on the left as you look at the car its a black box),
I thought it would be time to get a kind of "map of your engine" thread going, For those like me, who can not get their head around the Haynes manual. And I wanted to give something back to this community for helping me get my car sorted.
I will update this post with info and locations so its easier to find what your looking for, and if anyone can supply photos of other Citroen engines, and item names PM me and i will add them to the thread (if you can pm me that is)

Engine
1.9 turbo
Car
97 Xantia
Engine part and location code
LHM reservoir - M1 to P3
LHM reservoir fluid level indicator - O2
Primer pump - A2
Air filter housing / Box - K5 to N9
Fuel filter - I5
Dip stick and oil top up cap - H5
Alternator - D9
Oil Filter (blue part) - F8
Fuel Pump - D5 - E6
Hydraulic Pump - C7 - D8
Air-Con pump - C7 - D8 (Below Hydraulic pump)
Quick Diagnosis Checks
Turbo sluggish / slow / not working - Check black Pipes (as can be seen in photo) for cracks / air leaks / splits
Engine hard to start from cold and producing white / blue-ish smoke once started - Check Glow plugs, possibly replacement
Engine Hard to Start from warm or cold, check Fuel Leak off pipes on Injectors (Located above Glow plugs)
Strange Grinding noise and smoke / burning smell, from the front left of engine bay, Check Air Con pump clutch to make sure its not seized.
If anyone else can lend a hand with part names and locations or quick diagnosis checks would be appreciated, ill add them to the list.