How can i find out if my head gasket is gone or the EGR cooler? 2.0tdi 170 2008.

Blowing head gasket often results in water in the engine oil - remove the oil filler cap (engine off!) and look for a whitish emulsion around the inside of the cap = water getting in somewhere. Another quick check is to let the car stand (engine off again) for about 15 minutes after a run then pull the dipstick and look for water droplets in the oil on the end of the stick.

 

Other signs can include water levels in the cooling water reservoir going up and down as the car is revved up (with the pressure cap in place) plus possibly scum in the reservoir..

 

Can't help on the EGR but I'm sure someone else will jump in ...