Choose the main problem

Poor cold starting
Heavy fuel consumption
Poor performance or acceleration
Stalling / Hesitation / Flatspots
Rotten egg smell
Pinking & pre-ignition
Wear of diesel fuel pump
Diesel knock / Cabin noise
Coolant leaks
Inefficient cooling/heating
High exhaust emissions
Blue smoke at start-up
Blue smoke when accelerating or changing gear
Black smoke (petrol)
Black smoke (diesel)
Blue or black smoke
Excessive oil consumption
Engine oil leaks
Low compression or oil pressure
Black sludgy oil on dipstick
Tappet noise / Sticking hydraulic valve lifters
Top end engine rattle
DPF warning light on
Clogged DPF
Clogged diesel fuel filter
Excessive noise /fuel consumption