Overheat
- Insufficient amount of coolant in the system (Weekly check).
- Faulty thermostat (Chapter 3).
- Clogged radiator or grille (Chapter 3).
- Faulty electric radiator cooling fan or coolant temperature sensor (Chapter 3).
- Temperature gauge malfunction (Chapter 3).
- Air lock in the cooling system (Chapter 1).
- Faulty radiator cap (Chapter 3).
Hypothermia
- Faulty thermostat (Chapter 3).
- Faulty coolant temperature gauge sensor (Chapter 3).
- Viscous coupling failure (Chapter 3)
External coolant leak
- Damaged hoses or clamps (Chapter 1).
- Leak through radiator or heater heat exchanger (Chapter 3).
- Faulty radiator cap (Chapter 3).
- Leakage at coolant pump seal (Chapter 3).
- Internal water pump leak (Chapter 3).
- Boiling off liquid due to overheating (Chapter 3).
- Leaking rod plugs (Chapter 2).
Internal coolant leak
- Leakage through the cylinder head gasket (Chapter 2).
- Crack in the cylinder head or in the cylinder block (Chapter 2).
Corrosion
- Infrequent fluid changes and flushing of the cooling system (Chapter 1).
- Wrong coolant composition or wrong type of antifreeze ("Weekly checks").
Power supply and exhaust systems
Increased fuel consumption
- Clogged air cleaner element (Chapter 1).
- Incorrect choke adjustment or choke sticking - carbureted models (Chapter 4A).
- Fuel Injection System Malfunction (Chapter 4B).
- Fuel Injector Malfunction - Diesel Models (Chapter 4B).
- Incorrect ignition timing or malfunction of the ignition system (Chapters 1 and 5).
- Insufficient tire pressure ("Weekly check").
Fuel leakage and/or fuel smell
- Damage or corrosion of the fuel tank, pipes or connections (Chapter 4).
Excessive noise or soot from the exhaust system
- Leak in exhaust system or manifold connections (Chapters 1 and 4).
- Leakage through a rusted or damaged muffler or pipes (Chapters 1 and 4).
- Contact of the exhaust pipe with the underbody or suspension due to damage to the fastening of the exhaust line (Chapter 1).