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BMW DIESEL 1 FAULT DIAGNOSIS COOLING SYSTEM FAULTS This section covers mechanical faults that could occur Before conducting any visual checks within the See Description and operation. 1. ENGINE (COOLANT) COOLING SYSTEM Symptom - Engine Overheating POSSIBLE CAUSE REMEDY 1. Engine coolant low. 1. Allow engine to cool. Top up expansion tank to correct level, with engine running at idle. Check cooling system for leaks and rectify if 2. Loose drive belt. 2. Check/renew drive belt tensioner or renew drive belt. See ELECTRICAL, Repair. 3. Coolant in radiator frozen. 3. Slowly thaw and drain cooling system. See Repair. 4. Air flow through radiator restricted or blocked. 4. Apply air pressure to engine side of radiator to clear obstruction. If mud or dirt is evident, carefully use a hose. 5. External leaks from water pump, engine gaskets, 5. Check for visual causes and rectify. 6. Viscous fan not operating correctly or inoperative. 6. Renew viscous fan unit. See Repair. 7. Thermostat seized in closed position. 7. Check radiator bottom hose for coolant flow through radiator. If cold a faulty thermostat is confirmed. Renew thermostat. See Repair. |