ZEST BOLT Service Manual

Revotron 1.2T 15 Engine emits blue smoke from tailpipe Worn or damaged valve guide seals • Remove rocker arm cover and inspect valve guide seals. Replace as necessary. Engine crankcase overfilled with oil • Check oil level; drain oil as necessary. Worn I damaged piston ring(s) or cylinder bore, permitting oil blow-by • Perform engine compression test and/or leak-down test. Head gasket leaking oil into combustion chamber • Inspect engine coolant for oil and perform engine compression test. Engine emits black smoke from tail pipe Excess carbon deposits in combustion chamber • Remove carbon deposits in combustion chamber using a commercially available cleaner Excess fuel entering cylinder(s) • Check lambda/O2 and other engine sensors for proper operation. • Test fuel injectors for proper operation or leakage. • Check the fuel and emissions system for proper operation. 6. Cooling System Condition Possible Cause Remedy Overheating Low coolant level/ Cooling system leaking • Check coolant level in reservoir and inspect system for leaks. Add coolant as necessary. Defective thermostat • Remove thermostat and check for proper opening at specified temperature. Defective water pump • Inspect and replace water pump as necessary. Defective temperature sending unit • Check coolant temperature sending unit Replace as necessary. Engine cooling fan malfunctioning • Test operation of engine cooling fan. Repair or replace as necessary. Engine overloading • Make sure vehicle brakes are not dragging. • Vehicle overloaded. Make sure vehicle does not exceed weight limit with cargo. Engine lean condition • Verify proper operation of fuel system components. Repair system or replace components as necessary. Head gasket leaking • Test engine compression. Replace head gasket as necessary. Over cooling Defective thermostat • Remove thermostat and check for proper opening at specified temperature. Defective temperature sending unit • Check coolant temperature sending unit. Replace as necessary.