Michigan Mechanic Certification- HVAC
Exam Questions and Answers
Cooling system leak diagnosis - -Pressure test or dye test
- Purpose of a radiator - -The purpose of the radiator is to dissipate heat
that is picked up by coolant in the engine into the air passing through its fins
and tubes
- Symptoms of low coolant - -Engine overheating and no heat from the
HVAC system
- Purpose of the thermostat - -The purpose of the thermostat is to trap the
coolant in the engine until it reaches it operating temperature
- Cause of low heater output - -Low coolant level, clogged heater core,
leaking heater core
- Heater core hose routing - -The supply hose from the heater core should
run from the closed side of the thermostat to the heater core and the return
hose should run from the heater core to the engine
- Heater core operation - -The blower motor blows air through the heater
core fins and is warmed through the principle of conduction
- Heater control valve purpose - -This valve controls the flow of the coolant
to the heater core to control the temperature of the air desired by the
operator
- Radiator cap testing - -To test pressure test it using an adapter and a
coolant pressure tester and the value marked on the pressure cap
- Reciever drier purpose - -May contain a filter or strainer to catch and trap
foreign particles and dirt
- Reciever drier location - -Located on the high side of the system between
the condenser and the evaporator
- Ambient temperature switch purpose - -Monitors temperature by
increasing or decreasing with resistance as temperature changes
- Symptoms of a failing ambient temperature switch - -A bad temperature
switch could cause an inoperative clutch or input problems
Exam Questions and Answers
Cooling system leak diagnosis - -Pressure test or dye test
- Purpose of a radiator - -The purpose of the radiator is to dissipate heat
that is picked up by coolant in the engine into the air passing through its fins
and tubes
- Symptoms of low coolant - -Engine overheating and no heat from the
HVAC system
- Purpose of the thermostat - -The purpose of the thermostat is to trap the
coolant in the engine until it reaches it operating temperature
- Cause of low heater output - -Low coolant level, clogged heater core,
leaking heater core
- Heater core hose routing - -The supply hose from the heater core should
run from the closed side of the thermostat to the heater core and the return
hose should run from the heater core to the engine
- Heater core operation - -The blower motor blows air through the heater
core fins and is warmed through the principle of conduction
- Heater control valve purpose - -This valve controls the flow of the coolant
to the heater core to control the temperature of the air desired by the
operator
- Radiator cap testing - -To test pressure test it using an adapter and a
coolant pressure tester and the value marked on the pressure cap
- Reciever drier purpose - -May contain a filter or strainer to catch and trap
foreign particles and dirt
- Reciever drier location - -Located on the high side of the system between
the condenser and the evaporator
- Ambient temperature switch purpose - -Monitors temperature by
increasing or decreasing with resistance as temperature changes
- Symptoms of a failing ambient temperature switch - -A bad temperature
switch could cause an inoperative clutch or input problems
