ASE Certified Mechanic
Congratulations on your decision to boost and accelerate your career potential as an auto mechanic!
ASE certification is nationally recognized and will put you ahead of the competition in the auto mechanic job market!
Be sure to try our free practice tests to ensure you ace the ASE exam!
Automotive mechanic certification requirements vary from state to state, so please select your state below to read about how to quickly get certified as an auto mechanic today!
Free ASE 1 – Engine Repair Test Questions & Study Guide
Preparing for the Automotive Service Excellence (ASE) A1 – Engine Repair exam and don’t know where to start?
Test your knowledge with some free ASE tests and know where you stand! After clicking on your answer, be sure to review what the correct answer and explanation.
By using these free ASE test questions, you’ll know where to brush up on your engine repair knowledge and exactly which study guides to hone in on and follow. Be sure to check out the auto mechanic certification requirements by state for additional information!
Click Here to Continue this Test…
Heater Cores Purpose and Function
Most of the heat absorbed from the engine by the cooling system is wasted. Some of this heat, however, is recovered by the vehicle heater. Heated coolant is passed through tubes in the small core of the heater. Air is passed across the heater fins and is then sent to the passenger compartment. In some vehicles, the heater and air conditioning work in series to maintain vehicle compartment temperature.
Heater Problem Diagnosis
When the heater does not produce the desired amount of heat, many owners and technicians replace the thermostat before doing any other troubleshooting. It is true that a defective thermostat is the reason for the engine not to reach normal operating temperature, but there are many other causes besides a defective thermostat that can result in lack of heat from the heater. To determine the exact cause, follow this procedure.
A typical heater core installed in a heating, ventilation, and air-conditioning (HVAC) housing assembly.
After the engine has been operated, feel the upper radiator hose. If the engine is up to proper operating temperature, the upper radiator hose should be too hot to hold. The hose should also be pressurized.
- If the hose is not hot enough, replace the thermostat.
- If the hose is not pressurized, test or replace the radiator pressure cap if it will not hold the specified pressure.
- If okay, see step 2.
With the engine running, feel both heater hoses. (The heater should be set to the maximum heat position.) Both hoses should be too hot to hold. If both hoses are warm (not hot) or cool, check the heater control valve for proper operation (if equipped). If one hose is hot and the other (return) is just warm or cool, remove both hoses from the heater core or engine and flush the heater core with water from a garden hose.
If both heater hoses are hot and there is still a lack of heating concern, then the fault is most likely due to an airflow blend door malfunction. Check service information for the exact procedure to follow.
HINT: Heat from the heater that “comes and goes” is most likely the result of low coolant level. Usually with the engine at idle, there is enough coolant flow through the heater. At higher engine speeds, however, the lack of coolant through the heads and block prevents sufficient flow through the heater.
Cooling System Testing
Many cooling system faults can be found by performing a thorough visual inspection. Items that can be
inspected visually include:
- Water pump drive belt for tension or faults
- Cooling fan for faults
- Heater and radiator hoses for condition and leaks
- Coolant overflow or surge tank coolant level
- Evidence of coolant loss
- Radiator condition
A heavily corroded radiator from a vehicle that was overheating. A visual inspection discovered that the corrosion had eaten away many of the cooling fins, yet did not leak. This radiator was replaced and it solved the overheating problem.
Pressure testing using a hand-operated pressure tester is a quick and easy cooling system test. The radiator cap is removed (engine cold!) and the tester is attached in the place of the radiator cap. By operating the plunger on the pump, the entire cooling system is pressurized.
- CAUTION: Do not pump up the pressure beyond that specified by the vehicle manufacturer. Most systems should not be pressurized beyond 14 PSI (100 kPa). If a greater pressure is used, it may cause the water pump, radiator, heater core, or hoses to fail.
If the cooling system is free from leaks, the pressure should stay and not drop. If the pressure drops, look for evidence of leaks anywhere in the cooling system, including:
- Heater hoses
- Radiator hoses
- Heater core
- Cylinder head
- Core plugs in the side of the block or cylinder head
The pressure cap should be checked for proper operation using a pressure tester as part of the cooling system diagnosis.
Pressure testing should be performed whenever there is a leak or suspected leak. The pressure tester can also be used to test the radiator cap. An adapter is used to connect the pressure tester to the radiator cap. Replace any cap that will not hold pressure.
Pressure testing should be performed whenever there is a leak or suspected leak.
Coolant Dye Leak Testing
One of the best methods to check for a coolant leak is to use a fluorescent dye in the coolant, one that is specifically designed for coolant. Operate the vehicle with the dye in the coolant until the engine reaches normal operating temperature. Use a black light to inspect all areas of the cooling system. When there is a leak, it will be easy to spot because the dye in the coolant will be seen as bright green. Pressure testing the cooling system. A typical hand-operated pressure tester applies pressure equal to the radiator cap pressure. The pressure should hold; if it drops, this indicates a leak somewhere in the cooling system. An adapter is used to attach the pump to the cap to determine if the radiator can hold pressure, and release it when pressure rises above its maximum rated pressure setting.
Use dye specifically made for coolant when checking for leaks using a black light.
Next Steps towards ASE Certification
Now that you’re familiar with Heater Cores: Problem Diagnosis, Inspection, Pressure, and Dye Testing, try out our free Automotive Service Excellence Tests to see how much you know!
Types of Systems
Coolant flows through the engine in one of the following ways.
- Parallel flow system. In the parallel flow system, coolant flows into the block under pressure and then crosses the head gasket to the head through main coolant passages beside each cylinder.
- Series flow system. In the series flow system, the coolant flows around all the cylinders on each bank. All the coolant flows to the rear of the block, where large main coolant passages allow the coolant to flow across the head gasket. The coolant then enters the rear of the heads. In the heads, the coolant flows forward to a crossover passage on the intake manifold outlet at the highest point in the engine cooling passage. This is usually located at the front of the engine. The outlet is either on the heads or in the intake manifold.
- Series-parallel flow system. Some engines use a combination of these two coolant flow systems and call it a seriesparallel flow system. Any steam that develops will go directly to the top of the radiator. In series flow systems, bleed holes or steam slits in the gasket, block, and head perform the function of letting out the steam.
A Chevrolet V-8 Block that shows the large coolant holes and the smaller gas vent or bleed holes that must match the head gasket when the engine is assembled.
Coolant Flow and Head Gasket Design
Most V-type engines use cylinder heads that are interchangeable side to side, but not all engines. Therefore, based on the design of the cooling system and flow through the engine, it is very important to double check that the cylinder head is matched to the block and that the head gasket is installed correctly (end for end) so that all of the cooling passages are open to allow the proper flow of coolant through the system.
Electronically Controlled Cooling Fan
Two types of electric cooling fans used on many engines include:
- One two-speed cooling fan
- Two cooling fans (one for normal cooling and one for high heat conditions)
The PCM commands low-speed fans on under the following conditions.
- Engine coolant temperature (ECT) exceeds approximately 223°F (106°C).
- A/C refrigerant pressure exceeds 190 PSI (1,310 kPa).
- After the vehicle is shut off, the engine coolant temperature at key-off is greater than 284°F (140°C) and system voltage is more than 12 volts. The fan(s) will stay on for approximately three minutes.
The PCM commands the high-speed fan on under the following conditions.
- Engine coolant temperature (ECT) reaches 230°F (110°C).
- A/C refrigerant pressure exceeds 240 PSI (1,655 kPa).
- Certain diagnostic trouble codes (DTCs) set.
A typical electric cooling fan assembly showing the radiator and related components.
To prevent a fan from cycling on and off excessively at idle, the fan may not turn off until the ignition switch is moved to the off position or the vehicle speed exceeds approximately 10 mph (16 km/h).
Many rear-wheel-drive vehicles and all transverse engines drive the fan with an electric motor.
- NOTE: Most electric cooling fans are computer controlled. To save energy, most cooling fans are turned off whenever the vehicle is traveling faster than 35 mph (55 km/h). The ram air caused by the vehicle speed is enough to keep the radiator cool. Of course, if the computer senses that the temperature is still too high, the computer will turn on the cooling fan, to “high,” if possible, in an attempt to cool the engine to avoid severe engine damage.
Warning: Some electric cooling fans can come on after the engine is off without warning. Always keep hands and fingers away from the cooling fan blades unless the electrical connector has been disconnected to prevent the fan from coming on. Always follow all warnings and cautions.
On some rear-wheel-drive vehicles, a thermostatic cooling fan is driven by a belt from the crankshaft. It turns faster as the engine turns faster. Generally, the engine is required to produce more power at higher speeds. Therefore, the cooling system will also transfer more heat. Increased fan speed aids in the required cooling. Engine heat also becomes critical at low engine speeds in traffic where the vehicle moves slowly. The thermostatic fan is designed so that it uses little power at high engine speeds and minimizes noise. Two types of thermostatic fans include:
- Silicone coupling. The silicone coupling fan drive is mounted between the drive pulley and the fan. HINT: When diagnosing an overheating problem, look carefully at the cooling fan. If silicone is leaking, then the fan may not be able to function correctly and should be replaced.
- Thermostatic spring. A second type of thermal fan has a thermostatic spring added to the silicone coupling fan drive. The thermostatic spring operates a valve that allows the fan to freewheel when the radiator is cold. As the radiator warms to about 150°F (65°C), the air hitting the thermostatic spring will cause the spring to change its shape. The new shape of the spring opens a valve that allows the drive to operate like the silicone coupling drive. When the engine is very cold, the fan may operate at high speeds for a short time until the drive fluid warms slightly. The silicone fluid will then flow into a reservoir to let the fan speed drop to idle.
A typical engine-driven thermostatic spring cooling fins
The fan is designed to move enough air at the lowest fan speed to cool the engine when it is at its highest coolant temperature. The fan shroud is used to increase the cooling system efficiency.
Tech Tip: Be Sure to Always Use a Fan Shroud
A fan shroud forces the fan to draw air through the radiator. If a fan shroud is not used, then air is drawn from around the fan and will reduce the airflow through the radiator. Many overheating problems are a result of not replacing the factory shroud after engine work or body repair work to the front of the vehicle.
Next Steps towards ASE Certification
Now that you’re familiar with Coolant Flow in the Engine, try out our free Automotive Service Excellence Tests to see how much you know!
The water pump (also called a coolant pump) is driven by one of two methods.
Coolant recirculates from the radiator to the engine and back to the radiator. Low-temperature coolant leaves the radiator by the bottom outlet. It is pumped into the warm engine block, where it picks up some heat. From the block, the warm coolant flows to the hot cylinder head, where it picks up more heat.
- NOTE: Some engines use reverse cooling. This means that the coolant flows from the radiator to the cylinder head(s) before flowing to the engine block.
A demonstration engine running on a stand showing the amount of coolant flow that actually occurs through the cooling system.
Frequently Asked Quesiton: How much Coolant Can a Water Pump Move?
A typical water pump can move a maximum of about 7,500 gallons (28,000 liters) of coolant per hour, or recirculate the coolant in the engine over 20 times per minute. This means that a water pump could be used to empty a typical private swimming pool in an hour! The slower the engine speed, the less power is consumed by the water pump. However, even at 35 mph (56 km/h), the typical water pump still moves about 2,000 gallons (7,500 liters) per hour or 0.5 gallon (2 liters) per second!
Water pumps are not positive displacement pumps. The water pump is a centrifugal pump that can move a large volume of coolant without increasing the pressure of the coolant. The pump pulls coolant in at the center of the impeller. Centrifugal force throws the coolant outward so that it is discharged at the impeller tips.
As engine speeds increase, more heat is produced by the engine and more cooling capacity is required. The pump impeller speed increases as the engine speed increases to provide extra coolant flow at the very time it is needed.
Coolant flow through the impeller and scroll of a coolant pump for a V-type engine
Coolant leaving the pump impeller is fed through a scroll. The scroll is a smoothly curved passage that changes the fluid flow direction with minimum loss in velocity. The scroll is connected to the front of the engine so as to direct the coolant into the engine block. On V-type engines, two outlets are often used, one for each cylinder bank. Occasionally, diverters are necessary in the water pump scroll to equalize coolant flow between the cylinder banks of a V-type engine in order to equalize the cooling.
Water Pump Service
A worn impeller on a water pump can reduce the amount of coolant flow through the engine.
If the seal of the water pump fails, coolant will leak out of the weep hole. The hole allows coolant to escape without getting trapped and forced into the water pump bearing assembly.
The hole allows coolant to escape without getting trapped and forced into the water pump bearing assembly.
If the bearing is defective, the pump will usually be noisy and will have to be replaced. Before replacing a water pump that has failed because of a loose or noisy bearing, check all of the following:
- Drive belt tension
- Bent fan
- Fan for balance
If the water pump drive belt is too tight, excessive force may be exerted against the pump bearing. If the cooling fan is bent or out of balance, the resulting vibration can damage the water pump bearing.
Tech Tip: Release the Belt Tension before Checking a Water Pump
The technician should release water pump belt tension before checking for water pump bearing looseness. To test a water pump bearing, it is normal to check the fan for movement; however, if the drive belt is tight, any looseness in the bearing will not be felt.
Next Steps towards ASE Certification
Now that you’re familiar with Water Pumps in Automotive Engine Coolant Systems, try out our free Automotive Service Excellence Tests to see how much you know!
Purpose and Function
Excess pressure usually forces some coolant from the system through an overflow. Most cooling systems connect the overflow to a plastic reservoir to hold excess coolant while the system is hot.
When the system cools, the pressure in the cooling system is reduced and a partial vacuum forms. This vacuum pulls the coolant from the plastic container back into the cooling system, keeping the system full. Because of this action, the system is called a coolant recovery system. A vacuum valve allows coolant to reenter the system as the system cools so that the radiator parts will not collapse under the partial vacuum.
The level in the coolant recovery system raises and lowers with engine temperature.
Some vehicles use a surge tank, which is located at the highest level of the cooling system and holds about 1 quart (1 liter) of coolant. A hose attaches to the bottom of the surge tank to the inlet side of the water pump. A smaller bleed hose attaches to the side of the surge tank to the highest point of the radiator. The bleed line allows some coolant circulation through the surge tank, and air in the system will rise below the radiator cap and be forced from the system if the pressure in the system exceeds the rating of the radiator cap.
Some vehicles use a surge tank, which is located at the highest level of the cooling system, with a radiator cap.
Real World Fix: The Collapsed Radiator Hose Story
An automotive student asked the automotive instructor what brand of radiator hose is the best. Not knowing exactly what to say, the instructor asked if there was a problem with the brand hose used. The student had tried three brands and all of them collapsed when the engine cooled. The instructor then explained that the vehicle needed a new pressure cap and not a new upper radiator hose. The student thought that because the lower hose did not collapse that the problem had to be a fault with the hose. The instructor then explained that the lower radiator hose has a spring inside to keep the lower hose from collapsing due to the lower pressure created at the inlet to the water pump. The radiator cap was replaced and the upper radiator hose did not collapse when the engine cooled.
Next Steps towards ASE Certification
Now that you’re familiar with Coolant Recovery Systems and Surge Tanks, try out our free Automotive Service Excellence Tests to see how much you know!
Older Entries »
Types of Radiator Cores
The two types of radiator cores in common use in most vehicles are:
- Serpentine fin core
- Plate fin core
In each of these types, the coolant flows through oval-shaped core tubes. Heat is transferred through the tube wall and soldered joint to cooling fins. The fins are exposed to the air that flows through the radiator, which removes heat from the radiator and carries it away.
The tubes and fins of the radiator core.
Since the 1980s, most radiators have been made from aluminum with nylon-reinforced plastic side tanks. These materials are corrosion resistant, have good heat transferability, and are easily formed.
Core tubes are made from 0.0045 to 0.012 in. (0.1 to 0.3 mm) sheet brass or aluminum, using the thinnest possible materials for each application. The metal is rolled into round tubes and the joints are sealed with a locking seam.
The two basic designs of radiators include:
- Down-flow radiators. This design was used mostly in older vehicles, where the coolant entered the radiator at the top and flowed downward, exiting the radiator at the bottom.
- Cross-flow radiators. Most radiators use a cross-flow design, where the coolant flows from one side of the radiator to the opposite side.
A radiator may be either a down-flow or a cross-flow type.
How Radiators Work
The main limitation of heat transfer in a cooling system is in the transfer from the radiator to the air. Heat transfers from the water to the fins as much as seven times faster than heat transfers from the fins to the air, assuming equal surface exposure. The radiator must be capable of removing an amount of heat energy approximately equal to the heat energy of the power produced by the engine. Each horsepower is equivalent to 42 BTUs (10,800 calories) per minute. As the engine power is increased, the heat-removing requirement of the cooling system is also increased.
With a given frontal area, radiator capacity may be increased by increasing the core thickness, packing more material into the same volume, or both. The radiator capacity may also be increased by placing a shroud around the fan so that more air will be pulled through the radiator.
- NOTE: The lower air dam in the front of the vehicle is used to help direct the air through the radiator. If this air dam is broken or missing, the engine may overheat, especially during highway driving due to the reduced airflow through the radiator.
When a transmission oil cooler is used in the radiator, it is placed in the outlet tank, where the coolant has the lowest temperature.
Many vehicles equipped with an automatic transmission use a transmission fluid cooler installed in one of the radiator tanks.
On most radiators the filler neck is fitted with a pressure cap. The cap has a spring-loaded valve that closes the cooling system vent. This causes cooling pressure to build up to the pressure setting of the cap. At this point, the valve will release the excess pressure to prevent system damage. Engine cooling systems are pressurized to raise the boiling temperature of the coolant.
- The boiling temperature will increase by approximately 3°F (1.6°C) for each pound of increase in pressure.
- At sea level, water will boil at 212°F (100°C). With a 15 PSI (100 kPa) pressure cap, water will boil at 257°F (125°C), which is a maximum operating temperature for an engine.
The specified coolant system temperature serves two functions.
- It allows the engine to run at an efficient temperature, close to 200°F (93°C), with no danger of boiling the coolant.
- The higher the coolant temperature, the more heat the cooling system can transfer. The heat transferred by the cooling system is proportional to the temperature difference between the coolant and the outside air. This characteristic has led to the design of small, high-pressure radiators that are capable of handling large quantities of heat. For proper cooling, the system must have the right pressure cap correctly installed.
A vacuum valve is part of the pressure cap and is used to allow coolant to flow back into the radiator when the coolant cools down and contracts.
- NOTE: The proper operation of the pressure cap is especially important at high altitudes. The boiling point of water is lowered by about 1°F for every 550 ft increase in altitude. Therefore, in Denver, Colorado (altitude 5,280 ft), the boiling point of water is about 202°F, and at the top of Pike’s Peak in Colorado (14,110 ft) water boils at 186°F.
Metric Radiator Caps
According to the SAE Handbook, all radiator caps must indicate their nominal (normal) pressure rating. Most original equipment radiator caps are rated at about 14 to 16 PSI (97 to 110 kPa).
The pressure valve maintains the system pressure and allows excess pressure to vent. The vacuum valve allows coolant to return to the system from the recovery tank.
However, many vehicles manufactured in Japan or Europe use radiator pressure indicated in a unit called a bar. One bar is the pressure of the atmosphere at sea level, or about 14.7 PSI. The conversions can be used when replacing a radiator cap, to make certain it matches the pressure rating of the original.
- NOTE: Many radiator repair shops use a 7 PSI (0.5 bar) radiator cap on a repaired radiator. A 7 PSI cap can still provide boil protection of 21°F (3°F x 7 PSI = 21°F) above the boiling point of the coolant. For example, if the boiling point of the antifreeze coolant is 223°F, then 21°F is added for the pressure cap, and boilover will not occur until about 244°F (223°F + 21°F = 244°F). Even though this lower pressure radiator cap provides some protection and will also help protect the radiator repair, the coolant can still boil before the “hot” dash warning light comes on and, therefore, should not be used. In addition, the lower pressure in the cooling system could cause cavitation to occur and damage the water pump. For best results, always follow the vehicle manufacturer’s recommended radiator cap.
Working Better Under Pressure
A problem that sometimes occurs with a high-pressure cooling system involves the water pump. For the pump to function, the inlet side of the pump must have a lower pressure than its outlet side. If inlet pressure is lowered too much, the coolant at the pump inlet can boil, producing vapor. The pump will then spin the coolant vapors and not pump coolant. This condition is called pump cavitation. Therefore, a radiator cap could be the cause of an overheating problem. A pump will not pump enough coolant if not kept under the proper pressure for preventing vaporization of the coolant.
Next Steps towards ASE Certification
Now that you’re familiar with Radiators in Automotive Engines, try out our free Automotive Service Excellence Tests to see how much you know!
Free ASE Test Questions A1-A8
Are you looking to ace the Automotive Service Excellence (ASE) A1-A8 tests on your way to becoming an ASE certified Master Mechanic?
If so, try out these free ASE test questions to build your knowledge and prepare for the exams. Choose any of the free A1-A8 tests to practice showing off your knowledge and mechanic skills for free to know where you stand! After clicking on your answer, be sure to review what the correct answer and explanation.
By practicing on these free ASE test questions, you’ll know exactly where to study up on, whether it’s transmission/transaxle, suspension & steering, or even brakes – you’ll know exactly which study guides to hone in on and follow. Be sure to check out the auto mechanic certification requirements by state for additional information!
- General Engine Diagnosis
- Cylinder Head and Valve Train Diagnosis and Repair
- Engine Block Diagnosis and Repair
- Lubrication and Cooling Systems Diagnosis and Repair
- Fuel, Electrical, Ignition, and Exhaust Systems Inspection and Service
- General Transmission/Transaxle Diagnosis (Mechanical/Hydraulic Systems, Electronic Systems)
- In-Vehicle Transmission/Transaxle Maintenance and Repair
- Off-Vehicle Transmission/Transaxle Repair (Removal and Installation, Disassembly and Assembly, Friction and Reaction Units)
- Clutch Diagnosis and Repair
- Transmission Diagnosis and Repair
- Transaxle Diagnosis and Repair
- Drive Shaft/Half-Shaft Diagnosis and Repair (Front and Rear Wheel Drive)
- Drive Axle Diagnosis and Repair
- Four-Wheel Drive/All-Wheel Drive Component Diagnosis and Repair
- Steering Systems Diagnosis and Repair (Columns, Units, Linkage)
- Suspension Systems Diagnosis and Repair (Front, Rear)
- Related Suspension and Steering Service
- Wheel Alignment Diagnosis, Adjustment, and Repair
- Wheel and Tire Diagnosis and Service
- Hydraulic, Power Assist, and Parking Brake Systems Diagnosis and Repair
- Drum Brake Diagnosis and Repair
- Disc Brake Diagnosis and Repair
- Electronic Brake Control Systems (ABS, TCS, ECS) Diagnosis and Repair
- General Electrical/Electronic System Diagnosis
- Battery and Starting System Diagnosis and Repair
- Charging System Diagnosis and Repair
- Lighting Systems Diagnosis and Repair
- Instrument Cluster and Driver Information Systems
- Body Electrical Systems Diagnosis and Repair
- A/C System Service, Diagnosis and Repair
- Refrigeration System Component Diagnosis and Repair
- Heating and Engine Cooling Systems Diagnosis and Repair
- Operating Systems and Related Controls Diagnosis and Repair
- General Engine Diagnosis
- Ignition System Diagnosis and Repair
- Fuel, Air Induction, and Exhaus Systems
- Emissions Control Systems Diagnosis and Repair
- Computerized Engine Controls Diagnosis and Repair
Secret ASE Certification Test Taking Tips!
Test taking is an acquired, learned skill in any subject or industry and it’s important that you fully acquaint yourself with the test material and format before you walk in on the big day. Hands-on experience and learning in the field is important for anyone looking to take the Automotive Service Excellence (ASE) Certification test but if you really want to excel and pass with flying colors, you have to take a more strategic approach and study the test itself!
Practice tests are fantastic because they provide you with important information about a number of factors. You’ll learn what basic testing format you should expect, some of the possible material that might be presented, and, best of all, you’ll become aware of any holes in your training and technical knowledge to address before you take the real test. These three components are of the utmost importance when preparing for a big test, especially one that can change the course of your career moving forward!
You’ll find example questions in a practice test for the ASE Certification test right here at the ASE Certification Training Headquarters. You can also take the official practice tests on the ASE website, but there is a $14.95 cost per practice test, so we highly recommend trying the free ones first. The questions are standard, relevant, and related so that you can test your knowledge and master the test on your first attempt. You might also try considering taking some technical classes before committing to the official practice test. Do you know what a moderately loose alternator belt might cause in a vehicle? Try the practice questions and test your knowledge right now!