Preventive Maintenance
Engine Oil Fundamentals
Oil Change Procedures
Fluids & Filters
Shop Maintenance Decisions
100

What is preventive maintenance?

Routine service performed to help prevent problems and keep a vehicle operating properly.

100

What is the primary purpose of engine oil?

To lubricate moving engine components and reduce friction and wear.

100

What component removes contaminants from circulating engine oil?

The engine oil filter.

100

What fluid is used in a vehicle's windshield washer reservoir?

Windshield washer fluid.

100

Where should used engine oil be placed after an oil change in our shop?

In the designated waste-oil collection tank.

200

 What two measurements are commonly used to determine when scheduled vehicle maintenance is due?

Mileage and time.

200

What does the W stand for in an oil viscosity rating such as 5W-30?

Winter.

200

What tool should be used to tighten an oil drain plug to the manufacturer's specified torque when a torque specification applies?

A torque wrench.

200

What is the purpose of an engine air filter?

To remove airborne contaminants from the air entering the engine.

200

Why is it important to verify the correct oil filter part number before installation?

Different engines require filters with specific fitment, sealing, and operating characteristics.

300

What service information system do we use in class to find manufacturer maintenance schedules and specifications?

ALLDATA.

300

In SAE 5W-30 engine oil, what does the 30 indicate?

The oil's high-temperature SAE viscosity grade.

300

What problem can occur if the old spin-on oil filter gasket remains stuck to the engine when a new filter is installed?

A double-gasket condition that can cause a major oil leak and potentially severe engine damage.

300

Why should a technician never remove a radiator or pressurized coolant cap while the cooling system is hot?

Hot coolant and steam can escape under pressure and cause serious burns.

300

A vehicle has no transmission fluid dipstick. What should the technician do before attempting to check the fluid level?

Consult the manufacturer's service information for the correct inspection procedure.

400

Why might two identical vehicles require different maintenance intervals?

Different driving conditions, operating environments, or severe-service requirements may affect their maintenance schedules.

400

What is the difference between an engine oil's viscosity grade and its performance specification?

Viscosity describes the oil's flow characteristics under specified test conditions, while the performance specification identifies requirements the oil must meet for engine protection and operation.

400

Why should a technician check the engine oil level after filling the engine instead of relying only on the published oil capacity?

The published capacity is a starting reference; the technician must verify the actual oil level using the manufacturer's procedure to avoid underfilling or overfilling.

400

What is the difference between an engine air filter and a cabin air filter?

The engine air filter cleans air entering the engine, while the cabin air filter cleans air entering the passenger compartment through the ventilation system.

400

A technician discovers a cracked coolant hose during a routine maintenance inspection. What should the technician do?

Document the condition, notify the instructor or supervising technician, and obtain authorization before performing additional repairs.

500

 A customer requests an oil change because their vehicle has reached 3,000 miles since its last service. The manufacturer recommends a longer interval. What should the technician do?

Check the manufacturer's maintenance schedule and applicable operating conditions, explain the recommendation to the customer, and perform the service according to the customer's authorized request.

500

A vehicle requires SAE 0W-20 oil meeting a specific manufacturer approval. The shop has SAE 0W-20 oil that does not meet that approval and SAE 5W-30 oil that does. Which should the technician use?

 Neither should automatically be used. The technician should obtain oil that meets both the required viscosity and manufacturer specification, unless the manufacturer explicitly permits an alternative.

500

After completing an oil change, the technician starts the engine and notices oil leaking from the filter area. What should happen next?

Shut off the engine promptly, investigate and correct the leak, verify the oil level, and recheck for leaks before returning the vehicle to service.

500

During a fluid inspection, a technician notices that the brake fluid level is low. Why shouldn't the technician automatically top it off without further inspection?

The level may be affected by brake pad wear or a leak. The cause should be investigated before adding fluid or recommending repairs.

500

A technician finishes an oil change but forgets to reinstall the oil filler cap. What problems could this cause, and what should have prevented the mistake?

Oil may splash or escape, contaminants may enter, and some engines may develop operating problems. A systematic final inspection and verification checklist should have caught the missing cap.