Engine Fundamentals Midterm

A late model vehicle's coolant is being tested. The refractometer reading shows a freezing point of _______.

-14 degrees Fahrenheit

When the spindle contacts the anvil on a standard 0-1" English micrometer, it should read which of these values in inches?

0.000

Normal oil pump pressure in an engine is ______ PSI.

10-60

The pressure measured in the exhaust system should not be more than _______ PSI.

2.5

Engine cranking vacuum should be ________.

2.5" in. Hg. or higher

A good engine should produce how much compression during a running (dynamic) compression test at idle?

60-90 PSI

One cycle of an automotive four-stroke cycle engine completes a cycle every _______.

720 degrees

The upper radiator hose collapses when the engine cools. What is most likely the cause?

A defective pressure cap

The use of a coolant recovery machine is helpful in preventing _________ from entering the cooling system.

Air

The purpose of the oil filter bypass valve is to __________.

Allow oil to bypass the filter if the filter becomes clogged

The oil pan has ________ to keep the oil inlet submerged in oil at all times.

Baffles

Which of these smoke types indicates excessive fuel being burned in the combustion chamber?

Black

Which of these smoke types indicates oil being burned in the combustion chamber?

Blue

Lower than specified oil pressure is measured on a high-mileage engine. Tech A says that worn main or rod bearings could be the cause. Tech B says that a clogged oil pump pickup screen could be the cause.

Both

Tech A says that a telescopic gauge is used with a micrometer to measure the inside of a hole or bore, such as the big end of a connecting rod or cylinder bore. Tech B says that a camshaft bearing surface and lobe can be measured using a micrometer.

Both

Tech A says that an engine's size is called displacement and represents the volume displaced or swept by all the pistons in one cycle. Tech B says that the engine power is expressed in horsepower and based on the amount of torque or twisting force the engine produces.

Both

Tech A says that the paper test could detect a burned valve. Tech B says that a grayish white stain on the engine could be a coolant leak.

Both

Tech A says that the radiator should always be inspected for leaks and proper flow before installing a rebuilt engine. Tech B says that overheating during slow city driving can be caused by a defective electric cooling fan.

Both

Technician A says that the lubricating system forms a seal between the piston rings and cylinder walls. Tech B says the lubricating system helps cool engine parts.

Both

Two technicians are discussing oil pumps. Tech A says that many oil pumps are driven directly off the front of the crankshaft. Tech B says that some are driven from the distributor if the engine uses a distributor-type ignition system.

Both

Two technicians are discussing testing coolant proper pH. Tech A says that coolant has a pH above 7 when new and becomes lower with use in an engine. Tech B says that OAT and HOAT coolants have a lower pH when new compared to the old green IAT coolant.

Both

Two techs are discussing oil leaks. Tech A says that an oil leak can be found using a fluorescent dye in the oil with a black light to check for leaks. Tech B says a white spray powder can be used to locate oil leaks.

Both

The marks on the head of the bolt indicate ____________.

Both grade and tensile strength

What type of pump is a water pump?

Centrifugal pump

The volume in the cylinder above the piston when the piston of the stroke (BDC) compared to the volume of the cylinder above the piston when the piston is at the top of the stroke (TDC) is referred to as ________.

Compression ratio

An engine oil cooler uses what to cool the oil.

Coolant

What can be done to prevent air from getting trapped in the cooling system when the coolant is replaced?

Coolant flush machine or open bleeder valves

Which of these components determines the engine stroke?

Crankshaft

A restricted exhaust system will cause manifold vacuum to __________ as pressure in the exhaust system ________.

Decreases;increases

Which of these tools is best to measure valve lift?

Dial indicator

Which measuring gauge needs to be set up (adjusted) to a fixed dimension before use?

Dial-bore gauge

Which of these may be used to restore damaged threads on a bolt?

Die

A smoothly operating engine depends on ______________.

Equal compression between cylinders

Which type of washer is used to provide even clamping force?

Flat washer

Oil ____ is controlled by using a windage tray in the oil pan.

Foaming

As the percentage of antifreeze in the coolant increases, ________.

Freeze point decreases

A good reading for a leakage test would be _____________.

Less than 20%

A normal reading when testing coolant for galvanic activity is ____________.

Less than 200mV

A normal reading when testing electrolysis in the coolant is ___________.

Less than 300mV

The oil pressure relief valve controls ______ oil pressure in the lubrication system.

Maximum

A telescopic gauge can be used to measure a cylinder bore if what other measuring device is used to measure the telescopic gauge?

Micrometer

The engine oil life monitor may be based on __________.

Mileage or PCM programmed algorithm

Many oils are identified by two numbers (i.e. 10W-30). These types of oil are referred to as ____________ oils.

Multi-grade

Tech A says that the cooling system should be tested for leaks using a pressure-operated pressure pump. Tech B says the freezing and boiling point of the coolant can be tested using a thermometer.

Neither

A skewed thermostat means it is ______.

Not opening at the correct temperature

A gasoline direct-injection engine has a light ticking sound when running. What should the tech do to correct the noise?

Nothing, the noise is normal

How many rotations of the crankshaft are required to complete each stroke of a four-stroke cycle engine?

One-half

What DTC could be set if the thermostat is defective?

P0128

Electric cooling fans are typically commanded on and off by the ________.

PCM

A crankshaft-driven oil pump usually has the oil pump built as part of what component?

Part of the engine front cover (aka timing cover)

Torque is expressed in units of ________.

Pound-feet

To check a crankshaft journal for out-of-round, the journal should be measured in at least how many locations?

Six

To directly measure the diameter of a valve guide in a cylinder head, use a micrometer and a _________.

Small-hole gauge

A thermostat can fail in which way?

Stuck open, closed, or partially open. (ALL OF THE ABOVE)

The most commonly used tap is a _________.

Tapered tap

Tech A says that a small-hole gauge (aka split-ball gauge) is used with a micrometer to measure small holes such as the inside diameter of a valve guide. Tech B says that a dial caliper is used to measure the inside diameter of a piston.

Tech A

Tech A says that power is the rate of doing work. Tech B says that as horsepower increases, the time required to do work increases.

Tech A

Tech A says that the crankshaft determines the stroke of an engine. Tech B says that the length of the connecting rod determines the stroke of an engine.

Tech A

Tech A says that the four strokes of the 4-stroke cycle are intake, compression, power, and exhaust. Tech B says most engines rotate clockwise as viewed from the rear (flywheel) end of the engine.

Tech A

A customer complains that the heater works sometimes, but sometimes only cold air comes out when driving. Tech A says that the water pump is defective. Tech B says that the cooling system could be low on coolant.

Tech B

A vehicle's oil pressure warning light is on. Tech A says that the pressure sending unit should be replaced and the vehicle rechecked. Tech B says that a mechanical oil pressure gauge should be used to check the oil pressure before replacing the sending unit.

Tech B

A voltmeter was used to check the coolant and a reading of 0.2 volt with the engine off was measured. A reading of 0.8 volt was measured with the engine running and all electrical accessories turned on. Technician A says that the coolant should be flushed to solve the galvanic activity. Technician B says that the ground wires and connections should be inspected and repaired to solve the electrolysis problem. Which technician is correct?

Tech B

Tech A says that an automotive water pump is a positive displacement-type pump. Tech B says that the coolant mix should be a 50/50 mix between antifreeze and water.

Tech B

Tech A says that during a power balance test, the cylinder that causes the biggest RPM drop is the weak cylinder. Tech B says that if one spark plug wire is grounded out and the engine speed does not drop, a weak or dead cylinder is indicated.

Tech B

Tech A says that engine oil should meet the vehicle manufacturer's standards. Tech B says that the specified viscosity of oil should be used.

Tech B

Tech A uses a steel gasket scraper on aluminum engine parts. Tech B uses a plastic or wood scraper on aluminum engine parts.

Tech B

Two technicians are discussing oil filters. Tech A says that the oil will remain perfectly clean if just the oil filter is changed regularly. Tech B says that oil filters can filter particles smaller than the human eye can see.

Tech B

When replacing a timing belt, many experts and vehicle manufacturers recommend that what other part(s) should be replaced?

Tensioner assembly, water pump, camshaft oil seal(s) (All of the above)

The coolant flow through the radiator is controlled by the ________.

Thermostat

The threaded movable part that rotates on a micrometer is called the __________.

Thimble

A replacement plastic intake manifold may have different design or appearance from the original factory installed part.

True

Coolant leaking from an intake manifold can evaporate fast enough to leave no trace of a leak.

True

Using the wrong oil when changing oil could cause the "Check engine" light to come on.

True

An SOHC V8 engine has how many camshafts?

Two

To check a crankshaft journal for taper, the journal should be measured in at least how many locations?

Two

In typical engine lubrication systems, what components are the last to receive oil and the first to suffer from a lack of oil or oil pressure?

Valve train

The "W" in SAE 5W-20 means ________.

Winter

Testing for galvanic activity is done with the coolant _______ and the engine _________.

cold; not running

PHOAT coolant is what color?

dark green

An intake manifold gasket has been replaced due to a vacuum leak. Which of the following steps uses a scan tool to complete the job?

idle relearn

The torque specification for many plastic intake manifolds are in what unit?

in.lbs. or lb.in.

Metric thread pitch is measured in _______.

millimeters

The number of threads per inch is referred to as ______.

pitch

The grade of a fastener, such as a bolt, is a measure of its ________.

tensile strength

The pH of coolant is tested using a ________.

test strip

On some engines equipped with a timing belt, the belt may also drive the _______.

water pump