Leak down quiz.

What is the first step if a cylinder's compression test results are out of specs?

• Perform a leak down test

• Replace the cylinder

• Check the spark plugs

• Consult the shop manual

What does a leak down test measure?

• The temperature of the engine

• The efficiency of the spark plugs

• The percentage of air escaping from the combustion chamber

• The pressure of the fuel pump

At what engine condition should the leak down test be performed?

• At operating temperature

• After the engine has been running for an hour

• When the engine is cold

• Immediately after turning off the engine

What is the correct position of the piston when performing a leak down test?

• Bottom dead center of the compression stroke

• Top dead center of the compression stroke

• Midway through the intake stroke

• At the beginning of the exhaust stroke

What indicates an engine in excellent condition based on leakage percentage?

• Zero to fifteen percent

• Forty-one percent and higher

• Sixteen to twenty-five percent

• Twenty-six to forty percent

What could be indicated by air bubbles coming out of the coolant tank during a leak down test?

• Leaking intake valves

• A cracked cylinder head or engine block

• Worn spark plugs

• Faulty fuel injectors

What tool is suggested to use for listening to air leaks?

• A dial indicator

• A mechanic's stethoscope

• An OBD scanner

• A torque wrench

What does white exhaust smoke out of the tailpipe indicate?

• A clogged air filter

• Faulty spark plugs

• A leak to the cooling system

• Damaged or worn piston rings

What should you do if you suspect an excessive leak to the crankcase?

• Replace the crankshaft

• Add a teaspoon of engine oil through the spark plug hole and perform the test again

• Clean the fuel injectors

• Replace the engine coolant

What can cause the valves to leak, as mentioned in the text?

• Carbon deposits or a damaged valve seat

• Low engine oil levels

• Faulty timing belt

• Defective exhaust manifold