Engine Repair A1 Flashcards
6 cards from real ASE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Engine Repair A1 flashcards as text
A technician is measuring piston ring end gap and finds it is less than the manufacturer's specification. What is the correct action?
Answer: File the ring ends carefully to achieve the correct gap
When piston ring end gap is too small, the ring ends can butt together during engine operation causing the ring to break or score the cylinder wall. The technician should use a ring file to carefully enlarge the gap to within specification.
When pressure testing a cooling system, a technician finds the pressure drops slowly over 15 minutes with no visible external leaks. What is the most likely cause?
Answer: Internal head gasket leak
A slow pressure loss with no visible external leaks strongly indicates an internal leak, most commonly a blown head gasket allowing coolant to enter the combustion chamber or oil passages. External leaks would be visible on the ground or engine components.
A diesel engine has excessive crankcase pressure (blow-by). Which component failure is MOST likely responsible?
Answer: Worn piston rings and cylinder walls
Excessive crankcase pressure (blow-by) occurs when combustion gases bypass the piston rings and enter the crankcase. Worn piston rings and cylinder walls allow this gas passage, increasing crankcase pressure significantly.
During engine assembly, a technician checks main bearing clearance using Plastigage and finds it measures 0.001 inch. The specification is 0.0010–0.0025 inch. What should the technician do?
Answer: The clearance is acceptable; proceed with assembly
A clearance of 0.001 inch falls exactly at the minimum of the specification range of 0.0010–0.0025 inch, making it acceptable. The technician should proceed with assembly using proper torque and lubrication procedures.
A technician is replacing valve stem seals on an overhead cam engine without removing the cylinder head. What tool is needed to prevent the valves from dropping into the cylinder?
Answer: A valve spring compressor and an air hose through the spark plug hole
When replacing valve stem seals in-vehicle, compressed air is introduced through the spark plug hole to hold the valves against their seats while the valve springs are removed. A valve spring compressor is also required to compress the springs and remove the keepers.
An engine produces a loud knocking noise that increases with RPM and load. The noise is most pronounced on the power stroke. What is the MOST likely cause?
Answer: Worn connecting rod bearings
A rod knock is a heavy metallic knock that occurs on the power stroke and increases with engine speed and load. The worn connecting rod bearing allows excessive crankshaft-to-rod play, creating an impact as combustion force drives the piston down.