Engine Repair (A1)Question 4 of 120
On an overhead-cam engine, excessive valve lash (clearance) most commonly produces which symptom?
a.Blue exhaust smoke
b.Loss of coolant
c.Low oil pressure
d.A clicking or tapping noise from the valvetrain
Explanation
Too much clearance in the valvetrain lets components hammer against one another, producing a rhythmic tapping that changes with engine speed. Insufficient lash, by contrast, can hold valves open and burn them. Proper adjustment restores quiet operation and correct valve timing.
Practice all 120 questions free — no signup required.
Related questions on this topic
- A cylinder head is warped beyond specification. Which service is normally required to restore a flat sealing surface?
- Technician A says a blown head gasket can allow coolant to enter a cylinder and cause white exhaust smoke. Technician B says it can cause bubbles in the coolant recovery tank from combustion gases. Who is correct?
- A valve that fails to seat fully will most directly cause which condition?
- Technician A says the PCV system routes crankcase blow-by vapors into the intake to be burned. Technician B says a stuck PCV valve can cause rough idle or oil leaks. Who is correct?
- A mechanic measures cylinder taper by comparing bore diameter at the top of ring travel to the bottom. This measurement is taken with a:
- Technician A says low oil pressure only at idle on a high-mileage engine can be caused by worn bearing clearances. Technician B says a worn oil pump or diluted oil can also lower pressure. Who is correct?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against ASE Automobile Certification Series (A1–A8) · How we review