ASE A1 oefentoets (motoren)
De vragen van de test blijven in het Engels.
Dit is een gratis oefenset van 15 vragen over ASE A1, motorrevisie, geschreven door het StudyPDF-team. Hij behandelt algemene motordiagnose, de cilinderkop en het klepmechanisme, het motorblok, en de smering- en koelsystemen, met meerkeuzevragen, selecteer alles wat van toepassing is en invulvragen door elkaar. Beantwoord alle 15 vragen, bekijk daarna je score en lees de uitleg bij elke vraag.
A compression test shows one cylinder much lower than the rest. A small amount of engine oil is squirted into that cylinder and the test is repeated. The reading comes up close to the others. What does this indicate?
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1. A compression test shows one cylinder much lower than the rest. A small amount of engine oil is squirted into that cylinder and the test is repeated. The reading comes up close to the others. What does this indicate?
- A. A burned exhaust valve
- B. A cracked cylinder head
- C. Worn piston rings or a worn cylinder wall
- D. A head gasket leaking between two cylinders
Toon antwoord en uitleg
Antwoord: C. Worn piston rings or a worn cylinder wall
The oil temporarily seals the gap between the rings and the bore, so if the reading jumps, the compression was escaping past the rings. If the reading does not change, the leak is somewhere oil cannot seal, which points at a valve, the head gasket or a crack. Adding the oil is what turns a dry compression test into a wet one, and it is the fastest way to split ring problems from valve problems.
2. During a cylinder leakage test, with the cylinder at top dead center on the compression stroke, air is heard hissing from the tailpipe. Which fault does this point to?
- A. Worn piston rings
- B. A leaking intake valve
- C. A leaking head gasket
- D. A leaking exhaust valve
Toon antwoord en uitleg
Antwoord: D. A leaking exhaust valve
A leakage test tells you where the air goes, and each escape route names a part. Out of the tailpipe means the exhaust valve is not sealing. Out of the throttle body or intake means the intake valve. Out of the oil fill or dipstick tube means the rings, because the air reached the crankcase. Bubbles in the radiator or a rising coolant level means the head gasket or a crack. What counts as acceptable leakage varies, so compare against the manufacturer's spec rather than a number you remember.
3. Complete the sentence.
A cylinder bore is measured with a dial bore gauge just below the ring ridge and again at the bottom of ring travel. The difference between those two readings is the cylinder's _____.
Opties voor invulveld 1: clearance, out of round, taper, runout
Toon antwoord en uitleg
Antwoord: taper
Taper is the change in bore diameter from top to bottom. It forms because the top of the ring travel sees the highest pressure, the most heat and the least lubrication, so the bore wears fastest there. Out of round is a different measurement: two diameters taken at the same depth, ninety degrees apart. Both are checked against spec before you decide whether a block can be honed or has to be bored oversize.
4. Which findings would support a diagnosis of a failed head gasket?
Selecteer alles wat van toepassing is.
- A. A steady drop in oil pressure that only happens at cold start
- B. White exhaust smoke with a sweet smell that does not clear once the engine is warm
- C. A whine from the accessory drive belt that rises with engine speed
- D. Bubbles rising steadily in the radiator with the cap off and the engine running
- E. Coolant loss with no external leak anywhere on the engine
Toon antwoord en uitleg
Antwoord: B. White exhaust smoke with a sweet smell that does not clear once the engine is warm, D. Bubbles rising steadily in the radiator with the cap off and the engine running, E. Coolant loss with no external leak anywhere on the engine
A failed head gasket lets things cross between passages that should stay separate. Coolant reaching a combustion chamber burns and leaves white steam that smells sweet and keeps coming after warm up, unlike ordinary condensation, which clears. Combustion gas pushed the other way shows as bubbles in the radiator or as pressure in the cooling system. Coolant that disappears with nothing on the ground is the classic internal leak. Belt noise and a cold start oil pressure dip are unrelated systems.
5. An engine puffs blue smoke for a few seconds right after a cold start and again after a long idle at a stoplight, then runs clean. What is the most likely cause?
- A. Worn valve stem seals or worn valve guides
- B. Worn main bearings
- C. A thermostat stuck open
- D. A restricted air filter
Toon antwoord en uitleg
Antwoord: A. Worn valve stem seals or worn valve guides
Blue smoke is burning oil, and the timing tells you how it got into the chamber. While the engine sits or idles, oil seeps down the valve stems past worn seals or loose guides and pools in the port, then burns off in a puff when the engine is started or the throttle opens. Worn rings smoke differently: the smoke is more or less constant and gets worse under load, not just at start up.
6. A technician lays a strip of Plastigage across a rod journal, installs and torques the cap, then removes the cap and compares the crushed width to the scale on the package. What is being measured?
- A. Crankshaft endplay
- B. Bearing oil clearance
- C. Connecting rod side clearance
- D. Cylinder bore taper
Toon antwoord en uitleg
Antwoord: B. Bearing oil clearance
The strip crushes to the width of the gap between the bearing and the journal, so the scale reads oil clearance directly. Do not turn the crankshaft while the strip is in place, because that smears it and ruins the reading. Endplay is measured with a dial indicator while the crank is pried fore and aft, and rod side clearance with a feeler gauge between the rod and the crank cheek. If the crushed strip is noticeably wider at one end, suspect a tapered journal and confirm it with a micrometer.
7. Complete the sentence.
The radiator cap holds the cooling system under pressure, which raises the coolant's _____. That is why a cap which no longer holds its rated pressure can let an engine boil over even when the temperature gauge looks normal.
Opties voor invulveld 1: boiling point, freezing point, specific gravity, flow rate
Toon antwoord en uitleg
Antwoord: boiling point
Pressure raises the temperature at which a liquid boils, so a sealed system can run hotter without forming steam pockets. The cap also has a second, smaller valve that lets coolant flow back from the recovery tank as the engine cools, and a cap that fails that way collapses hoses instead. Test the cap with a pressure tester and compare it to the rating stamped on it.
8. A vehicle takes far too long to warm up, the temperature gauge stays below normal, and the heater blows cool air on the highway. What is the most likely cause?
- A. A failed water pump impeller
- B. A thermostat stuck closed
- C. A collapsed lower radiator hose
- D. A thermostat stuck open
Toon antwoord en uitleg
Antwoord: D. A thermostat stuck open
The thermostat blocks flow to the radiator until the engine reaches operating temperature. Stuck open, coolant circulates through the radiator all the time, so the engine never gets fully warm and there is little heat left for the heater core. Stuck closed does the opposite and overheats the engine quickly. On most vehicles the engine computer notices a coolant temperature that never reaches the expected range and sets a code, which is a useful confirmation.
9. A compression test finds one cylinder low while all the others read normal. Which of these could produce that result?
Selecteer alles wat van toepassing is.
- A. A burned or badly seated exhaust valve
- B. A hole or a crack in that piston
- C. A clogged fuel injector on that cylinder
- D. A weak ignition coil on that cylinder
- E. Valve clearance set too tight, holding a valve slightly open
Toon antwoord en uitleg
Antwoord: A. A burned or badly seated exhaust valve, B. A hole or a crack in that piston, E. Valve clearance set too tight, holding a valve slightly open
A compression test is purely mechanical. It asks one question: can this cylinder seal and hold pressure. Anything that leaves a path for the pressure to escape shows up, including a valve that will not seat, a damaged piston and valve lash so tight that the valve never fully closes. Fuel and spark faults cause a misfire with perfectly normal compression, which is exactly why the test is useful for separating the two. Note that a valve held off its seat also cannot dump its heat into the seat, which is how tight lash eventually burns a valve.
10. How is a cylinder head checked for warpage?
- A. With a precision straightedge and a feeler gauge, checked lengthwise, across the width and along both diagonals
- B. With a dial bore gauge run along the length of the head
- C. With an outside micrometer at each corner of the head
- D. By torquing the head bolts in sequence and watching for movement
Toon antwoord en uitleg
Antwoord: A. With a precision straightedge and a feeler gauge, checked lengthwise, across the width and along both diagonals
The straightedge lies on the deck surface and the feeler gauge finds any gap under it. Checking several directions matters because heads rarely warp evenly. An aluminum head that has overheated usually humps in the middle, and that bow only shows up on the lengthwise and diagonal checks. Compare the largest gap you find against the manufacturer's limit to decide between resurfacing and replacement, and check the block deck the same way while the head is off.
11. An engine has a deep knock that is loudest under load and gets noticeably quieter when the ignition or the injector for one cylinder is disabled. What does that point to?
- A. A sticking hydraulic lifter
- B. A loose accessory drive pulley
- C. An exhaust manifold leak
- D. A worn connecting rod bearing on that cylinder
Toon antwoord en uitleg
Antwoord: D. A worn connecting rod bearing on that cylinder
Cutting the cylinder removes the combustion pressure that drives the rod down onto a worn bearing, so the knock softens or disappears. That change is the whole point of the test, because it names the cylinder as well as the fault. Lifter noise is a lighter tap from the top of the engine that does not respond to cutting a cylinder, and an exhaust leak is a tick that is loudest cold and quiets as the metal expands.
12. Complete the sentence.
Crankshaft endplay is measured with a _____ while the crankshaft is pried back and forth, and piston ring end gap is measured with a _____ after the ring is squared in the bore.
Opties voor invulveld 1: dial indicator, torque wrench, vacuum gauge, dial bore gauge
Opties voor invulveld 2: micrometer, feeler gauge, depth gauge, straightedge
Toon antwoord en uitleg
Antwoord: dial indicator, feeler gauge
Endplay is the crankshaft's fore and aft movement, controlled by the thrust bearing, and a dial indicator on the end of the crank reads it while you push the crank each way. Ring end gap is the space between the two ends of a ring sitting in the bore, and a feeler gauge slides into that space. Square the ring first by pushing it down with an inverted piston, because a cocked ring gives a false reading. Too little gap and the ring ends butt together as they heat up.
13. An engine with a rubber timing belt is in for belt replacement at the recommended interval. Which practices are correct?
Selecteer alles wat van toepassing is.
- A. Pry the belt onto the sprockets with a screwdriver so it seats fully
- B. Line up the camshaft and crankshaft timing marks before the old belt comes off, then confirm them with the new belt installed
- C. Inspect or replace the tensioner and the idler pulleys while the belt is off
- D. Turn the engine over by hand through two full crankshaft revolutions and recheck the marks before starting it
- E. Reuse the old belt if it has no visible cracks
Toon antwoord en uitleg
Antwoord: B. Line up the camshaft and crankshaft timing marks before the old belt comes off, then confirm them with the new belt installed, C. Inspect or replace the tensioner and the idler pulleys while the belt is off, D. Turn the engine over by hand through two full crankshaft revolutions and recheck the marks before starting it
On an interference engine a belt that is one tooth off, or a belt that fails, lets a piston hit an open valve, so the marks get verified twice and the engine is turned by hand first. Two crankshaft revolutions equal one camshaft revolution, which is why two turns brings every mark back around. The tensioner and idlers wear on the same clock as the belt and are the usual reason a fresh belt fails early, and many of these engines drive the water pump off the same belt, so it is replaced at the same time. Prying with a screwdriver damages the belt cords, and a belt with no visible cracks can still be at the end of its service life.
14. The oil pressure warning light comes on at idle on a high mileage engine. What should the technician do first?
- A. Replace the oil pump
- B. Switch to a much heavier oil viscosity to raise the reading
- C. Check the oil level and condition, then connect a mechanical gauge to verify the actual pressure
- D. Replace the main and rod bearings
Toon antwoord en uitleg
Antwoord: C. Check the oil level and condition, then connect a mechanical gauge to verify the actual pressure
The warning light is driven by a sender, and a failed sender or its wiring can light the lamp with pressure that is perfectly fine. Verify with a mechanical gauge at the engine speed and temperature the manufacturer specifies before you condemn a part. Low oil level, oil thinned by fuel, a clogged pickup screen, a worn pump and worn bearings all look identical from the dash, and they need different repairs. Switching to a heavier oil raises the number without fixing anything.
15. A vacuum gauge is connected to the intake manifold of an idling engine. The needle drops sharply at regular, repeating intervals and returns each time. What does that pattern suggest?
- A. A restricted exhaust system
- B. A leaking or burned valve
- C. A rich fuel mixture
- D. A worn oil pump
Toon antwoord en uitleg
Antwoord: B. A leaking or burned valve
A regular repeating drop means the same cylinder fails the same way on every cycle, which is what a valve that will not seal looks like. Random, irregular drops point instead at a sticking valve or an intermittent misfire. A reading that is low but steady points at late valve timing or a stretched timing chain, and a reading that starts normal then slowly falls as engine speed is held up is the classic sign of a restricted exhaust. The oil pump has no effect on manifold vacuum.
Wat ASE A1 motorrevisie behandelt
A1 is de toets motorrevisie in de A-serie van certificeringstoetsen voor personenauto's van het Amerikaanse National Institute for Automotive Service Excellence. De content outline valt uiteen in vier gebieden: algemene motordiagnose, diagnose en reparatie van cilinderkop en klepmechanisme, diagnose en reparatie van het motorblok, en diagnose en reparatie van de smering- en koelsystemen. Algemene motordiagnose levert van de vier de meeste vragen, en dat vertelt je waar de toets zijn gewicht legt.
Die weging is het bruikbare deel. A1 is niet in de eerste plaats een toets of je op papier een motor kunt reviseren. Het is een toets of je een klacht kunt aannemen, de juiste meting kunt kiezen en het resultaat goed kunt lezen. Compressie- en cilinderlekkagetests, oliedrukmetingen, het afpersen van het koelsysteem, geluidsdiagnose en meten met een rei, een micrometer of een meetklok komen steeds terug, want elk daarvan is een stap in een diagnose en geen feit om op te dreunen.
Voor de certificering zelf zijn twee dingen nodig. Je slaagt voor de toets, en je toont twee jaar relevante praktijkervaring aan, al kan relevante scholing een deel daarvan vervangen. Certificering duurt ook niet eeuwig. Hij verloopt en je legt de toets opnieuw af om hem geldig te houden. De inschrijfperiodes, wat een toets kost en hoe hij wordt gescoord worden allemaal door ASE bepaald en veranderen in de loop van de tijd, dus kijk de actuele gegevens na op de website van ASE en vertrouw geen getal dat je op een studiepagina leest, deze inbegrepen.
Hoe je deze oefentoets gebruikt
Deze 15 vragen blijven binnen motorrevisie en leunen op het redeneren en niet op het benoemen. Ze vragen wat een natte compressietest aantoont wat een droge niet aantoont, waar de lucht heen gaat tijdens een lekkagetest en wat elke ontsnappingsroute betekent, wat taps en onrondheid eigenlijk meten, en waarom een monteur de oliedruk met een mechanische meter controleert voordat hij aan een pomp begint. Dat is het denkwerk dat A1 beloont.
Maak hem in een keer zonder aantekeningen en lees daarna de uitleg bij elke vraag, ook bij de vragen die je goed had. Behandel een fout antwoord als een onderwerp en niet als een feit. Miste je de vraag over de lekkagetest en de vraag over de koppakking, herhaal dan de afdichting van de cilinder als een onderwerp, want die twee zijn hetzelfde idee vanuit twee richtingen benaderd.
Combineer het met tijd aan een echte motor. Lezen over het haaks zetten van een zuigerveer in de cilinderboring is niet hetzelfde als het doen, en de meetvragen op A1 gaan ervan uit dat je het gereedschap in handen hebt gehad. De verwante oefensets hieronder gaan over de bredere A-serie en over de A5 remmentoets, dus maak alle drie als je naar meer dan een certificering toewerkt.
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Je hoeft niets te uploaden om te beginnen. Heb je geen bestand bij de hand, noem dan een onderwerp, bijvoorbeeld cilinderlekkagetests of slijtage van het klepmechanisme, en Bo schrijft daar een oefentoets over. Beginnen is gratis.
Geschreven door het StudyPDF-team. Laatst bijgewerkt op 2026-08-19.