C OF Q 310T MAIN EXAMINATION 2026/2027 QUESTIONS
AND SOLUTIONS RATED A+
✔✔Which category of engine oil is compatible with biofuels?
a) ASE
b) CJ-4
c) PC-11
d) API - ✔✔c) PC-11
✔✔Which governing body is responsible for affixing the oil viscosity designed
description of oil labelled such as "15W40"?
a) UTI
b) API
c) EPA
d) SAE - ✔✔d) SAE
✔✔Motor oils are typically made up of __________ chemical additives.
a) 20-30%
b) 25-45%
c) 10-15%
d) 15-25% - ✔✔d) 15-25%
✔✔Shortened oil change intervals can be expected when using a biofuel and fossil fuel
mix above ____________.
a) 20%
b) 30%
c) 15%
d) 28% - ✔✔a) 20%
✔✔Engine oil temperature should not exceed __________ degrees.
a) 280
b) 138
c) 300
d) 250 - ✔✔d) 250
✔✔Cellulose and paper oil filtering medium generally has a filtering capability between
__________ microns.
a) 15-25
b) 2-5
,c) 1-5
d) 13-20 - ✔✔d) 13-20
✔✔The EPA recommends oil filters be hot-drained for ________ hours before disposal.
a) 18
b) 8
c) 24
d) 12 - ✔✔d) 12
✔✔The oil pressure regulating valve is normally located in the outlet of the oil pump or
in the ____________.
a) engines oil cooler
b) secondary oil filter
c) main oil gallery
d) primary oil filter - ✔✔c) main oil gallery
✔✔The purpose of a centrifugal oil filter is to remove ____________.
a) soot
b) water
c) oxygen
d) All are correct - ✔✔a) soot
✔✔Oil pressure regulating valves operate by ____________.
a) engine rpm
b) oil temperature
c) centrifugal force
d) spring force - ✔✔d) spring force
✔✔Which series of engine oils are used in diesel engines?
a) C series
b) ASTM
c) S series
d) SAE - ✔✔a) C series
✔✔Which of the following is the most recent diesel engine oil classification?
a) CJ
b) SG
c) SB
, d) CA - ✔✔a) CJ
✔✔When should engine oil be changed in a diesel?
a)It depends on the distance travelled
b) It depends on the quality of the oil used
c) It depends on the number of accumulated engine hours since the last service
d) At 3-5% soot loading - ✔✔d) At 3-5% soot loading
✔✔The "15W" in 15W-40 engine oil stands for which of the following?
a) The thickness of the oil when hot
b) Multiple viscosities
c) Viscosity at 0°F (-18°C)
d) Viscosity at 212°F (100°C) - ✔✔c) Viscosity at 0°F (-18°C)
✔✔Maximum lubrication oil temperature not exceed:
a) 250°F (121°C).
b) 235°F (113°C).
c) 215°F (102°C).
d) 200°F (93°C). - ✔✔a) 250°F (121°C).
✔✔Which of the following takes place when engine oil becomes hotter?
a) Its viscosity increases and the engine may consume more oil.
b) Its viscosity increases and the oil thins.
c) Its viscosity decreases and it thickens.
d) Its viscosity decreases and oil pressure is lower at idle. - ✔✔d) Its viscosity
decreases and oil pressure is lower at idle.
✔✔When EGR systems are added to diesel engines, what oil properties need to
change?
a) The engine oil must resist higher engine operating temperatures and reduce engine
wear.
b) The oil must handle more soot and become more acidic.
c) The oil must handle more soot and become more alkaline.
d) The oil must handle less soot and become more alkaline. - ✔✔c) The oil must handle
more soot and become more alkaline.
✔✔Cartridge filters are preferred over spin-on filters because:
a) they are more environmentally friendly and often easier to access.
b) they are less expensive and the canisters are easily loosened with a wrench.
AND SOLUTIONS RATED A+
✔✔Which category of engine oil is compatible with biofuels?
a) ASE
b) CJ-4
c) PC-11
d) API - ✔✔c) PC-11
✔✔Which governing body is responsible for affixing the oil viscosity designed
description of oil labelled such as "15W40"?
a) UTI
b) API
c) EPA
d) SAE - ✔✔d) SAE
✔✔Motor oils are typically made up of __________ chemical additives.
a) 20-30%
b) 25-45%
c) 10-15%
d) 15-25% - ✔✔d) 15-25%
✔✔Shortened oil change intervals can be expected when using a biofuel and fossil fuel
mix above ____________.
a) 20%
b) 30%
c) 15%
d) 28% - ✔✔a) 20%
✔✔Engine oil temperature should not exceed __________ degrees.
a) 280
b) 138
c) 300
d) 250 - ✔✔d) 250
✔✔Cellulose and paper oil filtering medium generally has a filtering capability between
__________ microns.
a) 15-25
b) 2-5
,c) 1-5
d) 13-20 - ✔✔d) 13-20
✔✔The EPA recommends oil filters be hot-drained for ________ hours before disposal.
a) 18
b) 8
c) 24
d) 12 - ✔✔d) 12
✔✔The oil pressure regulating valve is normally located in the outlet of the oil pump or
in the ____________.
a) engines oil cooler
b) secondary oil filter
c) main oil gallery
d) primary oil filter - ✔✔c) main oil gallery
✔✔The purpose of a centrifugal oil filter is to remove ____________.
a) soot
b) water
c) oxygen
d) All are correct - ✔✔a) soot
✔✔Oil pressure regulating valves operate by ____________.
a) engine rpm
b) oil temperature
c) centrifugal force
d) spring force - ✔✔d) spring force
✔✔Which series of engine oils are used in diesel engines?
a) C series
b) ASTM
c) S series
d) SAE - ✔✔a) C series
✔✔Which of the following is the most recent diesel engine oil classification?
a) CJ
b) SG
c) SB
, d) CA - ✔✔a) CJ
✔✔When should engine oil be changed in a diesel?
a)It depends on the distance travelled
b) It depends on the quality of the oil used
c) It depends on the number of accumulated engine hours since the last service
d) At 3-5% soot loading - ✔✔d) At 3-5% soot loading
✔✔The "15W" in 15W-40 engine oil stands for which of the following?
a) The thickness of the oil when hot
b) Multiple viscosities
c) Viscosity at 0°F (-18°C)
d) Viscosity at 212°F (100°C) - ✔✔c) Viscosity at 0°F (-18°C)
✔✔Maximum lubrication oil temperature not exceed:
a) 250°F (121°C).
b) 235°F (113°C).
c) 215°F (102°C).
d) 200°F (93°C). - ✔✔a) 250°F (121°C).
✔✔Which of the following takes place when engine oil becomes hotter?
a) Its viscosity increases and the engine may consume more oil.
b) Its viscosity increases and the oil thins.
c) Its viscosity decreases and it thickens.
d) Its viscosity decreases and oil pressure is lower at idle. - ✔✔d) Its viscosity
decreases and oil pressure is lower at idle.
✔✔When EGR systems are added to diesel engines, what oil properties need to
change?
a) The engine oil must resist higher engine operating temperatures and reduce engine
wear.
b) The oil must handle more soot and become more acidic.
c) The oil must handle more soot and become more alkaline.
d) The oil must handle less soot and become more alkaline. - ✔✔c) The oil must handle
more soot and become more alkaline.
✔✔Cartridge filters are preferred over spin-on filters because:
a) they are more environmentally friendly and often easier to access.
b) they are less expensive and the canisters are easily loosened with a wrench.
