8.1 A pressure drop occurred during a cooling system pressure test - NSC Mechanical Technology Automotive - Question 8 - 2021 - Paper 1
Question 8
8.1 A pressure drop occurred during a cooling system pressure test. The table below shows possible causes and corrective measures. Complete the table below by writin... show full transcript
Worked Solution & Example Answer:8.1 A pressure drop occurred during a cooling system pressure test - NSC Mechanical Technology Automotive - Question 8 - 2021 - Paper 1
Step 1
Leaking water hose
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
8.1.1 Repair or replace water hose or clamp.
Step 2
Corroded Welch plug or core plug
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
8.1.2 Cylinder head gasket blown / Cylinder head warped.
Step 3
Pressure released at lower pressure than specified for the radiator cap
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
8.1.4 Replace radiator cap with suitable replacement.
Step 4
State TWO functions of the radiator cap.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Regulates the pressure in the cooling system.
Allows coolant to return to the radiator from the expansion tank.
Step 5
High carbon monoxide (CO) reading
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Too rich mixture.
Ignition misfire.
Step 6
High nitrogen oxide (NO₂) reading
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Lean fuel mixture.
Improper spark advance.
Step 7
High oxygen (O₂) reading
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Too lean air-fuel ratio.
Vacuum leaks.
Step 8
State THREE safety requirements when setting up the oil tester.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Ensure the tester can read the expected pressures of the engine.
Clean the sender unit area before fitting the tester.
Ensure that the rubber hoses of the tester are not perished.
Step 9
State FOUR manufacturer's specifications for fuel pressure test.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Fuel pressure (suction) before the fuel pump.
Fuel pump delivery pressure (after the fuel pump).
Fuel-line pressure at idle speed.
Fuel-line pressure at high revolutions.
Step 10
Remove the high-tension leads
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The ignition system will be disabled to prevent electrical shock.
Step 11
Open the throttle fully
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To ensure maximum amount of air enters the cylinder and to obtain a correct reading.
Step 12
Recording the readings
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To compare to the specifications reading and note the differences in readings between the cylinders.
Step 13
Component in the engine faulty due to increased compression
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
