Question 1
IntermediateEngine Systems · Inspect and test radiator, heater core, pressure cap, and coolant recovery system; determine needed repairs; perform cooling system pressure and dye tests.
A technician tests a radiator pressure cap using a handheld pressure pump and the correct neck adapter. The cap is stamped 16 psi (110 kPa). When pumped up to 16 psi, the pressure gauge needle immediately drops down to 10 psi within 5 seconds and holds there. What is the correct diagnosis and recommended action?
Answer and explanation
Correct answer: C
A radiator cap must hold its rated pressure without dropping. Leaking down to 10 psi indicates a defective spring or seal, requiring cap replacement.
