Question

if there is a vacuum pocket at the thermostat, the air pocket may prevent the thermostat from getting up to temperature and ______, potentially causing the brand new engine to overheat.
a. cooling
b. opening
c. closing
d. heating

Explanation:

A car thermostat opens to allow coolant flow for engine cooling. A vacuum/air pocket stops it from reaching operating temperature, so it fails to open, blocking coolant flow and causing overheating.

Answer:

b. Opening