How to Identify Expansion Valve Failure?

[DelAshley]

Methods to determine if the expansion valve is faulty are as follows: 1. Connect the refrigerant gauge to the low-pressure and high-pressure pipes respectively. 2. Start the car and turn on the air conditioning. Under normal circumstances, when accelerating, the low-pressure decreases while the high-pressure increases. 3. If the expansion valve is blocked, when accelerating, the high-pressure rises very quickly, the low-pressure does not drop, and the air conditioning does not produce cool air. 4. The high-pressure pipe should not be touched. Both the high-pressure pipe and the inlet pipe of the evaporator have sight glasses, which show a small amount of bubbles when accelerating. 5. Dense bubbles indicate insufficient refrigerant; excessive bubbles indicate too much refrigerant.