What are the hazards of idling a diesel vehicle with the air conditioning on for a long time?
2 Answers
Idling with the air conditioning on for extended periods increases fuel consumption and leads to carbon buildup in the engine, while also placing significant stress on the cooling system. Prolonged idling with the AC running can cause the air inside the vehicle to become stale. If the vehicle is parked in a poorly ventilated area, it may lead to carbon monoxide poisoning inside the cabin. Precautions for using car air conditioning are as follows: 1. Turn off the AC switch: Before parking and turning off the engine, first switch off the AC (cooling function), set the blower to maximum speed, and activate the external circulation for 3-5 minutes to dry the evaporator and air filter, eliminating temperature differences with the external environment. This prevents condensation caused by temperature differentials, which can lead to mold growth in the AC evaporator pipes. 2. Keep the AC dry: After rainy or humid weather, run the AC on sunny days to maintain dryness. Extended periods of damp weather significantly affect the AC system. After sunny weather returns, use external circulation and turn on the blower to dry it out, preventing mold. 3. Adjust airflow: Occasionally run the AC at high speed. If the AC remains unused for long periods, dirt or dust can accumulate in the ducts, eventually leading to mold growth. This not only causes unpleasant odors but also releases harmful air. Therefore, regularly running the AC at high speed helps maintain cleanliness in the system.
I've been driving trucks for over 20 years, and nothing frustrates me more than seeing drivers idle with the AC on while sleeping. Diesel engines don't burn fuel completely at low speeds—black smoke pours from the exhaust, and carbon builds up in the throttle body at an alarming rate. Last month, I worked on a truck where the piston rings were stuck due to carbon deposits; when we opened up the engine, it was full of sludge. Plus, the alternator output isn't enough, so the battery drains constantly—replacing a new battery costs 800 bucks. The cooling system is even worse: the fan is inefficient when stationary, and the temperature gauge keeps hitting the red zone. A few rounds of this, and the head gasket is guaranteed to fail. That's why I always tell my crew—if you're parked for more than 20 minutes, shut off the engine.
