Your car is overheating when AC-On and Engine idle. Reasons and Solutions?

  • Whatsapp
car is overheating when idling and ac-on

Air conditioning (AC) is sophisticated and driven by a crankshaft pulley. The refrigerant flows via pipes, changing states. The cabin air is cooled and dehumidified.

Note: A mechanic will presume that “overheating” means the engine is too hot. Some say AC vents spew heated air.

Idling with the AC on, your automobile overheats. This case is rare, but why? Your car engine overheating when idling with AC on is most caused by a broken compressor

If your AC blows hot air during idle, the compressor or pulley may fail but not break. Many more AC system faults exist.

How Does the Air Conditioning in a Car Work?

The air conditioner is not a “cold air blower” in its basic form. It consists of a pressurized network of tubes filled with a refrigerant that was developed expressly to power these kinds of systems. You may have heard of them before: R-22, R-12, R-410A, and R-32 are all previously popular but now obsolete refrigerants (or are being phased in).

Raise the hood of your vehicle. Do you notice the belt that is hooked to a few different pulleys? The drive belt also called the serpentine belt, is another name for this component. It gets its power from the camshaft in the engine, and one of these pulleys drives the air conditioning.

This is a straightforward explanation of How a Car AC works; the pulley is responsible for producing the “compression” force that is then utilized by the compressor to move the refrigerant through the system. The refrigerant takes the heat from the incoming air when it transitions between portions of high-pressure and low-pressure as well as liquid and gas states.

In addition to it, it goes via an evaporator and a condenser. These operate in a manner analogous to that of radiators. While the evaporator is responsible for removing heat and moisture from the air, the condenser is the component that is responsible for returning that heat to the environment.

How to Diagnose and Repair an Overheating Vehicle While the Air Conditioner Is Running

You must take your vehicle to a licensed mechanic to work on air conditioning systems. Sadly, the air conditioner is far too specialized for you to work on it alone at home.

To operate with automobile refrigerants, you would need an extensive collection of professional equipment, including UV lamps, a comprehensive understanding of mechanics, and a professional certification.

If they are released into the atmosphere by accident, refrigerants cause severe harm to the environment and are a significant contributor to climate change. It is, in fact, against the law.

The takeaway is that you should bring your vehicle to a qualified mechanic.

They may need to replace the compressor unit, including the clutch and the pulley. Replacing a new compressor unit could cost anything from $500 to $1,000.

Depending on the model, you should anticipate paying more than the stated amount for the component, which ranges from $200 to $400. After that, the costs of labor for installation will range between $100 and $200. Finally, the air conditioner will require re-gassing and a leak test, adding another $100 to $150 to the total cost.

Additionally, the serpentine belt has to be checked for signs of wear. It’s possible that the friction caused by the seized pulley caused it to become damaged. There is a possibility that it will need to be replaced, so plan on spending an additional $50 to $75. Since the old belt will already be removed, there shouldn’t be any further charges for labor afterward.


If the engine in your car is overheating, it is unlikely that the air conditioner is to blame. There are numerous other possibilities, the most important of which are the levels of coolant and oil, the failure of the fan, or the failure of the head gasket.

Taking your vehicle to a qualified mechanic is the most effective and reliable way to resolve the issue. If it is discovered that the air conditioner is providing resistance to the turning power of the crankshaft, it may be one of the factors that cause the engine to overheat. However, as was indicated earlier, there are almost certainly more elements at play here.

If hot air is blown into the cabin through the vents, the air conditioner is almost certainly to blame for the problem. Please take it to a professional who can diagnose and fix the problem.

It ought to be entirely risk-free for going in your vehicle. The air conditioning is not a fundamental component of the system; instead, it is a convenient add-on that may purchase separately.

Could you kindly perform a quick visual inspection of the serpentine belt? It is possible that it could snap while you are driving, causing additional damage to the engine compartment if it is badly frayed.

Related posts

Leave a Reply