Overheating with AC on?

When the air conditioner is on, my car overheats when i unplug the thermostat plug the engine with be cool but ac will not come on

My car has 4500000 miles.
My car has a manual transmission.

Experienced mechanics share their insights in answering this question :
Hi There,
Overheating with the AC on is generally caused by a couple of possibilities. When the AC compressor is beginning to fail, this may incur an increased load on the motor as it works harder than usual to turn a bad compressor. This increased load causes the motor to work harder than it otherwise normally would, resulting in the motor overheating. The other possibility may be a cooling system that is not working efficiently. This may be caused by a clogged radiator, blocked or clogged radiator condenser fins, a water pump that is not pumping correctly or potentially cooling fans that are not working properly.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

One of the most common reasons why your engine overheats when your AC is on is a faulty engine cooling fan, fan switch, or fan motor. A bad engine coolant sensor, an overloaded AC compressor, a broken water pump, and blocked AC condenser fins can also create overheating issues.
There`s a leak in the cooling system – Most often, a leak in the cooling system is what`s causing your car to overheat. The radiator, hoses, water pump, head gasket, and thermostat housing are all components of the cooling system, and all can be susceptible to leaks.
The air conditioner can cause an engine to overheat quickly because it makes the engine work harder. Even though it`s hot outside, if you turn off the AC, you may be able to avoid overheating, especially if you take the next step, which we apologize for in advance.
Can a Bad AC Compressor Cause My Car to Overheat? The compressor itself cannot cause the vehicle to get overheated. However, if the compressor clutch is engaged but the compressor is dragging to function properly, the extra strain on the engine can cause your car to overheat.
Another symptom that may present itself when the fan has failed is the vehicle overheating while the engine is idling with the AC on. During the conversion process, the AC condenser is able to generate a considerable amount of heat, which can affect the overall engine temperature enough to cause overheating.
Turn Off the Air Conditioner

It may seem counterintuitive, but when you`re trying to prevent overheating, it may help to turn off your car`s air conditioner. The energy required to power the AC can overload your engine. Then, it can exacerbate an overheating problem.

In general, it`s because something`s wrong within the cooling system and heat isn`t able to escape the engine compartment. The source of the issue could include a cooling system leak, faulty radiator fan, broken water pump, or clogged coolant hose.
Circuit Breaker Tripping

If the outside condensing unit consistently loses power and trips a circuit breaker, it may mean that the compressor is about to fail. It`s a sign that the compressor is overheating and needs too much power to do its job.

If the thermostat`s batteries are worn out, running low on power, or corroding, they can cause your thermostat to act up. Low batteries are the most common (and easiest) issue to fix, so start there.
If you overcharge your car`s air conditioner, you could do some serious damage to your car`s compressor, put increased strain on your engine, and even cause overheating.
If the air filter is clogged, air circulation suffers, the AC struggles to cool the house, and the AC may overheat. The solution is to clean or replace the air filters regularly. Apart from air filters, vents and registers also contribute to proper air circulation.
Replacing the capacitor and/or fan blade with the correct one should solve the problem. Poor airflow. Not having the fan blades installed in a correct position can result in a lack of airflow and cause the motor to overheat.
Temperatures Above 100 Degrees Fahrenheit

Most air conditioning systems are designed to function with outside temperatures of 100 degrees or less. When temperatures outside become higher than 100 degrees Fahrenheit, the air conditioning system can consume more energy and begin to malfunction or fail.

How long can a car overheat before damage occurs? It only takes 30-60 seconds of overheating for permanent damage to infiltrate a vehicle. As soon as you notice signs of overheating, you need to act. Failure to do so might result in troubles like coolant leaks, damaged radiator caps, and a faulty cooling fan.
Technically speaking yes you can use plain water in your cooling system but it isn`t recommended as a long term solution and certainly not in extreme weather conditions.
Your overheated engine may still be running, but it`s not fine. You risk costly damage to your engine if you keep driving. DON`T panic. Your engine may have lost its cool, but now is the time for you to keep yours!
Look to see if the coolant is swirling/flowing immediately — that means the thermostat`s stuck open. If the coolant doesn`t flow after 10 minutes or so and continues to be stagnant after the temperature gauge indicates it`s hot, the thermostat`s likely stuck closed. Replace the radiator cap and turn off the engine.
A bad thermostat can cause your AC to not cool or heat the room to the desired temperature. Air conditioning concerns are more apparent: Your thermostat is one of the best indicators of your air conditioning system`s health.
It`s not a good idea to drive with a broken A/C compressor. While you can sometimes drive your vehicle with a broken A/C compressor without needing expensive repairs, it`s not wise. When these integral parts of your car`s air conditioning system break, that can cause greater damage to your engine and even your health.
The short answer is that your AC compressor and refrigerant should last about 12-15 years. Learning what crucial components, and how to maintain the compressor, can keep your AC running efficiently for its entire lifespan.
The Consequences of an Overcharged Air Conditioner

One major problem is that when there`s too much refrigerant, it won`t be able to properly switch between gaseous and liquid state, and more of it will remain in liquid state. This will harm the system`s efficiency and affect cooling in the house.

An overworked unit can cause you to feel uncomfortable. It may unable to cool your room evenly. Some spots may be too warm while the others are cool. This may happen because the unit is having a problem in replacing the hot air and circulating the cool air.
Having too much refrigerant in your AC can damage the compressor. This can happen because the excess refrigerant will likely collect inside the compressor and cause subcooling, wherein temperatures are below normal. Furthermore, the extra refrigerant can flood the compressor and damage its mechanical parts.
Air compressor overheating issues are often the result of excess discharge pressure, which typically stems from one or more of the following issues: Dirty condensing coils. Ill-fitted discharge line. Blockage of condenser air.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

2008 VW Jetta AC not cold
ANSWER : Hi Allen. By far the best way to have your AC system correctly diagnosed is by having an AC inspection completed first. By having one of our professional mobile mechanics come to your location to diagnose the issue correctly, it significantly minimizes the mistakes in completing the wrong service. In your case, the issue could be as simple as needing to have the AC system recharged, or there is an existing leak that needs to be repaired before refilling the refrigerant. Best economic bet is to have the AC inspection completed first.

Read Full Q/A … : Overheating with AC on?

My 2001 Honda Accord keeps overheating
ANSWER : This can be caused by a number of things such as low coolant levels, a faulty thermostat, a clogged radiator or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. I would suggest having an expert from Your Mechanic come to your home to diagnose your cooling system.

Read Full Q/A … : Overheating with AC on?

Overheats When Blowing Warm With Heat & AC But Not When Blowing Cold AC
ANSWER : Hello, thank you for writing in. There are so many different codes being triggered, that it is unlikely all of these systems are having issues at once. We need to focus in on the fact the engine is overheating at all. You will want to check the level and condition of the coolant and the overflow tank. If the level is full then you may have an issue with the thermostat, radiator cap, or water pump. These can all be tested and changed relatively easily. If the main cooling system is okay, you will want to look into the heater core and climate control module. For more diagnostic help, contact our service department to schedule an appointment.

Read Full Q/A … : Overheating with AC on?

when I turn my ac on my cars idle drop and stalls out and the ac is hot
ANSWER : Hello, thank you for writing in. Although the pulley is still spinning, the compressor has likely failed. If it is not properly regulating pressure in the system, one of the first signs is a warm air conditioner. Considering yours is not cooling off, the pressures are not correct. If you believe the compressor is working correctly, you may want to check for a clogged line before replacing it. Keep in mind, a blocked line has likely put extra strain on the compressor, and may cause premature failure. For more help with testing or replacing the compressor, contact our service department to schedule an appointment.

Read Full Q/A … : Overheating with AC on?

Honda Civic 2008. AC stopped working suddenly and engine check light came ON for a day.Next day AC worked and no engine light.
ANSWER : Hi there. In both cases, when an AC system is not working and a warning light is coming on the dashboard, typically a professional mechanic will complete the same initial inspection, which is to download the stored error codes that triggered the warning light initially. This tends to give them an idea as to what is causing the problems. This could be something as simple as an electrical relay that is faulty or loose or an indication of a computer related "glitch". Either way, the best way to move forward is to have a professional mobile mechanic complete a check engine light inspection.

Read Full Q/A … : Overheating with AC on?

Car cabin smells of AC refrigerant at times and now the AC is not cooling after about a month of filling it .
ANSWER : If you have detected a refrigerant and oil mist in the cabin, then an evaporator "area" leak is likely. However, any time there is one leak, the entire system should be pressurized (whether pre or post repair) and tested for leaks in order to ensure trouble free operation. To request diagnosis and repair of your system, please use YourMechanic’s a/c diagnostic service page and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Read Full Q/A … : Overheating with AC on?

Low coolant light comes on when AC, defrost or heater is on, but only if the car is in gear and stopped, what’s wrong with my car?
ANSWER : First, you want to make sure your cooling system is full. Check the radiator not the coolant jug. And check it when it is cold. If it needs coolant, add some. Of course, I don’t feel this problem is an actual low coolant condition. I would expect to find an electrical failure in the instrument cluster or from a component or wiring harness that is connected to the instrument cluster.

As a technician, I have access to reports from technicians across the country. I could not find any reports of this problem, so diagnosing this will require an experienced tech as this is not a common problem. In addition, this happens at intermittent times making it difficult to recreate. The most challenging part of this diagnosis will be recreating the symptom. I suspect it has something to do with the brake switch circuitry because it only seems to happen when you have your foot on the brake. I would begin my diagnosis there with a wiring diagram and test light in hand. The brake switch, instrument cluster, and environmental controls all interact with each other. Something is crossed either because of a failed module or damaged wiring in a harness.

Aside from making sure the coolant is full, this will not likely leave you on the side of the road. If you take it in to be diagnosed, be prepared for them to spend more time than usual to figure it out. Since it isn’t a key problem, you may need to live with it until it completely fails making it much easier to diagnose. Either way, I do recommend having a certified mechanic diagnose the warning light to make sure there isn’t anything serious going on.

Good luck.

Read Full Q/A … : Overheating with AC on?

2002 oldsmobile silhouette stalls and won’t start for when I use AC, but runs fine when Ac is not used
ANSWER : Hi there. In most cases when a car will not run while the AC is on, it’s due to an existing problem with the fuel or ignition system that is simply amplified. The AC is powered by a belt driven system, which draws more power from the engine in order to operate the system. In other instances, this problem can be caused by a damaged AC compressor. Due to the multiple possible sources, it’s best to have a professional mechanic come to your location and complete a car is hard to start inspection to isolate this problem and recommend the right repairs.

Read Full Q/A … : Overheating with AC on?