Air conditioner blows hot air. 1995 Mercedes-Benz E300
The air conditioner in my car is only blowing hot air. I have had to take it to the shop many times for this same A/C problem and no one seems to know how to fix it. It is usually in the hot temperatures when the air conditioner stops blowing cold air; however, when it is cooler temperatures outside it will blow cold air. Could you please tell me what is causing this so I can get it fixed? Thanks.
Experienced mechanics share their insights in answering this question :
Hi there, thanks for writing in about your 1995 Mercedes-Benz E550. This could be a variety of issues, such as no pressure or low refrigerant levels, a bad compressor clutch, or a compressor not engaging correctly. Check to see if the cooling fans are on when the AC is running. Most systems are designed to have them run when the AC is on. Also, check to be sure the compressor is engaged. Look to see if the pulley is spinning when the car is running with the AC on. If you need help with this, a qualified professional from YourMechanic can come to your car’s location to inspect the AC system and pinpoint the necessary repair.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
A car A/C blowing hot air is often the result of a refrigerant leak. Refrigerant is a liquid that circulates through your car`s A/C system, expanding and contracting as it removes heat and humidity from the cabin. None of the other A/C components will function correctly without proper refrigerant levels.
Low refrigerant pressure can cause the left side to blow warmer air than the right side, but in no case will low pressure cause the air on one side to be warmer than the outside air. Your problem is that the left side heater is stuck on.
The most likely reason your AC isn`t cooling is your car`s AC started leaking. Your car`s AC system uses freon to lower the ambient air temperature and creates needed cold air. Whenever there is a freon leak on your car there is no way to cool the air.
Why is my C300 A/C blowing hot air? If your car`s air conditioning isn`t blowing cold air at all (or it tries, then turns warm), you could have a clogged expansion valve, a faulty compressor clutch, a leak, or a malfunctioning fuse in the system.
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.
It is the job of the AC actuator to control the opening and closing of the airflow in response to the thermostat, thus controlling air movement and allowing cool air to blow down the ducts and into the house. The AC actuator is located above or below the coil. It can be set to either single speed or variable speed.
The most common reasons a Mercedes-Benz E350 ac isn`t working are a refrigerant leak, an electrical climate control issue, or a problem with the air conditioning compressor. You may not realize there`s a refrigerant leak until the air conditioner stops blowing cold.
Common Reasons AC Doesn`t Run Cold
The most common causes of broken air conditioning leaks or compression issues. If you are feeling cool — but not cold — air, the issue could be a clogged filter, a problem with the cooling fan, signs of radiator trouble, or it could simply mean it`s time to recharge your AC.
Mercedes-Benz is recalling 4227 A-Class models from model years 2018 to 2019 due to condensation potentially interfering with systems. Mercedes-Benz is recalling 2018-19 A-Class models due to an incorrectly-installed part in the air-conditioning system.
empty and usually boastful talk.
The cooling system is one where air bubbles can be a significant concern. They can lead to hot spots in the engine, which can cause it to overheat and lead to all sorts of internal engine damage that will be costly to repair. First of all, it`s important to get your cooling system inspected at least once a year.
Freon, or coolant, is the chemical in the air conditioning system that cools the air. If the system is leaking, then this chemical will eventually run out. Today`s A/C systems are more sensitive than the older ones. The air conditioner will not work properly if there is not enough of this chemical.
Mode Door Actuators: The mode door actuator controls what vents have air flow, i.e. floor, panel or front, defrost, or any combination of those. Recirculation Door Actuators: The recirculation door actuator controls the intake of air into the system, either bringing outside air in or using inside air in recirculation.
The blend door actuator in your car is actually a miniature HVAC motor that works in concert with your car`s temperature sensors to operate its climate control system. Any time you turn the dial to send out warm or cool air, the signal passes through the blend door actuator.
Typically, vehicles have 3 or 4 actuators. Vehicles with rear controlled HVAC will often have additional actuators to control the auxiliary unit, bringing the total per vehicle to as many as 6. DID YOU KNOW?
The most common symptom of the A/C Actuator going bad or when the Blend Door is stuck is when you feel inconsistent air flow coming in. The desired air you want whether it be hot or cold, is being diverted incorrectly, so you are not getting a consistent temperature out of the A/C system.
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.
One of the most common causes of a Mercedes-Benz car heater blowing cold air is a low coolant level. The coolant is responsible for keeping the engine at a stable temperature, and if the level is too low, the engine can overheat and the heater will blow cold air.
The most common causes of broken air conditioning are leaks or compressor issues. If your air is blowing cool but not cold, the problem could be a clogged filter, cooling fan problem, radiator trouble, or it could simply be that you need to recharge your AC.
If your air handler is running but not blowing air, there are two likely scenarios; either a broken AC blower belt or an issue with the motor itself. If the air handler is humming or buzzing, but not making the mechanical sounds of a motor running, you`re most likely talking about an issue with the motor itself.
One of the most common problems that Mercedes A-Class owners may experience is electrical issues. These can manifest in a variety of ways, such as dashboard warning lights, faulty sensors, or problems with the car`s infotainment system.
It houses a temperature-sensitive valve which opens and closes based off coolant temperature. Its main function is to act as the temperature regulator of your car`s cooling system. It does this by blocking the flow of coolant to the radiator until the engine has warmed up.
A car A/C blowing hot air is often the result of a refrigerant leak. Refrigerant is a liquid that circulates through your car`s A/C system, expanding and contracting as it removes heat and humidity from the cabin. None of the other A/C components will function correctly without proper refrigerant levels.
Look for it first around on the exterior of your machine, especially along the bottom edge near the ground. An AC`s reset button is typically red and visible, so it should be easy to spot. If you don`t see a reset button on the outside, it could be located inside the unit behind the service panel.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Air conditioner blows hot air. 1995 Mercedes-Benz E300
ANSWER : Hi there, thanks for writing in about your 1995 Mercedes-Benz E550. This could be a variety of issues, such as no pressure or low refrigerant levels, a bad compressor clutch, or a compressor not engaging correctly. Check to see if the cooling fans are on when the AC is running. Most systems are designed to have them run when the AC is on. Also, check to be sure the compressor is engaged. Look to see if the pulley is spinning when the car is running with the AC on. If you need help with this, a qualified professional from YourMechanic can come to your car’s location to inspect the AC system and pinpoint the necessary repair.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
While driving defroster set to hot blows hot air as it should, while idling it is blowing cold air.
ANSWER : First, the coolant level should be checked to make sure the radiator is full. While the overflow tank may be full, the radiator cap must be taken off to check the level inside the radiator. If you find the level is very low, you have a coolant leak that must be fixed. If coolant levels are normal, an engine thermostat or heater control problem may be what you’re experiencing. Consider hiring an experienced technician like one from YourMechanic who can come out and take a closer look at your lack of heat concern to offer a more personal diagnosis.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
When idling, car overheats and A/C blows hot air – 2001 Saturn L100
ANSWER : Hello. The most likely cause of the issue that your are having would be a faulty cooling fan. The cooling fans purpose is to keep the radiator and condenser for the air conditioning cool during the idling function of the vehicle.
If the cooling fan is not working, this will cause the radiator and condenser to get very hot. When the radiator and condenser get hot, this can cause the vehicle to overheat and the air conditioning not to work. When the vehicle is driving at higher speeds, the force of air that is created towards the vehicle will flow through the radiator and condenser and therefore keep them cool. I would recommend having the cooling fan checked to make sure that it is working properly. If not, I would recommend having the cooling fan replaced.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
Air conditioner blowing warm air. Heat blowing warm air. Neither hot or cold
ANSWER : If the A/C system is full and pressures are reading correctly, and the cooling system is in proper working order (thermostat opens, no overheating, etc.), then most likely the problem lies with the dash. The climate control head unit may be at fault. One or more blend doors behind the dash may be stuck or broken. If you’re unable to fix this issue yourself, consider YourMechanic, as one of our mobile technician can come diagnose the issue with your A/C firsthand and help you fix it accordingly.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
Hot air mixed with cold blows from air conditioning
ANSWER : Hey there. You will most likely have to have a mechanic bypass the heater coolant lines to have this resolved. Your A/C may not be controlling the air flow inside the evaporator correctly out of the vents and may be the blend door actuator stuck in the heat position. Have the AC system diagnosed first before bypassing the heater.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
air conditioner started making loud screeching noise and started only blowing hot air, then the noise stopped but still only blows
ANSWER : The noise is possibly from a failed compressor clutch or the compressor itself is faulty. Another possibility is the pulley bearing on the front of the compressor has failed. The issue should be fairly evident to the inspecting mechanic after some simple tests. To resolve this, the recommended diagnostic is an a/c system inspection. 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 … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
Air conditioner blowing hot air. Then fan was running low then sped up to high.
ANSWER : Hi there. It sounds like you have a low refrigerant charge; your AC system has a low charge. This is usually caused by a leak in the system. This low state of charge can cause insufficient cooling, thus the hot or cool air and not cold air is coming out of the vents. The fan running low then speeding up is normal as the AC system is being used; the high speed fan is what cools the refrigerant in the system. I believe you may have a leak in your AC system that needs to be checked. YourMechanic has several qualified technicians that can perform an AC system inspection to properly diagnose the concern at the comfort of your home or office.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
My air is blowing cold-hot-cold-hot-cold-hot…
ANSWER : It is possible that you have a leak in the AC system. There are pressure switches that will turn off the compressor if the pressure is too high or too low. The low refrigerant level could cause the AC compressor to cycle on and off. If you would like to have this done, a certified technician from YourMechanic can come to your car’s location to diagnose the AC system and make the correct repair.
Read Full Q/A … : Air conditioner blows hot air. 1995 Mercedes-Benz E300
