Air conditioner blowing hot air. Then fan was running low then sped up to high.
Hi there. This morning while driving to work, the air conditioner in my car was blowing hot air. Then as I neared work the fan suddenly dropped in speed then immediately sped up again. On my way home it was still blowing hot air. I left to go to auto zone, (who were no help at all) and while I was parked there after getting gas and turning off the car, all of a sudden the air started blowing cool; not cold, but cool. Of course. It's been doing this off and on very sporadically lately. I live in AZ and it is still in the high 90's. I appreciate any help you can give me. Thanks i
Experienced mechanics share their insights in answering this question :
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.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
A Failing Expansion Valve. If your A/C flip-flops from hot to cold and back again, your expansion valve could be failing. The expansion valve removes pressure from liquid refrigerant to allow expansion from a liquid to a vapor state in the evaporator.
Three of the most common reasons why HVAC systems overheat are clogged air filters, refrigerant leaks, and dirty condenser coils. These issues force your heater or air conditioner to work harder to produce the temperature and quality of airflow you need, which results in the system overheating.
If your A/C is blowing warm air, there`s a good chance your car is low on refrigerant. Simply adding refrigerant to the system isn`t enough! You`ll want to have the whole system pressure tested by the experts, so they can locate and patch any leaks before recharging the system with the right amount of refrigerant.
One of the most common reasons your car AC is blowing hot air is because of a refrigerant issue—specifically, a loss of refrigerant. This loss of refrigerant can occur either due to a leak or because your car`s refrigerant levels are too low.
If your air conditioner only stays on for a few minutes at a time and shuts off before it has a chance to cool your home, this is called short-cycling. The issue is relativity common and can have a range of causes, from a clogged air filter to an oversized system.
The hissing noise is due to the A/C evaporator being starved of enough refrigerant. You will need to have refrigerant and dye added to the system and the hissing will go away. Then use a leak dye light (black light) and check to see where a leak is and fix as required.
My Car AC Is Not Working Correctly
The most likely reason the AC isn`t working is your car`s AC is leaking. Your car`s AC unit needs freon to cool the ambient air temperature and creates needed cold air. When there is a freon leak on your car there is no way to cool the air.
If the a/c isn`t blowing cold air when the car is idling, this is an indication that there may be a problem with the AC system high pressure hose. It is also possible that there is a problem with the AC compressor.
Locate the compressor and check that the outer pulley and inner hub are turning to signify that the clutch is engaged. If not, this may be the result of a wiring problem, a bad fuse, a broken A/C switch, or low refrigerant. Note the level of cooling as well.
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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.
Check to see that the cooling fans on the condenser or radiator are running when the air –conditioning is on. Look for any restrictions like leaves, bugs or dirt that would keep air from passing over the condenser. Check the cabin air filter to ensure that it is not clogged.
Refrigerant
If you notice that the vents are blowing warm air, turn off the AC immediately because the coil will only continue to get warmer as the fan blows. If the refrigerant levels are too low, it most likely means the refrigerant lines are leaking. Refrigerant levels will never change unless there`s a leak.
Refrigerant
If you notice that the vents are blowing warm air, turn off the AC immediately because the coil will only continue to get warmer as the fan blows. If the refrigerant levels are too low, it most likely means the refrigerant lines are leaking. Refrigerant levels will never change unless there`s a leak.
Your AC is blowing warm air because while the fan is operating, something is shutting down the cooling mechanism. Causes include simple things like thermostat settings and poor air flow, but also could be issues that can spell big trouble, like electrical problems and refrigerant leaks.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
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.
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.
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.
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.
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.
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.
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.
Air conditioner blows hot air on the left side and cold air on the right side
ANSWER : A common issue across many makes and models with dual AC in the temperature blend door actuator failing and causing drastic temperature differences between the driver and passengers sides. Have the HVAC system inspected by an experienced professional to find the specific cause. A certified professional from YourMechanic can come to your car’s location to diagnose the AC and assist with proper repairs.
