Last Updated on November 2, 2022
Decades ago, having an air conditioning system in your car was considered a luxury. Today, it’s a basic feature that we often take for granted.
You want the air conditioner to work efficiently and effectively every time you use it. If any one of the parts in the A/C system fails, the air conditioning won’t work well, if it even works at all.
The air conditioner condenser is a critical component of this air-cooling and air-drying process. With a bad A/C condenser, you won’t be a very happy person in the middle of summer. Here’s how this part works and what signs you should look for to diagnose a faulty air conditioner condenser.
How Does an A/C Condenser Work?
Air conditioners, both in cars and in the home, work on the basis of heat exchange and pressure gradients. In the car, a substance called refrigerant (or freon) is converted from liquid to gas and back again in a nearly closed system of which the A/C condenser is a very important part.
Pressure gradients are required in order for this to work correctly, so any leaks in the system will eventually cause failure.
The A/C compressor, driven by the crankshaft of the car, pressurizes gaseous refrigerant. This is the point in the cycle at which the A/C system changes from low pressure to high pressure.
Next, this high-pressure refrigerant flows to the A/C condenser, which is like a small radiator at the front of the car where heat is removed from the refrigerant by being transferred to the outside air flowing over it. This causes the gas to condense back into a liquid. The A/C condenser is therefore the key to removing heat from the system.
This cooled liquid moves to the receiver-drier/accumulator which removes excess moisture and any debris from the liquid.
The refrigerant then travels to the expansion valve or orifice tube, which are small openings to allow only a bit of liquid through at a time. This relieves pressure on the substance, which brings us back to the low pressure side of the system.
The evaporator, located under the dashboard on the passenger side in most cases, is the next stop for this very cool low-pressure liquid. The refrigerant makes its way through the evaporator while an A/C blower fan moves cabin air through it.
The refrigerant absorbs the heat (causing the liquid to boil and turn back into a gas) from the air, which cools the air before it blows through the dash into the cabin.
The warmed gaseous refrigerant then flows back to the A/C compressor to repeat this process.
See Also: 8 Reasons Your A/C Compressor Clutch Won’t Engage
5 Symptoms of a Bad A/C Condenser
While a few of these problems just indicate a problem with something in the air conditioning system, those that relate to a buildup of heat usually point to the A/C condenser since removing the system of heat is its main job.
#1 – Lukewarm Air From Vents
This is probably the first thing you will notice if your A/C condenser is failing. When you expect cool air and are hit with a lukewarm gust instead, the A/C condenser should be inspected for blockages or defects which cause restrictions in airflow.
If the flow of the gas and liquid are interrupted here then the entire system is unable to run at its maximum efficiency.
Related: 8 Common Causes of No Cold Air From A/C
#2 – Burning Smell
When the vehicle can’t release the heat the A/C system builds up, then eventually the temperature of all of the parts will increase to the point that components start burning and emitting a smell while the A/C is turned on.
This is a serious problem and you will likely need to replace multiple parts of the system as they may be melted so badly that they no longer function.
#3 – Overheating While Idling
For the same reasons, a vehicle that isn’t circulating refrigerant through the A/C condenser successfully won’t eliminate heat well so it will build up in the system.
Normally, the A/C condenser is cooled by the air flow it receives once the vehicle starts moving again, but if too much heat is built up by a faulty condenser then this normal behavior just won’t be enough cooling.
#4 – Noticeable Coolant Leaks
As the A/C condenser contains refrigerant under high pressure, it is more prone to leaks if there are any vulnerabilities in the part.
Leaks due to failing seals is a normal part of the aging of the condenser, but the entire part should be replaced before all of the refrigerant leaks out of the system.
#5 – Warning Lights on Dashboard
Some newer vehicles have a warning system that detects a problem with the air conditioning system and emits a warning light on the dashboard. Check your owner’s manual to see if this is something that you should watch for.
Causes of a Bad A/C Condenser
The main cause of a failing A/C condenser is simple wear and tear of the seals and tubes in the part caused by aging. Unfortunately, since the seals alone cannot be replaced, the entire condenser unit must be replaced.
Another cause of a faulty condenser is debris inside that either blocks the flow of refrigerant or travels in the refrigerant and causes damage as it contacts the A/C system components.
These debris often come from a broken A/C compressor that releases metallic fragments into the system. If this is the problem, both the A/C compressor and A/C condenser will need replacement.
If moisture gets into the system via leaks in the seals, ice crystals can form and cause similar blockages and mechanical damage as the metallic pieces.
Air Conditioner Condenser Replacement Cost
The cost of replacing an A/C condenser varies based on the type of vehicle and whether or not other parts in the A/C system need repairs or replacement as well. In most vehicles it should cost between $400 and $900 to replace the condenser, with about $200 to $400 of this going towards labor and the remainder for parts.
It’s not recommended for a home mechanic to try to replace the A/C condenser as this can be a dangerous job due to the high-pressure properties of the system and because specific tools are needed.
For example, the refrigerant which will be released when the system is opened must be contained with specialized recovery equipment as it is illegal to vent it into the atmosphere.
It’s a good idea to periodically clean the A/C condenser to preserve the life of the unit. You can either do it yourself following some simple online video tutorials or take it in to a mechanic for maintenance, either option will still be cheaper than replacing the condenser completely if it’s still working well.
Other parts in the A/C system, such as vents, cabin air filter, and the A/C condenser fan, should also be cleaned regularly for maximum efficiency.
- 9 Best Car Buffers and Polishers (Use What the Pros Use) - February 24, 2023
- Spark Plug Socket Sizes (w/ Chart) - January 19, 2023
- AWD vs 4WD (Is There a Difference?) - July 15, 2022
16 thoughts on “5 Symptoms of a Bad Car A/C Condenser (and Replacement Cost)”
My car has been smelling a little different from AC for the last few days. After reading your article, I am sure that it is due to some problem of car AC condenser. Does your AC Unit make slight humming noises? Your condenser unit has a run relay in it that may be causing your slight hum noise. The low voltage control transformer in the furnace also powers the Run relay in the condenser. Try turning off the furnace power either by a local switch by the furnace or the breaker. Then check the hum. If it is gone you may have a bad thermostat. It could be causing some AC voltage leaking thru it causing it to hum but not enough voltage to pull in the relay turning on the condenser.
I have changed the cabin filter, put a new condenser as the gas was cleaking out as it was pretty poor condition, on the pump clutch engages without a problem and turns as it should after second gas refill to manufacturers spec, its still not cold, the pipes coming from the pump arent cold like i would think they would…. only thing i can think of is changing the switch that sits on the condenser but Im sure that only turns the pump on or off which is happening anyway… anything else anyone can think of… its a low31000 miles Astra 1.8 sri.
I have had a leak (2005 Buick Century)supposedly fixed. Only blows cool for about 2 weeks when wires (?) are manuvered. I am told it is the condenser. It blows very nicely. Help. Thank you.
In the old days having A/C (Air Conditioning System) in a vehicle was considered a luxury. But in the modern era, it is a basic facility that every auto manufacture gives with their vehicle to customers. The condenser in the air conditioner is a very vital component in the process of air-drying and air-cooling. If something bad happens to the condenser of the air conditioner then it will not work effectively, especially in the summer season.
You have really done well, your explanation is so comprehensive and I’m able to learn a lot from it. More grease to your elbow brother.
My AC cools better when the car is moving fast, but when it’s on idle it’s almost warm air flowing out of the cabin vents, could this be a problem with condenser not being efficient enough ?
Ac was blowing warmer air and mechanic said it was the compressor, $1;000 later still blowing warm air. Too the car back in they said it’s the condenser, replace that at a $1,000. I pick up car on Monday hopefully it’s fixed. Can they tell if the problem from the AC unit is the condenser or compressor in the beginning of diagnosing it?
I have the same problem. It could be a clogged and/or dirty condenser. It could also be poor airflow (fans) or low refrigerant. That’s pretty much all it could be if it’s cold while driving. Too much oil or air in the system will have the same effect as low refrigerant and the condenser won’t dissipate heat as well. If the low side pressure looks normal and the high side pressure is too high, it’s probably condenser related.
Maybe, but I would check the freon. If the driver side vents are cold and passenger side vents are warm or not as cold your low on freon. I had this issue already.
Would a partially blocked condenser cause the vents to blow two different temperatures? I’ve already checked all the blend actuators and they are functioning as intended. The only other symptom is that the low pressure side of the system sees a significant pressure spike when the compressor engages. I didnt note the exact pressures involved, but the gauge shot into the red every time the compressor would run and as soon as it did the compressor would disengage. I assume to protect the system. I already assume I’ll need to have the whole thing professionally diagnosed and repaired, but before I ever set foot into a shop I like to be armed with as much information as possible.
my car ac is not cooling 100%, I noticed that the discharge line was so hot but the condenser was cool not getting hot. We flushes many times and its good no blackage. the high and low pressure was within the range. note this ac system was converted ,not original compressor and condenser. what could the problem?
Thanks in advance
Are you sure the system has no leaks? I would check for leaks before going further.
Hi. I purchased a 2011 honda accord last August 2019. The air was never cold enough, but I , never really use ac at all much anyways, so I didnt think anything of it. Just recently in the last month I started turning it on and keeping it on for longer periods of time. At this point it was clear.. the ac was not blowing cold. I figured it just needed freon. One morning, I noticed water condensation on the inside of every window. And the overhead fabric was peeling off in one spot. The car smelled like damp socks were left in there overnight. I brought it to the dealership, and was told the condenser is leaking and the evaporator is clogged. The repairs are over 1k and the car is only worth about 8k. It has only been 8 months since I got this vehicle, so, is it possible that this can happen in such a short period of time with minimal use? Or is it possible that the dealership never checked , but should have done so, before selling the car because the figured the problem wouldn’t arise for another couple months, at which point it wouldn’t be there problem anymore?
It’s hard to say if the dealership was trying to pull a fast one on you. Most dealerships I’ve been to are only concerned with getting a new car to look good before selling it. Unless it’s a CPO car, usually it’s up to the customer to notice and point out the flaws. Mechanical issues discovered can often be worked into the deal, as the dealership should fix them at no cost to you in order to make the sale.
this is the complete information of the car ac condenser. This information will help us to know when to replace the condenser of ar ac. Thanks for the amazing information.
Well explain thank you so much.