Auto A/C Compressors have evolved over time and the old, fixed displacement compressor has been replaced by more efficient variable displacement compressors. Pressure controlled variable displacement compressor and Electronically Controlled Variable Displacement Compressor (ECV) react in different ways compared to fixed displacement compressors when air conditioning restrictions and other common automotive a/c faults happen. Failure to identify the type of a/c compressor in the vehicle at the beginning of the diagnostic procedure could lead to unnecessary, expensive and in most cases time consuming repairs. A restricted Thermal Expansion Valve creates Manifold gauge readings that could lead to chasing a/c system leaks, unnecessary auto a/c compressor and sensor replacement.
How do I know if my compressor or expansion valve is bad?
Manifold Gauge readings
Low side LOW High side LOW
A restricted Thermal Expansion valve gauge readings will be different in the newer Pressure controlled variable displacement air conditioning compressor.
When a restriction in the refrigerant flow caused by a Thermal Expansion Valve (TXV) fault happens, the Pressure controlled variable displacement compressor will try to compensate the change in refrigerant pressure from the TXV by adjusting the compressor internal control valve, and keep the compressor crankcase pressure at a value where the swash plate angle based on the low side pressure is prevented from going into the condition where you see a manifold gauge vacuum reading. The manifold gauge reading in this type of system will show Low side gauge reading low and High side gauge reading low. It could be erroneously diagnosed as a weak compressor problem.
Low Side into Vacuum High Side LOW
A restricted Thermal Expansion Valve (TXV) gauge reading on an Electronically Controlled Variable Displacement Compressor will be different due to the logic the Powertrain Control Module uses to operate and control the a/c compressor. The PCM will receive inputs from the evaporator temperature and will command signals to the ac compressor electronic control valve to adjust pumping capacity accordingly. When the TXV fails or is restricted the evaporator temperature will increase and that increase value will be sent to the PCM which in turns will increase compressor pumping capacity to 100%.The Electronically Controlled Variable Displacement Compressor will operate similar to an old ,Fixed Displacement A/C Compressor and the Manifold Gauges will show Low Side going near 0 Psig or into a vacuum reading.
How do I know if my compressor or expansion valve is bad?
The type of system must be identified
The type of a/c compressor must be identified
Manifold Gauge Readings must be checked
PWM signals to the ECV must be inspected
Avoid unnecessary expensive repairs.
The air entering the cab is only slightly cool, and there are bubbles visible in the sight glass. there is usually about an 95% chance the restriction is expansion valve failed in the closed position related, 4% chance it is drier related and 1% chance it is somewhere else along the system or an internal drier desiccant bag rupture leading to a/c system contamination and restricting the metering orifice of the expansion valve.
Inaccurate refrigerant(freon) charges increase the chances of auto ac compressor lock up. Modern auto a/c systems require super accurate charging. Being off as little as 2 ounces can cause problems.R-134a and R-1234yf ac system tolerances require charge rates that must remain or should be charged within +/- 5% of OEM recommendation. SAE J2788 requires charge accuracy of +/- one-half ounce.
Attempting to charge by cans is History !!
Car ac compressor lock up due to improper compressor lubrication.
Refrigerant moves the oil inside the ac system and helps to cool down the ac compressor. An undercharge or overcharge refrigerant condition will increase the air conditioning compressor temperature and a change in oil viscosity and lubrication characteristics. Most compressor lock ups are the result of a lubrication problem.
AC compressors lock up due to ac system contamination
Auto ac compressor damage may occur because of system contamination. Anything more than the correct type of freon and oil is a contaminant. The use of sealers to fix small refrigerant leaks will cause oil and refrigerant contamination and ultimately ac compressor lock up. Sealer can’t be removed from the A/C systems. The contaminated components must be replaced.
The use of excessive Dye to help finding leaks in the ac system could create a contamination problem as well, increasing the normal working pressure of the ac compressor and the overall efficiency of the air conditioning system.
Improperly replacing any component in the automotive air conditioning system where the system must be opened for replacement of the damaged part and not evacuating the system before recharging it with the proper amount and type of refrigerant will contaminate the ac system with air. Air and moisture inside the system will create excessively high operating pressures and temperatures and eventually could lead to a compressor lock up.
Inefficient ac condensers and air conditioning compressor lock up
Debris on the condenser will affect the desuperheat, condensation and subcooling processes happening in the auto ac condenser.AC condenser with bent or missing fins will be unable to efficiently operate. An inefficient ac condenser will cause an auto ac compressor to lock up.
Low Refrigerant charge and electronically controlled compressor lock up ?
The car engines in vehicles with the clutchless compressors should not be run without refrigerant in the A/C system. Without refrigerant to move the oil, the auto ac compressor may not be properly lubricated and compressor lock up may result.
Do you need assistance inspecting the state of your ac compressor in your vehicle?
The receiver drier is a storage tank for the liquid refrigerant from the condenser. It also contains a bag of desiccant.
The purpose of the desiccant is to absorb any moisture that might enter the system during assembly or service. The receiver drier is often neglected when the air conditioning system is serviced or repaired. Failure to replace it can lead to poor system performance or replacement part failure.
When should I change my AC filter drier?
It is recommended that the receiver drier and /or its desiccant be changed whenever a component is replaced, the system has lost the refrigerant charge, or the system has been open to the atmosphere for any length of time.
AC receiver drier refrigerant flow restriction.
If the receiver-drier outlet is colder than the inlet, this unit is restricted and should be changed to restore efficient and proper system operation.
The air delivery system controls the movement of heated and cooled air into and throughout the passenger compartment. The Hvac housing is the plenum unit located and beneath the instrument panel. It contains the evaporator, heater core, the blower motor assembly, blower speed control device and the vacuum controlled door actuators.
The plenum houses the air doors and door actuators that direct airflow to the correct ductwork. The doors may be controlled by cables, vacuum, or electrical actuators. Single zone systems are usually equipped with three doors.
AC vacuum-controlled door actuator main fault
Automotive ac climate control panel levers may operate a rotary switch to select the various vacuum or air routings to the motors that control A/C modes. The main fault experienced with vacuum-controlled door actuators is vacuum leaks.
Do you need assistance with the ac vacuum-controlled door in your vehicle?
We have auto ac mechanics in your area in Miami-Dade County. Some ac door actuators may be located underneath the dashboard of the vehicle and to get access to them could be labor intensive. Give Us a Call Today!
How much does a car a/c condenser replacement cost will depend on the labor time and the price of the a/c condenser. The easiest to access auto a/c condensers will be on the lower end of the price range.
The price of the car a/c condenser replacement will depend on the condenser design and the manufacturer. Original Equipment Manufacturer a/c condenser will be on the higher end of the price range while Aftermarket condensers will be on the lower end of the price range.
Car A/C condenser price range.
Parts price difference will be mostly determined by the origin of the component. OEM are usually more expensive than aftermarket components. Different a/c condenser technology will impact the price. Newer designs tend to be more expensive than older designs.
A/C Condenser Cost : the price range is between $100 and $600 and will depend on the manufacturer ,make and model of the vehicle as well as the system type. Light and medium duty components are usually cheaper than heavy duty and off-road construction equipment a/c systems.
Car A/C condenser replacement labor estimates
Labor Price: Labor costs are estimated between $190 and $570
Vehicle Make and Model Condenser replacement
2017 Chevy Truck Suburban 5.3L
Remove and Replace labor time
*Does Not Include: Refrigerant Recovery or Evacuate & Recharge AC System.
2.2 Hours (according to Alldata Repair)
Can I Drive with an A/C condenser problem
Driving with a damaged condenser usually will not affect the vehicle’s engine operation. However, a severed restricted condenser coil may affect the flow of air used to cool down the engine and may cause an engine overheating condition. Leaking condenser will cause a low refrigerant low a/c oil condition and will allow the intrusion of air ,moisture and dirt into the a/c system. This condition will increase the complexity of the repair and the price.
Auto A/C Repair Near me in Miami.
Call Today if you need assistance repairing, replacing or doing maintenance to the a/c condenser in your vehicle. We have a mobile repair shop with ASE certified A/C mechanics near you in Hialeah, Miami Lakes, Hialeah Gardens, Doral and other areas in Miami-Dade County.
To know if a car a/c condenser is working properly the a/c condenser test can’t just be reduced to a leak test. The automotive air conditioner condenser must be tested for their heat exchange capacity. A comprehensive condenser coil test must include a detailed visual inspection to discover any defect or damages that could negatively affect the rate of heat rejection between the superheated refrigerant from inside the vehicle and the outside ambient air going through the condenser coil.
How to get colder air at the ac vents by improving the condenser heat rejection capacity.
A clean, well maintained car a/c condenser parallel-flow design will give the coldest air possible at the inside cabin vents if it is functioning according to manufacturer specifications. For the condenser to work at 100% efficiency it must be able to have all the built-in manufacturer improvements working as efficiently as possible.
A/C condenser corrosion will reduce the performance of the condenser. Corrosion, road debris or surface restriction on the condenser surface only means less working surface area for the heat exchange and condensation to happen. Any bent or missing fins will decrease the rate of heat exchange between the refrigerant and the outside ambient air ,creating an increase overload on the a/c compressor and increasing the overall head pressure of the air conditioning system. The automotive condenser is in most cases integrated on the front of the vehicle and uses outside ambient air as the medium into which heat is rejected .Any decrease in the volume of air flow through the coil will impact the condensation and subcooling process. Proper condenser fan assembly operation, condenser perimeter seal installation, and fan shroud is vital to the auto air conditioning system.
To improve the efficiency of the condenser and to make it smaller and less heavy ,the surface area of the auto a/c condenser has been extended with fins. Manufacturers have improved the designs of old inefficient condenser with new technologies that increase considerably the heat rejection rate of the automotive condenser. By improving the quality of the aluminum, the number of fins and internal refrigerant passages design the condensation happens closer to the outside ambient temperature. The new a/c condenser parallel-flow design plates and fins are bonded or soldered to increase heat transfer and to eliminate any contact resistance ( air gaps) that will reduce heat transfer. Headers at the inlet and outlet of the heat exchanger are also bonded to the plates through soldering.
The perfect automotive a/c condenser
A perfect condenser would condense the refrigerant at the same temperature as the ambient. The perfect condenser is not practical to be installed on the front of a vehicle inside the engine compartment, because it would be too large to reach this kind of efficiency. Our ASE certified mechanics can get you as close as possible to a perfect condenser operation by doing a condenser test ,maintenance or condenser replacement. Call Us today ! We have a mobile auto a/c shop operating in Hialeah, Miami Lakes, and Doral.
Air conditioning car systems are sealed at every connection using O-rings to avoid the refrigerant from venting into the atmosphere. O-rings are used at every connection of the air conditioning system creating a sealed system. The seals can withstand variable or constant pressures, high and low temperatures, preventing the venting of the refrigerant into the atmosphere.
The most common causes of a car O-ring failure and A/C leaks are the following
Incompatibility between the O-ring material and the fluid it is to seal.
The wrong O-ring size.
Improper O-ring installation.
Gland or cavity deformation.
O-ring dry installation or using the wrong type of lubrication
Car O-ring tools & installation to avoid air conditioning system leaks.
The use of the proper tools for O-ring installations are critical to avoid any damage to the O-ring surface. The use of sharp-edged tools, passing the O-rings over sharp threads, lack of lubrication and use of poor quality O-ring materials are the main causes of O-ring damage and possible air conditioning leaks. It is recommended the use of picks for removal & installation of the O-rings. Always lubricate the O-ring with the right type of oil and cover sharp threads before passing the O-ring over. Choosing the right size of O-rings for every application in the air conditioning system is crucial.
Where do most car AC leaks occur?
All sealed auto systems leak. Concentrate your efforts at car ac system connections and fittings as these are the most likely leak sites.
Every pressurized system leaks, because flaws exist at every joint fitting, seam, or weld. These flaws may be too small to detect with the best of leak detection equipment. But given time, vibration, temperature and environmental stress, these flaws become larger, detectable leaks.
It is technically incorrect to state that a unit has no leaks. All system has leaks to some degree. A sealed system which has operated for 10 years without ever needing a charge is called a tight system. The system still has leaks, but not enough leakage to read on a gauge or affect cooling performance. No pressurized system is perfect.
Refrigerant escapes at different times and at different rates. Leaks may plug, and then reopen under peculiar conditions. A leak is a physical path or hole , usually of irregular dimensions. The leak may be the tail end of a fracture, a speck of dirt on a gasket, or a microgroove between fittings
Types of auto ac refrigerant leaks
Types of leaks:
Passive leaks are leaks that can be detected while the unit is at rest of off. Standing leaks are the most common of all leaks.
Pressure dependent leaks are leaks can only be detected as the system pressure increase.
Temperature-dependent leaks are associated with the heat of expansion. They are usually due to high-temperature ambient air or condenser blockages or restrictions in the ac system.
Vibration dependent leaks only occur during a/c system operation. The mechanical strain of motion, rotation, refrigerant flow , or valve actuation are all associated with vibration-dependent leaks.
Combination dependent leaks are flaws that require two or more conditions in order to induce leakage.
How can I find where my AC is leaking?
Electronic Leak detector procedure according to EPA:
When using an electronic leak detector ,always follow the manufacturer’s operation instructions. In addition to the manufacturer’s instruction, the following should be observed
Always leak test with the engine off
Only a small amount of refrigerant is required to perform a leak test. A gauge reading of 50 psi is all that is needed. At temperatures below 50 F ,leaks may not be measurable , since 50 psi may not be attainable.
To avoid contaminating the tip of your leak detector, remove excessive dirt from suspected leak areas. Do not use cleaners or solvents, your detector may be sensitive to their ingredients.
Visually inspect the system , and look for signs of air conditioning oil leakage , damage , and corrosion on all lines, hoses and components . Each suspected area should be carefully checked.
Follow the system around in a continuous path to ensure that no areas are missed. If a leak is found , continue to check the remainder of the system for additional leaks.
At each area checked , move the probe tip around the location 1” per second while holding the probe no more than ¼ inch above the surface of the area being leak checked.
To verify an apparent leak, blow shop air into the area of the suspected leak to clear any refrigerant that may linger and repeat the leak check
An alternative method of leak testing is to use Nitrogen to pressurize the system, then pin-point leaks with a soap and water solution.
Do you need assistance leak testing your auto ac system ?