Tag: auto ac mechanic near me

ac o rings and seals

Air conditioning car system O-ring leaks

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

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:

  • Standing leaks
  • Pressure-dependent leaks
  • Temperature-dependent leaks
  • Vibration-dependent leaks
  • Combination-dependent leaks.
Standing 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:

Pressure dependent leaks are leaks can only be detected as the system pressure increase.

Temperature-dependent leaks:

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:

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:

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

  1. Always leak test with the engine off
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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

Alternate methods:

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 ?

Call Today ! We have car ac mechanics near you.

auto ac compressor lock up

What causes an ac compressor to lock up

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?

Call Us today ! We have automotive ac specialists near you.

How to replace an auto ac receiver drier.
Receiver-drier location.

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.

ac vacuum controlled door

AC vacuum controlled door.


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.


hvac box showing harness ,door actuators and vents.

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!

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