Blog


 
car air-conditioner compressor and condenser

This is about your car air-conditioning system and why it doesn't cool as cold as you would like it to.


The diagram to the left is a map of the air-conditioner components and their respective relationships to each other. If one fails they all fail.

All Car Air Conditioning (A/C) Systems require regular servicing to keep them working effectively and to prolong the life span of their components. We use only R134a. Unfortunately, refrigerants readily absorb water which turns them corrosive. It’s quite normal for a small percentage of the refrigerant charge to be lost from your car’s system via the pores in the rubber hose sections from year to year, so even when everything is in perfect order, your system will need to be recharged at some stage.

The purpose of YEARLY servicing of your car’s air-conditioning system is twofold: Firstly, doing this will ensure that your system is operating on a full charge of clean refrigerant and therefore, working at its best for your comfort and long term economy. Secondly, it will ensure that your system is free from contaminants such as air and moisture, which can cause out-of-range pressures and poor performance or even worse; internal corrosion within your A/C system, possibly leading to leaks and premature component failure (Resulting in avoidable, expensive repairs). The maximum permissible level of moisture in a car A/C system is less than 4 parts per million; virtually nothing!

The filter/receiver/drier is an integral part of your cars A/C system that has been designed primarily to trap moisture thus effectively removing it from the system, and preventing it’s corrosive damage. This DRYING action is chemical in nature, so it can’t go on endlessly, this is why it is very important to replace the filter/receiver/drier at specific intervals (we recommend every 2 years for most cars, or any time the system has been opened to the atmosphere).
 
car air-conditioner compressor

What is the Retrofitting all about and why it is necessary?


Refrigerant R12 was used in a car air-conditioning systems from their very beginning, right up until the 90’s. It has been proven that R12 damages the environment by depleting the earth’s Ozone layer (part of the atmosphere that filters out harmful rays from the sun).

Foremost governments around the world (including Australia) have signed protocols promising the reduction and eventual complete phasing out of ozone depleting substances. The alternative for old R12 systems is to modify them in order to make them suitable for the use of R134a refrigerant, which is the standard refrigerant used in all new cars. This modifying process to make an old R12 system for R134a is commonly referred to as Retrofitting. It basically involves modifying the service ports of the R12 system so they will accept R134a service hoses, replacing the filter/receiver/drier, changing the original mineral oil to a synthetic oil compatible with R134a and replacing some of the “O-ring” seals.
 
car air-conditioner compressor and condenser

What causes that unpleasant smell from my car's air-conditioning system?


During normal operation, the air-conditioning system draws hot, humid air into the evaporator (cooling chamber), where the falling temperature forces the moisture in the air to condense onto the cold evaporator fins. Dirt, dust, hair and lint from the passing air sticks onto the wet surfaces. The continual condensing of water droplets is meant to self-cleanse the evaporator but sometimes dust and dirt can build up and trap mould spores, causing a foul odour.
Special sanitising products are available for the purpose of ridding odour causing mould and mildew from your car’s evaporator unit. We recommend that you allow us to carry out this service for you. However, our personal recommendation is to have the evaporator taken out and thoroughly cleaned, the advantage here is that the air passages are returned to as new capabilities.
 
car air-conditioner compressor and condenser

What is the white vapour that I sometimes see streaming from my car's air-conditioner vents? Is it escaping gas? Is it harmful?


If you have seen an odourless white vapour emitting from your A/C vents but afterwards, your A/C is still operating OK, it is extremely unlikely that it was escaping refrigerant that you could see. Vaporised refrigerant (gas) is not normally visible, therefore, for you to see escaping refrigerant, it would have to be liquefied refrigerant escaping (which requires a very big leak). In such a case, your system would become completely empty within an hour or two, if not in minutes.

This odourless white vapour is most likely caused by humidity, in which case what you would be seeing is actually very small water droplets which condense out of the hot, humid air as it is cooled, then quickly disappears as they vaporise again when they mix with warm air inside your car. It happens when hot humid air passes through the air-conditioner cooling chamber too fast for all the condensing moisture in the air to form into water droplets on the cold metal fins of the evaporator core and are carried by the air through the outlet vents in your dash. This water vapour is not harmful and usually doesn’t persist for long periods but by selecting recycled air from inside your car rather than outside air will often stop water vapour forming (the recycled air inside the car will generally be lower in humidity than the outside air).
 
car air-conditioner compressor and condenser

Operational Tips:


Your car's air-conditioning system is far more efficient than the heater at defogging the windows of your car in damp weather conditions – turn it on along with your heater for clearer views! (Once your car’s engine is at normal operating temperature running the heater and the air-conditioner together will produce warm, dry air).
You should try to run your cars A/C system for at least 5 minutes a week regardless of summer or winter weather.
 
car air-conditioner compressor and condenser

The main cause of poor airflow from the vents.


If your car’s air-conditioning is not performing at it’s best, having the system checked sooner rather than later will mean less discomfort and less expense. There are several common reasons for weak airflow in car air-conditioning systems, some of which can be fixed at home and others that require the expertise of professional technicians.

The growth of Mould and mildew in your evaporator.


The presence of moisture inside auto air conditioner units can be the ideal environment for mould and mildew to thrive. This can reduce airflow by blocking the fins at your evaporator behind the dashboard as well as producing unpleasant odours in the cabin and putting the health of you and your passengers at risk.

Cleaning your evaporator using a good quality metal cleaner will normally eradicate mould and mildew. You should also use an anti-bacterial cleaner to remove any harmful germs from the system. Running the defrost mode regularly will help to keep your air conditioner dry and prevent further issues.
 

Loose hoses or seals


Another common cause of weak airflow is that the blower hose has come loose, meaning that air is not passing through the evaporator into the cabin. There could also be a problem with one of the multiple seals in the system, which need to remain tightly closed to ensure air is able to pass through. Hoses and seals should only ever be repaired or replaced by a professional technician.
 

Blocked cabin air filters


The cabin air filter, also called a pollen filter, is typically located before your blower motor and acts a filtration system between the outside air and the cabin of your car. Any pollens, dirt and leaves or just general road debris gets stopped at the cabin filter to ensure you and your your passengers are only breathing clean air. Cabin filters do not last forever and should be changed every 20,000 km or sooner in severe conditions.
 

A Faulty fan


The ventilation fan is responsible for blowing air over the evaporator unit, which is cooled by the refrigerant before entering the cabin. If airflow is weak or non-existent, the fan may be damaged and will need to be replaced for normal operation to resume.
 

Car repairs in Rockhampton


Highway Auto offers same day auto air-conditioning repairs in Rockhampton. Talk to our air-conditioning manager today (07)4926 1303.