• Mr RPM L.B.

Air Conditioning for your Car or Truck

Car & Truck Air Conditioning or better known reference A/C here on the Sunshine Coast QLD is a vital part of our lives.

Times have changed and temperature changes are more dramatic. ( either that or we as humans have become a little soft and used to our now creature comforts. )

In this Blog as a licensed 134a gas handler and automotive repairer I'm going to give you an insiders look at your A/C system and the many parts that make up your system, Some times costly parts that can go wrong also.

Your Cars A/C is like a refrigerator, if it stops working it is usually 1 of 2 main points. Electrical fault or it has a leak and out of gas.

If a vehicle is low on Gas there is a pressure switch to cut the compressor clutch out and stop the system from working to protect the internal moving parts as they need lubrication from the 134A gas and oil.

So As pictured we have a series of parts:

* Compressor : This is the heart that pumps the gas around made up of mechanical and electrical components.

Possible reasons for failure: body seals can leak, nose con seal is the weakest point in an a/c system that can leak under high pressures, magnetic clutch fails creates heat and damages nose seal, internal equalising valves fail in some cases.

( people are often surprised why these are so expensive this is why, It's the heart. With installed costs that can vary from $900 - $1800 depending on your vehicles manufacturer.)

* High side pipe & hose assembly. ( red one that carries the hot compressed gas)

Possible reasons for failure: alloy pipe rubs on another component, if rubber, crimp fitting gives way or moves.

* Condensor: looks kind of like a radiator, that sits in front of your radiator. This is to cool the gas and change the properties of it. most are equipped with electric thermo fan attached to help the process.

Possible reasons for failure: exposed to rocks and road debris can put small holes in it, movement alloy is soft can rub through in some spots.

* Electric Thermo fan: ( in engine bay ) To cool the condensor as explained above. But if this unit fails it can cause damage to a number of internal components. as the high side pressures get too high the system expands and generally blows the compressor nose cone seal first but can also damage hoses & fittings, alloy welds in evaporators & condensors etc.

Possible reasons for failure: control relay has failed, motor has burned out with age, debris from road.

* Receiver Drier / Accumulator or Descant bag: The drier or now days A descant bag is to filter the system of moisture, but it does a lot more also it can filter small debris also.

These do not usually fail, but should be replaced with every annual A/C service which is recommended every 24 months or when the system is opened for repair of any kind.

* TX Valve ( thermostatic expansion valve ): controls normally the flow of liquid cold gas into the cars evaporator unit.

Possible reasons for failure: debris in the system, lack of lubrication & valve becomes jammed.

* Evaporator: The evaporator is one of the important parts that live deep inside your dash, normally housed with the heater core. This is what makes you cool. The cabin fan usually carries the air from the cold evaporator after it is mixed with the correct heat to create your desired dialed in room temperature.

Possible reasons for failure: debris & blockage internally, damage to core welds soft alloy, rub through due to movement and dirt built up in box over years due to condensation dust turns to mud and sticks to all internal components.

( The evaporator in most vehicles can be as expensive or if not more expensive than replacing a compressor. reason being most car and trucks require the entire dash removed to replace the evaporator. So pretty much everything between inner firewall and your seats, out then re installed. )

After outlining the main components and some of the reasons for failure, there are also a heap of electrical parts that are not pictured or mentioned.

* Compressor clutch relay: These can be a common problem in some vehicles.

* Pressure switch assembly: The pressure switch is made up of electrical and mechanical compounds that allows electricity to flow when a system is has adequate gas pressure. normal they can be 2-4 wire pressure switches some just control power trigger to the clutch relay and some control power trigger to both condensor fan relay and clutch relay.

* Evaporator blower motor fan assembly: This is in the dash. This fan recirculates and pushes the air from your vents.

* Cabin pollen filter assembly: Yes the pollen filter, like your cars engine air filter. the cab has its own pollen filter to stop you breathing in all of the dust that can be sucked up and recirculated in your vehicles cabin. these usually live inside of your dash accessible behind your glove box area.

When calling your local Air Conditioning Technician and saying how much for a regas you can now understand why they may tell you a few different estimated prices.

( 1 ) 1st should be if a system is looked at but can not be re-gased cause there is a problem. there is normally still a charge fee as there has been time and labour spent. Most good techs may have your vehicle also diagnosed for this charge also, but keep in mind with all of the technology there is these days some vehicles still may require further in-depth diagnostic time at further costs. And some slow leaking components like evaporators or hidden areas may take longer to find than others.

( 2 ) 2nd If a system is ok with first initial tests and can be regased normally a flat fee qouted regas fee applies. This normally would include labour, recovery, vacuum test sequence & regas with 134a gas UV dye injection & oil.

( 3 ) If there is a component or problem found which you choose to repair straight away. cost of parts & repair, maybe some diagnostic time and regas charges.

When it comes to gas as mentioned at the top there is only one that is approved by most manufacturers and you need a license to carry, that is 134A gas. ( apart from new euro vehicles that require a newer gas again.) Even though some may preach that there are cheaper gas options, my advice is it's not worth it.

Best advice I can offer is ask your repairer what gas they are going to put in your vehicle and if it's not 134a Gas its not good enough for your vehicle.

Well I hope this helps keep you and your families cool in our warmer months here on the Sunshine Coast QLD and if you have any questions feel free to give us a call in office hours or shoot us an email as per our contact page.

Cheers and thanks for reading:


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