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Keeping it cool: Car AC servicing simplified

18th Apr 2017 11:00 am

Here are the crucial bits you should know about your car’s air-conditioning system before you get it serviced.

We're already a fair way into summer with the dreadful month of May just around the corner. Of course, air-conditioning comes into sharp focus during these scorching times and none more so than the units in our cars, given that temperatures inside the cabin can shoot up to as high as 60 degree Centigrade on some of the hotter days. To help the car’s air-con unit deal with high cabin temperatures, it is vital to get your car's AC unit serviced.

What you should be aware of is that ‘AC servicing’ is a broad and general term, and the system itself is quite complex with a lot of parts working together. These parts are the evaporator, blower, expansion valve, compressor, drier and condenser. With so many parts, most car owners aren’t able to decipher what the actual trouble is when they sense that there is insufficient cooling. To make things easier, we have compiled a list of Frequently Asked Questions. This will give you the sufficient know-how to question the mechanic and find out if he has done a thorough job.

What are the common issues that plague the AC unit?

There are a number of things that can go wrong with an automotive air-conditioning system. Dirt and moisture are the main culprits. Unfortunately, both of these are abundant in our country. A common issue is blockages in filters and condenser caused by build-up of dust and dirt which prevents the flow of air over the cooling coils. Another area where dust accumulates is the blower or fan unit of the AC. Bits and pieces of papers and waste are also known to make their way into the blower.


Dust and dirt build-up can block flow of air.
 

Another common issue is the leakage of refrigerant. The R134A-grade refrigerant currently in use in cars sold in India has a low boiling point and can leak from different places in the air-conditioning system. These are joints in the piping, pressure release valve and front seal of the compressor. The refrigerant can be topped up using specialised equipment called Recovery Recycling and Gas recharging machine. The R134A doesn’t cause damage to the ozone layer but does need to be handled with care when being replenished.

Then there is the compressor. Among the more expensive parts of the system; things that go wrong with it are the wearing of magnetic clutch and pistons, and leaks in the oil rings. All these are generally down to excess load put on it during use. Usually, this happens when the car owner has ignored manufacturer-recommended AC maintenance schedules. This ends up causing the entire system to work under excess load conditions and it’s the compressor that gives way more often than not. Another common problem noted is of rodents finding their way into the blower unit.

What happens during a routine AC service?

Since the air-conditioning system has to deal with dust and dirt in the environment, some parts like the condenser coil placed at the front of the vehicle and the blower fan placed behind the dashboard, need cleaning. To access these parts, some other parts have to be undone. Depending on the car model, the bumper is removed to access the condenser unit, usually placed below the radiator. The condenser is responsible for releasing the heat from the cabin to the atmosphere. This is cleaned with a high- pressure water jet to rid the dirt and dust.

The next step is to further clean them using special cleaning reagents and a brush which gets rid of the tougher blockages. The bumper is then placed back in its original position and electrical connections for horn and lights reconnected. A filter is also placed inside the cabin which has to be serviced. There are two types depending on the car model; paper type, which has to be replaced and a wire mesh type, which is washed and dried and placed back again. For some cars, the filter is placed inside the blower unit which will entail a lot more work. This also allows the blower to be cleaned and rid of blockages that reduce the amount of air passing through the vents.
 

Cooling should be good at all blower speeds

Unless you reside in the northern or hilly regions, it’s likely that your car’s air conditioner is used throughout the year. So, naturally, regular maintenance is a must. We suggest getting the AC serviced at least once a year. Most authorised service outlets have an automated recovery and recycling machine which automatically detects and replenishes the refrigerant in the AC system. There are specialised outlets with similar facilities and cost comparatively less than manufacturer-authorised service centres. But to get the best performance, remember to clean the interiors so that the filters don’t get dirty and let the hot air out of the cabin before setting off.
 

Checklist

  • Ensure the AC technician completes the following tasks
  • Replaces the air filter
  • Cleans the blower unit of the AC or fan and the condenser coil
  • Replaces the compressor oil
  • Flushes the AC system and tops up the refrigerant
  • Checks if the the electrical connections are fine

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