Saturday, May 6, 2000
G O O D  M O T O R I N G  A N D  Y O U

Catering for a cool car cabin
By H. Kishie Singh

THE air conditioner in the car is in great demand these days. For comfort inside the car, it should function to optimum efficiency.

The first move is to see if the gas is fully charged. This is easy enough and can be carried out by any competent AC mechanic. However you will do well to go to an authorised agent as he will have original spares should they be required. The side walk mechanic in Sectors 27 and 28 may be competent but the original spares that are a vital link and will promise efficient functioning may not be available.

One of the most common causes of the AC malfunction is the expansion valve. Subros and Sanden are the best known names in car air conditioning these days and original parts are available with authorised agents. Stay with the authorised agent and you will be a much happier person!

When you switch on the AC, there is an additional load on the engine. It is imperative that the engine cooling system is in perfect working condition, or else the car will overheat.

  Usually, the mechanics flush the radiator and refill it with coolant. This is a good move. Coolant that is a year old, loses its potency and needs to be replenished or replaced. The mechanic will also check out the water pump and fan belt. He may even blast compressed air or water through the condenser and the radiator.

And this could be the start of your problems.

The AC condenser and radiator both look alike and are placed next to each other with barely any space in between them. This is to prevent anything like a plastic bag getting stuck between the two and affecting the flow of air. It is most important that there should be a free and uninterrupted flow of air through the condenser and radiator.

In the normal course of driving, insects, dust and other grit will get into the condenser and radiator fins. These are thousands of small holes through which the air must flow to achieve the desired effect of cooling. In the case of the condenser, the cooling effect allows the gas to condense and become liquid. In the radiator, the hot coolant from the engine block is circulated and the air cools it. It is then re-circulated into the engine. Heat exchanger would be a more appropriate word for radiator.

It is the air rushing through the fins that makes the condenser and radiator function. We know that insects, dust get grit to in the fins. If you blast compressed air through the front of the car, the dirt from the condenser will be thrown into the radiator. So you will air-clean the condenser but choke the radiator. Now if you blast air from the rear of the radiator (heat exchanger), all the junk will be thrown back into the condenser. This way you will not solve a problem, simply transfer it!

The proper procedure would be to remove the radiator and wash it inside and out. It will also enable you to hose, under pressure, the engine block lines where the coolant circulates.

Now that the radiator has been removed, there is enough place to reach in behind the condenser and blow out the grit, towards the front, from where it entered. This whole operation, though simple, should be carried out by a competent mechanic in a workshop where you have compressed air and washing facilities.

This is the time to check hosepipes, clamps and fan belt. Refit the radiator, refill it with fresh coolant and you are assured of a cool car cabin.