Much needs to be cleared up regarding use of long-lasting antifreeze in cooling systems of water-cooled cars with air conditioning. Consider the case of John H. With a 60 per cent solution of ethylene glycol in the system the boiling point was raised to 231 degrees. He rightly figured that the engine would run hotter with the conditioner operating, and he knew this antifreeze would thus help prevent coolant loss out the overflow, but he failed to figure that this was covering up urgent need for service. The engine did not immediately lose coolant, but it ran much too hot. This thinned down the oil, brought on clicking of the hydraulic valve lifters, and pinging. Then, on a long hill, things began to happen. Suddenly the engine’s temperature hit the danger point, the automatic transmission began slipping and the radiator pressure cap’s valve opened up. A real mess.
Use of long-lasting antifreeze is important to air conditioning success, but be sure the cooling system is in top form. Make certain that ignition timing is on the nose, that there is no slippage in the automatic transmission and that the engine operates on high enough octane gas.
Few motorists realize that the effectiveness of any cooling system depends upon the number and size of the passengers carried. Body heat is extra work for the heat transfer system. Often it is on a hot day when you feel like loading the car with friends and relatives for a trip, and that’s when insufficient cooling is likely to be the result, especially since the engine also is working harder. If the car has been standing in the sun, you should always drive a mile or two with the windows open to get the inside temperature down to normal before switching on the air conditioner.
During traffic stops it is better not to use the conditioner. Prolonged idling at will temperatures above 90 degrees cause excessively high compressor pressure. Switch off the system when climbing long grades. It is a good idea to test the system’s efficiency with the aid of a thermometer held at an air outlet, with the conditioner switched on and the engine running around 1500 rpm. Without the thermometer test we often are mistaken as to just how effective the conditioner is.
In winter always operate the system twice a month so as to keep oil around the seal in the compressor. Unless this is done there will be leakage of refrigerant from the system and insufficient cooling, later. Incidentally, when the system does not seem to be doing a good job, check the ducts of the car’s heater and defroster. Air may be entering here.
A blown fuse for the blower will, of course, make the system ineffective. Failure will also result if the clutch doesn’t get into the act when the conditioner is turned on, or doesn’t cut in when the automatic control calls for more compressor action after a rest period. The magnetic clutch draws only 1.8 amperes, but the blower on High draws as much as 7.5 amperes.
You can observe the refrigerant flowing into the system by looking at the sight glass atop the receiver while the cooling control is set at maximum and the engine is running at 1500 rpm. If foam appears, the refrigerant supply is low. Add more refrigerant until bubbles disappear. Depending on the system’s capacity, a little more refrigerant should then be added forgood measure. Because refrigerant must be handled carefully (it is highly dangerous if it gets into the eyes), owners are urged to leave the actual job of adding refrigerant to a mechanic who specializes in this work. Safety goggles should be worn when working on any part of the system. Keep this in mind if you are doing motor work and might accidentally open up one of the air conditioner lines. Have your goggles nearby.
It will help the system do a better job on a summer day if you remember to keep the engine’s radiator and the evaporator free of accumulations of leaves and dead insects. Make sure, too, that the fan belt is tight enough and that the engine has sufficient oil of the type it requires. Just because you can get more breeze with a convertible going at top speed is no reason to overlook the fact that you’ll get more efficient artificial cooling in a closed car if you don’t push its engine too hard. To keep cool, take it easy.