You may not have thought about this, but your car has two cooling systems: one that cools the engine and another – the air-conditioning system (A/C) — that cools the passenger compartment.
In my previous blog, I described the system that keeps your car’s engine cool, and provided tips for maintaining and extending the life of that cooling system. CLICK HERE to read that entry. Now let’s look at the system that keeps you cool.
How Air Conditioning Works
Your A/C system uses a refrigerant gas, which is first compressed into a liquid, then allowed to condense and finally to evaporate back into a gas. As it evaporates, it absorbs heat from the passenger compartment and a fan blows the cooled air back into the car through the air vents. Imagine steam cooling down and condensing into water, and you have the idea.
When You Have an Air Conditioning Problem
When the air conditioner isn’t blowing enough cool air into the passenger compartment, you need to have the air conditioning system checked. The most likely cause of not getting cold enough is that your system has lost some of its refrigerant and may need to have the system “recharged” with more Freon. There are glass ports on some of the older cars that will show bubbles if the system is low on Freon gas. Most cars require pressure gauges to be attached to read the pressure. Because of strict regulations in California, you need to take your car to a person who has a specialized license to do this they of work. So, you can’t check or fix the A/C on your own; because that gas under pressure is a sealed system. You must have it checked at a shop that has a license and equipment to do this work.
How We Service Air Conditioning Systems
Air conditioning service is a three-step process, and it generally takes an hour to perform.
- First, we use equipment to remove the refrigerant from the system.
- Next, we lower the pressure in the system below the pressure of the air outside and hold it that way for about 20 minutes to detect any leaks. If we detect a leak, we have to repair it before we can recharge the system. If we don’t detect any leaks, we can add the correct amount of refrigerant gas back into the system.
To check for leaks, most technicians prefer the ultraviolet system: a technician injects dye into the A/C system, then shines an ultraviolet light along the hoses that the gas flows through both under the hood and under the dashboard. The ultraviolet light illuminates any escaping dye, and the technician wears bright yellow plastic glasses to see the illuminated dye. This system is virtually foolproof!
Refrigerant Gas: 134a vs. Freon/R12
All cars 1993 or newer use an environmentally safe refrigerant called 134a. The refrigerant gas is highly specialized. Older cars use Freon, also called R12, which, due to environmental restrictions, is no longer manufactured, anywhere. There is a dwindling supply of this type of Freon because it was regulated out of existence once it was determined that it depletes the atmosphere’s ozone layer, and it’s very expensive. However, most shops are able to convert an old R12 system to an R134a system. This conversion isn’t cheap, but we recommend that you do it because of the cost of the R12. Ultimately, supplies of R12 will be entirely depleted, and all pre-1993 A/C systems will have to be converted. Most shops that do A/C work stock conversion kits, and have plenty of experience in doing the conversions.
I hope these hints will help you stay cool.
Wishing you safe, happy motoring.
Owner, Hillside Auto Repair