I have dedicated a lot of pages to car AC problems. On this page I'm providing a condensed cheat sheet including some of the more important points made on the individual pages in the automotive air section.
Although this may be considered a review it still contains a lot of good information about AC not blowing cold. One of the things I have not hit on hard enough is repeat failures shortly after repairs. Auto AC systems are sensitive to moisture and dirt.
It's important when you open the system and start replacing parts that you're working in the cleanest conditions possible. Even the smallest particles of foreign matter in the AC system can contaminate the refrigerant and cause many different car air conditioning problems.
Some common problems would be corrosion from moisture and in the worst case scenario damage to the compressor can result from particles like metal flakes, sand or grit. When you are working on an air-conditioning system you really do need to have the right tools.
Maybe one of the most important of these tools would be a manifold gauge set. When the AC is not blowing cold, getting pressure readings from the low and the high side is important for efficient diagnosis. Another important tool is an evacuation pump.
you suck down the system it removes one of the biggest enemies that can
cause car AC problems which is moisture. Pulling 30 inches of vacuum on
the system and letting it sit that way for 30 minutes will remove even
the most stubborn amounts of moisture. These tools use to be expensive, but when purchased together in a kit they can be surprisingly affordable.
If you have an internal compressor failure you want to make sure you completely flush the system with the specialized liquid chemical to protect your investment in the new or re-manufactured compressor. Blowing air through the system is not good enough.
The AC oil in the lines can actually hold onto the tiny little metal
particles. This is why air-conditioning flushing is done with a special
fluid that removes the oil and the tiny little metal pieces. Properly flushing the lines is time consuming. Flat rate mechanics can be tempted to take short cuts and repeat repairs are the result.
If you skip this step or cut corners by not flushing all components, when you refill the system with Freon these little metal particles can work their way back to the new compressor and destroy it. I can't tell you how many times I have seen this.
Then it gets messy, as the customer blames the shop, the shop blames the parts company and the part company blames the shop. Meanwhile the driver is baking like a potato.
If you're working on an older car AC you need to identify what type of Freon is in the vehicle. This is because R-12 and R134a should never be mixed. If these two different types of Freon are mixed it will be considered contaminated and could cause an ongoing chain of car AC repairs.
This is why Freon service equipment has different fittings for the two different types of refrigerant. This prevents accidental mixing. Auto repair shops have separate recycling machines and service gauges to deal with the different types for this reason.
When an air conditioning isn't blowing cold enough and the complaint is coupled with a clicking compressor,
that's cycling on and off, you most likely have a system with a low freon charge.
A low system is the telltale sign of a small leak. Finding these leaks can be extremely difficult. This is why they came out with specialized tools to help in this kind of situation. The number one tool in my opinion to fight back against the AC leak is an electronic detector. You can also use florescent Tracer systems that also work extremely well.
This freon leak finding method uses a fluorescent dye that's added to the refrigerant charge and circulated through the system. Most of these kits come with specialized glasses and a black light.
Shining a black light will light up a fluorescent dye in even the smallest leaking areas. If your automotive air problems and questions have not been answered on this page head back to the repair modules section on the left navigation. This area has about 10 more pages on the subject of auto AC diagnosis.
Give this air not blowing cold page a bookmark or share with a friend having auto AC problems.
If a vehicle is suffering from small leak syndrome you might be recharging it on a regular basis. This next page provides more information about this condition that happens to be a common car AC problem.
The homepage is up next and provides a good run down of what else is offered on the You Fix Cars website. You can also find out how to get answers to your auto repair questions.