Tuesday, July 15, 2014

Avoid the DIY A/C Charge

So summer time is here and you are feeling the heat. When you get into your car that has been parked outside in the hot sun in can be 150 degrees in there, and if you just roll down the window it doesn’t really help. If it’s 90 degrees outside, that’s better than 150 but it’s not enough to stay comfortable. Blowing 90 degree air into your face does nothing to cool you down like 36 degree air from your air conditioning system.

So you decide to see what you need to do to fix your A/C system. When you go to any auto parts store or any retail store with an automotive section you will always find a can of stuff to put into you’re A/C system to charge it. They say this will fix your A/C right up, and you can roll along in comfort. What they are selling is refrigerant in a can. This is required to make a refrigeration system, such as your A/C, function.

The problem is, charging the A/C is not as easy as adding a quart of oil to the engine, not only that but there are several things that can go wrong with your A/C, and running low on refrigerant is only one of them. To go even further, even if low refrigerant level is the cause of your lack of A/C performance, how do know this low level isn’t caused by a big leak that will cause your new can of refrigerant to run out in two or three days?

Sometimes the A/C quits working because it is low on refrigerant, and sometimes there is not really any reparable leak. If the system has slowly gotten warmer and warmer over the years then the possibility of just giving it a charge to repair becomes very likely. If the system was working normally one day, and then quit working over the course of a day or two, then charging the system will do no good because the refrigerant will just leak right back out.

The only way to determine what your system needs is to have a professional check it out. They will be able to determine exactly what is causing the A/C to blow warm air. They can check for leaks, and fix anything that might be a problem. They can determine exactly how low the system might be and they can charge the system with the exact amount of refrigerant that is needed to make things work perfectly.

When you buy a can of refrigerant from the store to do-it-yourself, you need to have knowledge of exactly how refrigeration works, and exactly how your system is set up, or you might overcharge it. Overcharging the system will not only make it function improperly and blow warm air, but it can lead to major damage within the system that could cost thousands of dollars to repair. Without the correct tools, over charging is very easy to do.

Some cans of refrigerant will come with a gauge that is to be used to determine how much charge is needed. This gauge is insufficient and will not work well enough, even in the hands of a professional. A professional will use a manifold gauge set that contains a gauge for high side readings, and a gauge for low side readings. Both sides must be viewed in order to determine if the system is properly charged. Even if you had the proper gauge set, there are no magic numbers that you can shoot for on the gauges to say the system is now full. Pressures change based on many factors and a good deal of experience is needed to determine if the pressures are correct for the vehicle and for ambient conditions.
A typical A/C gauge set.
Another problem with doing this yourself is many of the products that you can buy to charge your A/C system are not what you want and will cause further problems. For example, some cans of refrigerant come with compressor oil mixed into the refrigerant. This is never needed for a recharge but half the cans sold at auto parts stores have oil in them. Adding too much oil will cause the system to function improperly.

Some of the cans of refrigerant have stop leak added to them so that if you have a leak, the stop leak will supposedly fix it. As if to say just add a can and you will be all fixed up. This is especially bad. Any stop leak in any form is bad, but A/C stop leak is the worst stuff in the world. If you have this in your A/C system it will ruin many of the components in the system if an A/C line ever has to be opened for system repair.

Once A/C stop leak is exposed to air it solidifies and ruins all that it touches. Some shops will run tests on your vehicle before doing A/C work just to look for stop leak. If they get it in their A/C service equipment it can ruin the equipment. They run the test and if it comes back positive they may tell you to take a hike.

Run away from anything like this
Rarely do I ever advocate against a car owner dabbling in auto repair and maintenance, because I think it is so empowering for the individual car owner to learn how to take care of things themselves, but with A/C system service things are different. With so many variables in A/C repair don’t take a chance on the DIY A/C charge. Leave this job to the professionals. In the end it may cost you less money than messing it up on your own and then having the professional fix your mistakes. 

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