How to Fix Car Air Conditioning

Dave: Todays lesson automotive air conditioning. Let's choose this Subaru was a prime example of how stuff works. And it's so hot today, it's 31 degree Celsius I could use some air conditioning well it all starts with the compressor that thing right there. Every car compressor has a clutch you know that thing, the outside of the clutch if the belt runs on free wheels all the time even though when the air conditioning is not on. The part that drives shaft inside the compressor this is dry plate, power set to this wire electromagnets turned on in this dry plate is sucked into the fly wheel on this crankshaft turning pulley and drives all the mechanism inside the compressor. It works just slightly fridge compressor or air conditioning compressor in your window unit. Now somewhere on the low side tubing that is on your air conditioning system is using a switch. Sometimes the switch is even on the compressor what that switch does is when the air conditioning gas gets too low which is called freon, that switch shuts off and clutch cannot operate. Sometimes when there is a leak in the system the oil that's inside that compressor which is a little bit flowing through all the pipes at the same time is the air conditioning system is working is leaking out along with the freon. Then at the system continued to function with no gas it may have leaked out all the oil at the same time and then you seize up your compressor and they are expensive on many cars they are in a God-forsaken spot way down there, or you dread trying to take them out. Well every car works pretty much the same, same as a window air conditioner essential air. It have the high side pipe, which goes out to the condenser coil which is another radiator in front of your, you know your engine cooling radiator using some more on the other side there is a tube coming out and it goes to the dashboard, where there is another radiator called the evaporator, also coming from the dashboard not at the firewall is that large pipe I just showed you which is the low pressure pipe, where the compressor sucks the gas back in again to be recompressed and come out of the high pressure pipe. And this car the high pressure pipe runs along this vendor. It goes to a aluminum bottle, it's probably about 8 inches long and that's called the receiver, drier, or collective bottle. It has a filter in it and some powdered chemicals it absorb any possibility of moisture in the air you know like water or something and also filters it freon because as compressors wear out little grey bits and particles of metal end up in the system. Older cars, over the 1992 use to run off or twelve Freon gas. Well that burns my as on hot days and that stuff gets up in this sky and ruins the ozone and we get more rays, so the hot compressed gas comes out goes into the condensing coil, which we can see but just looks like aluminium radiator exit here as it is cool to air temperature and on truck we will drive vehicles we have one or two electric fans that turn on to move air across there when the car is not moving so your air conditioning system doesn't over heat. When your air conditioning system does over heat using installs the clutch, it starts making screeching noises or the belt slips. On General Motors cars, this tube it's exiting the front condensing coil has a little filter sock made of stainless steel some are inside, looks like oven mash. That thing sometimes gets clogged and you wonder why your systems were charge you are not getting air conditioning. Also on General motors cars and several other cars inside that tube that's exiting the condenser going to the firewall, is a one way valve, what kind like a one way valve it shape like this and as the gas passes through that space as I am showing between my fingers the pressure pushes the valve open the valve is sort of spring loaded. So on these cars even, when they are low on freon or have the right amount of freon if you test the pressure and the net -- if you charging a system or checking it it's always showing the right pressure unless it's just about has no gas at all because this valve opens and adjust itself by the rate of flow depending on how fast your compress it turning or engine RPM you have. Many cars don't have that system; they just have a TX valve or something like that as I explained in the earlier video. Well, the most common problem with car air conditioning is Freon leaks. One place where they don't leak that often but do sometimes is the sealing behind the clutch, you will see a big wet spot underneath the bottom of your compressor and sometimes block all the way around here, another place where they leak on the compressor is the compressor body some bodies are made in two-half's, bolted together some are three pieces bolted together and in between the aluminum housings is big O rings. Well on compressors that are near the bottom like many cars. They get a lot of roads black spray from water and salt debri and stuff like that and corrosion gets between these tiny spaces between the compressor hosings each side on the O rings and even the compressor housing leaks. They often have wherever there is a joint a quick kind of connection and O rings in there and as the O rings get old and tired you gets leaks around all the joints at the same time that sucks on very many Chrysler products from 1992 and throughout the rest of the 90s. Inside your firewall under your dashboard, where the evaporator is you have the most serious leak of all, the hardest to fix one that's your evaporator goes bad. This is the chronic problem with those cars and especially some GM cars too. Its can take seven to nine hours to repair the whole dashboards during column and wiring hard as just to change one part, when you get a leak on the front condensing radiator it was a slow one sometimes you can see it. You will see like oily black dusty grease spots, if you see any of those change your condensing radiator unless it's just cut under coding spray on it or something. When you're want to recharge your car air conditioning, you are supposed to fix the leak first because its just like a tire, once this got a hole, it doesn't get better, it gets worse. So if you don't fix the holes all they leak out against, it will wastage expensive gas and possibly damaged or ozone that when you do get the point of repaired leaks, you find the nipple on the largest tube, the low pressure tube. You screw your charging belt getting from their low pressure gauge to it. Now if you know, what kind of gas is in there and it's not completely empty so there is some pressure you can just add more. Always hook the pressure bottle or Freon bottle up to the middle port on your charging manifold. Make sure your manifold is not set by any moving parts; you don't want to get eaten when you start your car. Now the proper way to do this on a front wheel drive car on a warm day is to run a garden hose on a condensing radiator into the drill, that keeps cold water running on it because that will drive cars just at that great you are getting a lot of air over the condensing radiator well the car is idling so you won't get the correct charge that changes the pressure. If your air conditioning systems starts overheat while being charged then the pressure in a low side goes up to and you will incorrectly charge it. So if you don't have one of those variables weighing belts in your output system, I mean your exit tube then of course you would charge it up to about 30 to 40 PSI while running at about 1500 to 2000 RPM with the garden hose on there. Be rub your engine up is not uncommon for it to drop down any where form 17 to say 23 PSI that's normal. If you let it idle at you know seven 800 RPM it's not uncommon for it to jump up the 45 PSI that's on normal except for the cars with the valve in there. They all will seem to run at the same pressure. Now if you don't have your handy dandy set of manifold gauges you can always red neck charge something just with the hose, that's it nothing else and you can get a perfect charge that way, so only just you have a garden hose on there what to do is just screw the hose on, start adding Freon while you are running at about 12 to 1500 RPM hose running and you hold your hand on the exit tube coming from the firewall the large diameter one. As soon as it gets ready cold start right away, it means you have got enough Freon that means it's enough Freon to hold the complete radiator that's inside the dashboard and have a little bit left over to come out the exit tube and that go to compressor then you know you are done so if you bought one of those handy, dandy little bottles from the automotive store that have who knows what kind of gas in it you don't have charging gauges well that's how you know you haven't overcharged it or undercharge. So do it that way, it will always work. Now there is a couple of different ways to test for leaks on any kind of air conditioning system. This was called electronic leak detector, sticking right now looks like a -- starts to tick faster when you getting there a leak. I will turn the sensitivity adjustment to show you -- you get an idea of the sound it will make, if you happen to touch the part of the pipe it's leaking, but watch out if the pipe has water vapor on it or any kind of liquid. The liquid can often set this beeper up to and give you a false reading or if you push it right against flat surface and block all of the air, it will give you a false reading too. Unfortunately sometimes you got to take this little probe around every square inch of surface of pipes, radiators, compressor, just to find the stupid leak and that's still won't find a leak of it's under the dash. The other more common method today is fluorescent dye; it's often green or pink colored. They pumped into the low pressure system pressurize the system, run the system for a while shut it down give it a bit of time to leak and then they shine in ultraviolet light on every surface area of every tube and part on the system and look there what goes that's actually the best system it's pretty effective. I like it, Hebrew we had the repair is an easy repair system, all the tubes are high up, lots of space but that's not true from most cars. Most cars they charge you an -- because the tubes are so difficult to replace on their leak and salt eats aluminum and, of course, in Canada we get lots of salt on the road so the system gets heat now during the winter time and very common when you take one pipe apart that they are fitting is well but together to the other pipe and both pipes are to be repaired because the fitting breaks. If you notice when your car is idling and the air conditioning is on and it's constantly rapidly clicking the compressor clutch on then off, on then off, that's telling you, you got low Freon. Of course if it doesn't click on it all telling you here is an electrical malfunction a back clutch or no Freon at all. It is normal once the system gets that inside of the car fully cold and the system is working really well for the compressor to cycle off for little bits of time just because it's doesn't want to run it overcapacity. Nowadays there are so many different gases you can put in your car to make it all better or sort of better depending on how you fixed it. There is the old R-12, which you can smuggle into Mexico and go to jail for. The one kind of gas you can never reuse in a car is R22 from a window air conditioner; its pressure is so high that it will just stall your compressor out in a system malfunction. Even popping the work believe it or not, but if you get an accident you might get a big fire ball there is R4, R3, R1, 34A that's the best one and there is a whole bunch of other ones with funky names and product names and patterns, so you can buy nowadays at your automotive store cheap for red necks who don't want to get a professional job done. Now the last important piece of information is if you did replace a part of your air conditioning system or there is was no gas in it when you went to recharge it it's got air in the pipes automatically it has air in the pipes and your system will function horribly if you don't get the air out of the pipes, it might even ruin your compressor and air contains moisture and that's very bad for a system. There are things called vacuum pumps I just don't have one in front of me right now. But what it does you can hook it on to this line if you gauge set, open all the gauges shut off the bottle and vacuum all the air out of your system once all the leaks are fixed. Then when the -- for ten minutes to an hour who knows along the system been opened along you want a vacuum some more chance there is moisture in there, once it is being vacuumed sucks your machine off and it's on the ground, shut all your valves off, turn your bottle back on, then start the car up and do the charging process. If you want to add more oil to your compressor vacuum at this system I just explained, then unhook this tube, pinch it off with a wise grip, stick this end into your container of oil and pinch the wise grip and the vacuum in your system will suck the oil into the system and lubricate the compressor in case your compressor leaked or all the oil leaked out one of the pipes. Compressors don't take a whole lot of oil anywhere from like three to six ounces so don't over charge them or you will stall them out and bust the pistons are been inside and you are ruining your compressor. So now you know how it works, you know how to fix it. All of you know where to get some gas from, you have a few tools, you know now to fix your car and make it work perfect.