Now that we have an idea of the role an AC compressor plays, let’s have a look at the AC condenser. If you have ever seeing an air conditioning condenser you might have mistaken it for your car’s radiator. This is common and not surprising at at all considering the job of an Air Conditioner condenser is same as the car radiator.
The AC Condenser’s sole job is to remove the heat from the super heated refrigerant, similar to how the radiator removes the heat from the engine coolant. The AC Condenser has intricate bends and folds which pull heat out of the refrigerant as it passes through. The peculiar turns the refrigerant takes through the nooks and crannies of the ac condenser combined with outside air removes heat from the refrigerant.
The removal of heat results in a change of state in the refrigerant. When the refrigerant initially entered the ac condenser, it was a super compressed and super heated gas. When the refrigerant leaves the AC condenser, it has been cooled down enough to change states from gas to liquid upon exiting.
Air Conditioning Condenser
The auto air conditioning system is, in layman’s terms, a refrigerator with a heavily modified set up for a car. The AC Compressor is an integral part of this layout. The AC compressor’s job is to compress and circulate the ac refrigerant throughout the system; think of it as literally, the heart of the system.
There are many AC compressors out there, in my experience the Sanden AC Compressor, Denso AC Compressor, Delphi AC Compressor and AC Delco AC compressor products are ahead of the pack. These encompass max RPM up to 9000, up to 7 pistons and (Denso especially) some of the quieter, vibration free AC compressors out there.
All these ac compressor performance numbers really mean is how efficiently and quietly a compressor pumps the refrigerant through the ac system. The AC compressor does this by first putting the refrigerant under pressure before sending it to the condenser.
Hybrid principals of chemistry and physics dictate the compression of a gas makes it extremely hot. The AC compressor’s other duty is to super heat the refrigerant. You need this because for an AC system to work, the gas needs to act as a high pressure gas source which will be used later.
What happens to this super heated gas once it leaves the AC compressor? I will cover that in Part 3 as it requires the introduction of another part – the condenser.
In general, a “neighborhood” mechanic understands how the car engine works and by extension, the role a radiator, a water pump, or an oxygen sensor. What I am noticing is a car’s ac system is not general car knowledge. So here is part one of a series on car air conditioning.
This time around, I will keep it simple and answer the following question – what is auto ac?
Auto air conditioning is a combination of the following 7 components. I will go over each one in greater detail in subsequent posts.
1. AC Compressor
2. AC Condenser
3. Orifice Tube
4. AC Evaporator
5. AC Receiver / Drier
6. AC Lines & Hoses
7. AC Blower Motor
So we’re finally in April, easter is coming and the weather is getting warmer. The one thing that always coming to mind is the need for Air Conditioning and the frequent failure of A/C Compressors.
There is not much maintenance you can do. These systems do unbeliveable amount of work and are constantly failing. You can service your A/C every 100,000 miles by having them flush, replace the ac drier and add new oil and freon. The new oil and clean system will help, but thats about it.
You will want make sure you replace the ac compressor and the a/c drier, these are both very important. The drier is the filter on the system and needs to be replaced. I have
I always get questions about Automotive A/C Compressor Electrical connections. What wire is ground? What wire is power? Plug changing? and so on and so on.
The first thing to know is that every manufacturer is different. Sanden ac compressor almost always has 2 wires coming out of the clutch coil. The question is always which is ground and which is power. The answer is that is doesn’t matter. Its just a loop, so you can power either one. This is true of almost all 12 volt systems. 24 volt for industrial applications will need to be looked at individually.
Many manufacturers like Visteon, Denso and Delphi use hard mounted plugs. See the picture below. This Ford AC Compressor made by Visteon has a fixed plug on it. You can see it just next to the belt. You will need to replace with the identical one. No getting around this. They do make some adapters, but you are pushing it at that point. They better have been tested to work on that application.
Most compressors come without the correct plug, this is an easy swap. Just cut the wires and swap the plug over.
What is an R4 air conditioning compressor and why is it used? Good question, but probably too much to answer here.
A rotary style compressor rotates internally at high speed to compressor the liquid refrigerant. The use of the spinning crank shaft enabled it to work fairly well and dramatically shrunk the size of compressors. It became popular in the 1980’s as a smaller, more energy efficient way to build an ac compressor.
Seen in the picture of the Chevrolet Suburban Compressor, rotary compressors were common in the mid to late 1980’s and up to the mid 1990’s. After that, the same idea of rotation was used, but in different ways. The were able to make them smaller, or use series of them to improve performance.
Today, the rotary compressor is still in use in many applications.
So one of the key steps in any AC compressor install is to turn the compressor to move the oil and refrigerant and begin the charge. The problem is that while this is common, not all compressors turn easily and many will not turn until the belt is on.
This started because someone told me they got a locked up compressor. It wouldn’t turn and wondered how that could have happened on a new air conditioning parts. Well the problem is that not all ac compressors turn by hand. Many do, but some don’t. These compressors will need the belt put on and used to turn the clutch.
This one was on a 97 Sierra GMC ac compressor. For these Delphi HD6 compressorsyou need to put the belt on, they simply are too tight. This is just the design of this style compressor. Be sure to check your book on which ones can be turned by hand and which ones cannot. The Delphi H series definately cannot. Some FS6 and others are hard to turn.
Many times when you are looking to replace a part, you have to figure out what you need first. This is true for many auto parts and in this case is true for a Chevrolet AC Compressor. In this case we needed to find a part number on the compressor to ensure we get the correct part.
Starting in about the 1970’s most auto parts began getting individual labels. This helped on the assembly line and also helps in the aftermarket. In this case when we are looking for a new ac compressor and the number will help us find an interchangeable part. It enables you to double check the part number and ensure you get the right part the first time.
These labels have lots of info on them and you can look at the picture for an example of a panasonic compressor. The key is to look for the part or model number, which in this example is noted as the compressor model. That should identify what the part is. The serial number is unique to that part and is fairly useless. The rest of the info is not that imporant, except maybe for the refrigerant type. In order to get the correct ac compressor you should be able to double check with supplier. They should be able to cross this.
I have spent alot of time talking about Black Death and showing black death pictures and i even copied them on my knol.
The black death pictures in previous blogs were of very bad systems. The picture below is from a Honda CRV Compressor. We did a quick test on the system by wiping the inside of the port. In this particular vehicle the contamination that was removed from the Sanden Compressor does not seem that much, but it is plenty to destroy a compressor. This particular compressor locked up and the system failed. Everything had to be replaced.
The lesson from this is that ANY contamination can destroy a system. In this case the level of black death may have been small, but it is way too much. It is crucial to thouroughly clean out the system to ensure you don’t destroy the new compressor. A small amount of debris will cause a compressor to fail.
I’ve spent lots of time talking about Black Death in an AC Compressor system. Even now on my knol.
Now I actually have a picture of the damage done by Black Death. You can look at the picture and see the before and after. Many people don’t believe this is possible, but here is the proof. It is pretty much proof positive that the Climate Control system is the most difficult system to work on because of its tendancy to destory other parts. Its could be classified a predator system.
I cannot stress to everyone working on this system that they must start clean. If there is any traces of contaminates in the system then the condenser and evaporator should also be changed. Do not take chances.
Let me know if you have any other cool pictures, I’ll post them up.
