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Black Death as it is called by the air-conditioning service professional, is what happens to some air-conditioning systems. This syndrome is more prevalent in the Ford FX and FS series compressors as well as some others.
These compressors were designed with Teflon coated rings. In time, these rings begin to "shed" which throws Teflon from the compressor into the condenser. This "shedding" begins to collect and trap the system lubricant, which worsens the shedding, and eventually enough of the Teflon is gone to allow the aluminum to rub the cylinder wall. This causes enormous heat to be built up inside the compressor, eventually hot enough to melt the aluminum and seize the compressor.
What you are left with, besides a seized compressor, is a black, gritty, gooey mess inside of the system. This goo, we call "black death", is normally trapped between the high pressure port of the compressor and the high pressure side of the orifice tube, however, it is slightly possible for some of the smaller particles to get through the filter screen, and cause deposits in the low pressure side of the system.
The problem with this goo is getting it out. You must clean this stuff out of the system before replacing any system components, failure to do so will guarantee another failure, but with proper service and flushing, you can expect a long lasting system. The best and most recommended repair after a failure such as this is know as a "firewall forward" replacement. What this means is that all system components from the firewall to the front bumper are replaced, this means all components, except those normally found in the passenger compartment of the vehicle. Doing this type of repair is the most expensive route, but, will insure a long lasting system, as long as the service is done properly, and the system is properly maintained afterwards.
There are other options though, but, you lower your chances of not experiencing this problem again. There are parts that must be replaced, no real way around these, they are:
1. The compressor. If you have a black death compressor, the best option is to use a new compressor, or at the least a quality rebuilt, and you wont find a quality rebuild at a chain discount auto parts store, you have to order them from a direct ac supplier, or a top name brand parts store.
2. The orifice tube. This is normally affixed in the liquid line, and the entire line assembly should be replaced.
3. The liquid line. If your o-tube is not a part of the liquid line, replace this line. The liquid line is the line that runs from the exit side of the condenser to the entrance to the o-tube, expansion valve, or evaporator..
4. The filter dryer or accumulator dryer. This is a black or silver canister usually found on or near the firewall, or up towards the condenser. This canister filters moisture from the system, and collects liquid refrigerant to prevent damage to the compressor. It will also collect black death goo, and must be replaced.
Those are the must replace items. The condenser can sometimes be flushed and the goo removed, but, it is best to replace it. Since the inception of r-134a and other alternatives, the condenser has under gone many technical advances. New designs and materials have made the condenser much more efficient, and given it the ability to dissipate much more heat than the old style r-12 condenser did, this allows for much better system performance and better fuel economy. With the cost of flushing solvents, time, hassle, and the added benefits of replacement, it is in the best interest of the vehicle owner to replace the condenser.
If replacement is not an option for the vehicle owner, then flushing is the only option. There are many different ways and many different opinions on how to flush. I have found what works best for me is to use lacquer thinner, allowing it to soak and saturate the goo, then forcing it out with clean compressed air, and repeating until the expelled lacquer thinner is clean and clear, and following this with 141b ac system flush or similar. This method works best for me, but other techs have their ways of flushing also, either way, the end result is still the same, the goo must be removed, completely and thoroughly, and you have to repeat the flushing until all the goo and any other non refrigerant compatible material is removed from the condenser. You can use a coffee filter and jar to collect samples to see if there are any more particulate being flushed out. You can use this same method on all of the components with exception of the compressor, accumulator dryer, and the filter dryer. It is not preferable to flush the evaporator, but, in some cases you have to. In these worst cases, make sure to use a flushing agent that has a high evaporation rate, such as 141b or similar.
If you have any questions about black death or how to repair your air-conditioning system, feel free to ask the techs at:
The Automotive AC Bulletin Board
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