Yesterday morning I heard a noise coming from my A/C compressor and thought, "Oh, I'll have to look at that later". On my way home, the noise got louder and louder and I noticed a pretty significant decrease in engine power when the compressor was active. One errand later, I tried one last time to turn it on and it killed the engine. I'm assuming that there was some massive internal failure inside the compressor that has caused it to bind up and refuse to rotate.

My question is this: obviously the compressor needs to be replaced to get it up and running again, but what is the process for replacing it (draining the lines, flushing the system, things like that)? How do I make sure any debris is removed from the rest of the system? Is this a job best left to a repair shop or is it something I could tackle on my own? Also, does anyone have an estimate for what it should cost (parts AND parts/labor)? It is a 2003 Blazer 4WD.

 

You are going to have to replace the filter/dryer, the orifice tube, then while everything is apart flush the condenser & lines really well to remove the bits of the compressor that were released as it seized. If you find that the orifice tube screen is damaged to the point where it tore open, you'll need to flush the evaporator as well as the return lines to the compressor. This is a big job for a DIY'er in a driveway BTW! It all starts with getting the refrigerant recovered by an authorized repair shop.

 

Unless you have the right tools for this, i would take it to a shop. With a comp. failure like that, you are going to need to replace the filter dryer, i would replace that anytime an ac system is opened up. I keep reading people post about an oriface tube....not for sure on that, that is just a metering device that drops the pressure of the refrigerant and flashes some of the liquid refrigerant to vapor before the evaporator. It is likely that acid ( cant remember exactly what kind of acid) has contaminated the system when the comp failed. you might need to run an acid remover thru the system. after the comp. has been changed, you will need to do a nitrogen sweep to help clean out any debris in it, also do a press test with nitrogen. pull it into a vacuum and charge. my personal pref. on charging is to get a good amount of refrigerant into the system first, start the vehicle and have the ac on, put a thermometer in a vent inside the vehicle, over a period just add a shot of r134a until you see that the temp has droped to its lowest temp. and when it raises even 1 deg. stop there, then you know that the ac is running at its top effeincy. hope this helps, just graduated from a HVAC/R school and got certified to do all types of ac repairs.

 

This is called a "critical charge". This procedure is used to charge residential and commercial A/C systems when the refrigerant charge weight is unknown. This procedure should NEVER be used in automotive, especially CCOT, (Clutch Cycling Orifice Tube) systems. The exact amount of refrigerant has already been calculated and is usually noted on a label under the hood.

The compressor runs constantly on residential and commercial systems. Evaporator pressure is controlled with a valve allowing temperature to remain relatively constant. The compressor cycles on CCOT systems. Evaporator pressure varies from ~22psi to ~42psi during the cycle. Metering is done with a fixed, (stationary) orifice tube. CCOT evaporator temperature varies between ~22 degrees and ~42 degrees during each cycle of the compressor, (under optimum conditions).

The HVAC/R is residential, automotive systems are a totally different ball game

 

Did not know that....thanks for the info. about that. But between me and my dad, we haved charged several of our vehicles and familys vehicles with the method i mentioned. Its worked out great so far. I do see where how you explained it would make it not a good choice. Had no idea the comp. cycles on and off on car A/C's. Got to learn something new today...