Engine Size: 5.7
Refrigerant Type: 134A
Country of Origin: United States
I am replacing all the hoses, condenser,orphis tube, and accumulator on my A/C system. The condenser is just about totally blocked. The orphis tube has brown sludge built up on it. I flushed out the evaporator and there was no sign of any sludge or contaminants - just oil. When I removed the accumulator and drained out the oil, the oil was clean with no signs of contaminants.
My questions are these-- When I drained the oil out of the compressor I noticed that the oil was dark green ( There is Castrol green PAG-150 leak detection oil in the system). I then put some PAG-150 oil that was light-blue in color in the compressor and drained it out - as to flush out the compressor with clean oil and to see what discolored the green oil. When I drained the fresh "flushing oil" out, I noticed very tiny metallic particals in the fresh oil. The oil was a little darker, but not too much..Is this a sign of compressor failure or is this normal wear and tear? Also, the plastic on the pressure switch in the compressor itself seems to have melted a little. The o-ring that seals this switch is fine and has not failed.. What would cause this?
I have a 98 Chevy Tahoe with a 350ci engine..
What is your reason for doing all this work? What was your original failure mode? If just a leak- then there was no need to flush- just fix the leak and recharge-- was coompressor pumping good prior to disassembly? What were your pressures with a full charge prior to tearing into it?
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
With a blocked condenser you would have had high head pressures (excessive load) and poor oil migration (lack of lubrication). The fine metals and the melted pressure switch support this as evidence of compressor overheating. If you are going through all this trouble and parts replacement; add a NEW compressor. Brown sludge on the OT and blocked condenser; sealant?
The air was starting to get warm. I checked the pressures and they were - 45psi on the high side and 95psi on the low side. Not good.
The compresser was working fine - no knocking - no noises - it just stopped shortly after checking the pressures. That is when I decided to see what was up with the system.
I did weigh the refrig.- it was a little over 2 lbs. However I got about 13 ounces of oil out of the system - that is how much I actually recovered from the compressor/lines /evaporator/and a little from the condenser - that is not including the 3oz or so left in the accumulator...The factory spec calls for only 8 ounces...
There was no leaks in the system - that I am aware of...No lines were broken or cracked etc...
I did not disassemble the compressor, I just drained the oil out -then flushed it with fresh oil.. When I turn the compresser by hand, it spits out oil - and it turns freely - with no "hang ups" or "squeeks".
I am not an air conditioning pro. as you can probablly tell, so please bear with me. I am considering a new compressor (being that I am replacing everything but the evaporator), but I want to learn from this -- I don't just want to replace everything with new parts and say I fixed it. I want to know why it failed, and that is why I am asking you guys...
I want to salvage or sell the compresser if it is at all possible that the compressor is still good..Is there a way to test it?
Edited: Tue August 11, 2009 at 5:02 PM by thepear
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