Engine Size: 5.7L
Refrigerant Type: r134a
Country of Origin: United States
I'm going to be fixing the AC on this vehicle for some of my fiancee's relatives. They have taken it to a couple of shops where one told them the compressor is leaking and it will be $1,200 to fix it and the other shop said the compressor is not leaking and recharged it and now its not cooling again. This shop replaced the low pressure cycling switch and the switch on the high side of the hose manifold.
I looked under the hood and could immediately tell the compressor has been leaking. Extremely dirty and oily and bracket underneath the compressor is wet. Truck has 168,000 miles on it and it looks to be the original compressor. I have a couple of questions about repairing this vehicle.
I don't think its had a catastrophic compressor failure so I'm hoping it doesn't have a lot of debris in the system.
I'm not familiar with the duel air systems on this vehicle. I have done two 98 C/K trucks but these were my own vehicles and I replaced most of the AC systems to avoid problems down the road. I don't know how much they want to spend on parts so replacing some things may not be an option.
1. For just a leaking compressor, what other than the compressor, accumulator, and OT do I have to replace. All I have is a flush gun which is not very powerful.
2. Can this type of condensor be flushed and does it need to be if the OT looks pretty clean?
3. Manifold hose assembly. This set has the inline muffler so it cant be flushed. Does it need to be replaced or can it be reused?
4. What do I need to check on the rear air part of this system? I have heard that this part is hard to access and is usually rusted together.
5. This system takes 64oz of refrigerant and 11oz of oil. How much oil should I put in the system if I can't access the rear part of the system or if I leave the condensor in place?
Any other tips on fixing this system. On my own trucks I replaced everything in the systems other than the evaporater and line going from the condensor to the evaporater so I'm not sure what is acceptable to do if you don't replace everything. Thanks for any advice.
These are the ones I re-seal almost daily---All new belly o-rings and a new shaft seal-- for under $300---out the door...Got a 97 Blazer out there today with same issue.....
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......
Thanks for the reply. So on a system that only the compressor is leaking, you only repair the compressor and leave every thing else alone? Do you replace the accumulator and OT.? How much oil do you add back into the system.
When I go to recharge, do I need to have the rear system on max and the fan on high?. I'm very familiar with the front part of this system, just not the rear part. I really don't want to mess with the rear expansion valve or any of the rear plumbing if I can help it. How often do the rear expansion valves need to be replaced.?
They brought me the Sub today and I looked at it a little closer. The compressor is the only thing that looks like it has leaked. The owner is the original owner and says that the compressor has never been changed and did not make any noises. The odometer shows 122,000 miles on it but he says it has 168,000 miles on it so I'm not sure what is correct. Thanks for any other advice.
On my '94 Suburban dual air with a leaky compressor this spring, right or wrong I replaced only the compressor and accumulator with new. My rear expansion valve failed last year (clogged or stuck closed), but no big deal (even in Arizona) as the system cools great now. I replaced the accumulator because in my case the system had been without refrigerant for several months due to the leak (why fix in fall if a tree might fall on it and wreck it, it's only worth $2500). Since the compressor didn't seize or make any noises, and past experiences with replacing the orifice tube didn't show ANY particles, I didn't address that at all.
I did add full amount of R134a (64 oz.) even though the rear wasn't working, must fill the system (or physically block off the plumbing to the rear).
In the 10 years I've owned this 1994 Sub, the compressors have only lasted a few years each. They get used 95% of the time, but dual-air systems are just very tough on them, read GM Tech's TSB in other posts.
thanks for the info. How much oil did you add to the system for just replacing the accumulator and compressor.?
The owner said that the rear air worked fine before so I'm hoping that it still will.
Does both front and rear AC need to be on max when recharging?
The r134a capacity listed on the accumulator is 3lb 8oz, so 56oz. Should I stick with 56 or go to 64oz?
I ordered the replacement compressor, accumulator, OT, Pag oil, and some gaskets from Ackits today so hopefully I can get this fixed this weekend. I ordered the Seltec compressor but they called and said they didn't have it in stock so I got the Sanden one instead.
Cussboy, thanks again on the clarification for my questions. I'll start with the 56oz of refrigerant and go from there. I thought maybe later on, someone discovered that 64oz worked better.
The amount of oil has me most concerned since I'm hopefully not going to be tearing apart the entire system. I guess I will go with the 8oz you suggested unless someone gives me a good reason not to. There is no telling how much oil has leaked out from the compressor. The first time I looked at the vehicle, it was pretty wet under there. Not so much today.
I've heard that the Sanden compressor is one of the preferred replacements so I'm not worried about it. I've just used the Seltec in the past and have had good luck so far with them. Thanks again.
HA! Sounds like we're in a similar position:
I've got a 98 Yukon that I've worked on. I couldn't break the rear expansion valve loose and it was a royal pain to get to. I replaced the accum, comp, OT, and condenser. I opted not to flush the system since the OT was clean and I was replacing most of the components. If I remember correctly I charged 5 cans (60 oz) but more or less watched the readings as I neared the 5 can mark.
I know nothing...seriously
If you have front and rear air, your oil capacity is 11 ounce front air only is 8 ounces...
Freedoms just another word for nothing left to lose
Wayne - in mine the brand-new compressor (Delphi R4) contained no oil at all. For my '94 dual-air Sub I added an entire 8 oz. bottle of oil (which already contained some UV dye) to the compressor, then turned it about five revolutions by hand before installing the compressor.
I did all mine in one day, took about half day including the evacuation, vacuum hold test, adding the R134a. In my case, I did not have to "tweak" the R134a amount later.
Thanks again for your help. I just want to make sure I'm not putting too much or too little oil in the system since the only components I'm replacing are the compressor and accumulator and this system holds quite a bit of oil. I'm still undecided on replacing the condensor because I have not taken out the OT yet. I'm going to do that tomorrow.
I know the correct way to do this repair is take everything apart and flush but getting the back stuff all apart is probably asking for trouble. I don't want to risk ruining the rear lines if I don't have to. I know they are expensive.
I did get the old fan clutch off and mounted the new one to the fan blades but I will wait to install it after replacing the compressor since it gives me a lot more room to work with it off. Thanks again.
Well, I pulled the OT and the screens were as clean as a whistle. Actually, the cleanest one I have pulled. The OT itself didn't look new so I don't think its been changed. I don't plan on changing out the condensor or the lines now. I'm just going to replace the compressor and accumulator, pull a vacuum, and recharge.
If none of the other connections look like they have been leaking, should I just leave them alone and not put new o-rings in? I typically do replace all of the o-rings but this vehicle has a lot more connections than what I have typically worked on. I wasn't planning on messing with any of the rear connections, just the ones in the engine compartment.
I wouldn't mess with connections that weren't leaking and weren't disconnected.
I ended up replacing all of the O-rings because when I got to looking at some of the connections a little better, the two connections in the engine compartment that go to the rear air were very dirty and slightly oily. To get to those though, I had to disconnect the one line that goes into the lower part of the evap since it was on top of the two lower rear air lines.
I inspected all of the lines going under the truck all the way to the back and did not see any leakage. As long as both evaps are good, I'm probably ok.
Hopefully I will get the parts tomorrow so I can finish this up.
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