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Discussion Starter #21
The rear lines have never been reproduced and have been out of production for a while now so can be very hard to find if you need them. Hopefully you won't. I think the all the under hood lines related to the 6.5 and rear AC are the same deal so be careful when working on them not to damage anything.

I think the reason the rear seems to work better than the front is it uses a valve like the 60's systems used that is variable and larger than the orifice tubes so it can adjust for a less than optimal system and possibly pass smaller chunks.
With that in mind, am I better off leaving the dryer and o tube? The compressor did not fail, it only leaks. I don't want to risk breaking a line if I don't need to. It also looks to have a replacement compressor installed at some point. It has delphi on the label and I am pretty sure it left the factory with a delco.
 

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Discussion Starter #22

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Discussion Starter #23

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I will have to make a note about those rear hoses. Not too crazy of a price and likely a lot easier to install than hard lines and won't corrode at every bracket like the aluminum lines do.
 

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With that in mind, am I better off leaving the dryer and o tube?
Coming from the refrigeration world I would at least replace the dryer. The o tube I wouldn't worry to much about. Even though you pull a vacuum on the the system there might still be the tiniest amount of moisture in the system that your pump wont remove and cause major problems. A dryer is cheap insurance.
 

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The way I understand it is that everytime the AC system is opened, the dryer/accumulator have to be changed.
Not sure if that is a tale, though.
 

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The way I understand it is that everytime the AC system is opened, the dryer/accumulator have to be changed.
Not sure if that is a tale, though.
That is the "way the book" says to do it. Like I said before it is cheap insurance. In all honesty at work I do not always change the drier. With what I work on it depends on the repair I am doing. If I have to just replace a oring or gasket on a compressor I don't. This is due to being able to close off a valve and trap the refrigerant in other parts of the system not the compressor. If i have to remove all the refrigerant for what ever repair I will replace the drier.
 
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Discussion Starter #28
Another suburban AC question.

Is mixing PAG 46 and PAG 150 a problem? I can get some of it out in the old compressor and some in the dryer and replace it with PAG 150. My thinking is that since the oils are the same chemically the end result would be an oil with a viscosity somewhere between 46 and 150. If I get most of the old oil out I thin I can have the viscosity above 100. How have you guys addressed this issue. When I did my 96 I paid no attention to the oil type in the truck. I just replaced what came out with the same about of 150 and it is still working fine 2 years later.

The truck originally calls for PAG 46. The new delco compressor says to use PAG 150. The truck looks to have had the compressor replaced once with a denso compressor. I have no idea what oil came in that compressor.
 

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My fix and later I found out many shops also do it is to use ester 100. Its kinda a universal oil that plays reasonably well with other oils so you don't have to try and guess what was in there or worry about getting it all out.

Don't know why the oil thing is such a mystery most of the time. I have bought compressors new and rebuilt that have stickers and labels plastered all over them that says 'use the correct oil' or 'has 1 oz of oil in it check your owners manual to add the rest' but they never friggen seem to say what they put in there or what they recommend. I even got the store interested one time and they contacted the manufacturers of the compressors they carried and apparently didn't get an answer which seems really dumb since its really mostly the compressor that care what type of oil is used.
 

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IIRC, the higher the number the higher the viscosity.

I know when I did my Toyota with Denso Compressor (of course), it used PAG46.
I am not sure if there is any AC guy here that can chime in,
I know Thefermenator have a lot of experience with AC but he does not hang out here anymore.
 

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Discussion Starter #31
I need to give delco credit for shipping the compressor with no oil and a hard plastic plug bolted into the ports. Having no oil in the compressor means no oil balancing procedure and no guessing what oil it shipped with. I am going to start tonight and probably finish tomorrow. it takes time to do HVAC right.

As far as the universal oil goes. I have several HVAC mechanic friends. One swears by universal oil. The rest swear at him for using it. They have told me about how it can cause problems over and over again. It does have its place, but if the only difference is viscosity, mixing pag oils will not hurt seals.
 

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Discussion Starter #32
I replaced the compressor, dryer, o tube, and the all the o rings I exposed. It took around 58 oz of r134a. The high side was a little high and the low side a little low compared to before but it is cooling de3cently. I have not test driven it yet for a full test. The only thing that is concerning me is that the compressor clutch seems to drag when not engaged. It is making a squealing/scratching sound but when engaged it makes no sound. It also engages immediately. Should I return the compressor or let the clutch wear in a little?
 

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Interesting that you are not much over a front system for charge. How is the performance front compared to back?

Lucky for me AC season is over so I can put off fixing it for about 6 months again.
 
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