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AC evacuate, dryer, orifice tube replace & recharge


brmurph

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 I have a leaking charging port on the dryer and will be replacing the dryer, orifice tube  and recharging.  I have a shop that has offered to evacuate the system for free (thought that was pretty nice) and I will be changing the parts and recharging it myself (using a manifold set)  but have a couple of questions.

1. How much Pag oil to put in?  I know the book says the accumulator holds 3 oz, should I just add in 3 ounces and call it good or should I try and measure the oil that is in the old Dryer and if so how do I do that (just pour and measure)?  Do I need to worry about adding more then the 3 oz the dryer holds.  

2. Best way to add the oil?  Should I just poor it into the dryer and if so does should I add it on the input or output?  

3. System holds 2 lbs of R134, Short of buying a scale (which I really don't want to do) how do  I put exactly 2 lbs in (I have heard R134 is more picky a bout this then R12 was)?

4.  Tricks to get the AC as cold as possible?

Any other suggestions for someone who has not done a full charge in 30 years (and that one didn't work that great, not too cold) would be appreciated.   BTW Autozone  ( I know not my favorite auto store for parts) has the gauges and vacuum pump to loan. 

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KHE is the AC expert he will be by.

My new ACDelco/Delphi compressor had oil in it if I recall.  I think KHE recommended that I drain it and measure how much was in it.  

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As for the scale, I tried using a bathroom scale that measured in 10th's of a  pound, but was not nearly accurate enough or real time. I ended up over charging it, and immediately removed the freon and ordered a postal scale, that could weigh as the freon exited the tank. I am very happy I did. Accuteck, arrived in two days, 23.99.

I'm hardly and expert, but do burp the line (let a small amount of freon out) at the nearest point to port that you can, to keep any air in the hoses out of your system.

I started with all new system on mine so measured the 9 oz and filled the compressor, however as I attempted to attach the lines, oil got out!, so I guessed at the amount and added 2 oz through the line at the dryer.

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I would add 3 ozs. PAG oil to the new accumulator.  You'll never get all the oil out of the old accumulator since much of it is saturated in the desiccant.  If you were replacing the compressor, then you would need to measure the quantity of oil drained from the compressor and add new oil to the compressor with the balance in the accumulator per the shop manual.

Are you using cans of R134a or a 30 pound cylinder?  If you're using cans, you will need to burp the air from the charging hose between cans.  If the manifold gage set you're using has a Schrader valve where the hose to the refrigerant container hooks up, it is easy.  If not, all you need to do is loosen the threaded hose connection at the gage manifold until a little refrigerant escapes, then tighten it up.  You don't need to mess with the low side hose that connects to the accumulator as it will be evacuated when you run the vacuum pump and it will have refrigerant in it when you close the valves to change cans.

Three 12 oz cans of R-134a will be close enough since you'll lose 1/2-1 oz of refrigerant each time you change the cans and burp the supply hose.

If you're using a 30 pound cylinder, you will need a scale - set the cylinder on the scale, burp the supply hose, then zero the scale.  Then charge the system until the scale reads 2.0 lbs.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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OK Thanks guys.    I am using 12 oz cans.   I guess you can't burp (or maybe no reason to burp because of the vacuum) the first can of refrigerant?  Also just found out there are different types of Pag oil, of course the parts counter person said either would work but said pag46 is the one for my car so that is what I bought, does that sound right (98 Deville Concours).

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The factory dryer cam with 5 o-rings, non of which look correct, to thin (look close for the dryer lines but seem a little big, I could be wrong), to  thick and 1 small o-ring.    Can anyone let me know which is for what?  I am tempted to use the old ones but hate to that. 

Also here is a pic of the orifice tube http://s265.photobucket.com/user/brmurph/media/Deville/20160901_114032_zps6pszc0g4.jpg.html?sort=3&o=1 (total of 4 pics) was hoping for better but is what I expected (one of the reasons I took this apart myself was to see how bad the orifice tube was).  Is this normal or is the compressor shot?

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5 hours ago, brmurph said:

OK Thanks guys.    I am using 12 oz cans.   I guess you can't burp (or maybe no reason to burp because of the vacuum) the first can of refrigerant?  Also just found out there are different types of Pag oil, of course the parts counter person said either would work but said pag46 is the one for my car so that is what I bought, does that sound right (98 Deville Concours).

If you are using a short charging hose, it will still be a good Idea to burp the air from it since your center (yellow) hose will be connected to the vacuum pump.  Once you connect the short charging hose to the low side port, there will be a small amount of air in the hose.

I believe you need 150 viscosity PAG oil (high viscosity.  You purchased low viscosity oil) for that car but double check the labels under the hood and post back the GM part no. it references for the oil and I can double check.

I don't know at what point they started using the low viscosity oil so you may be OK but it is best to double check.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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P/N 12345923 is for high viscosity (PAG-150) oil.  The 12345923 is a discontinued part number.  It would be interesting to see what number superseded 12345923 and go from there.  If it was 12378526, that is low viscosity (PAG-46) oil.

Usually, the Delphi/Harrision compressors needed PAG-150 and the Denso compressors used PAG-46 oil.

The orifice tube has some crud on it but it's not plugged.  I'd install a new one when you re-assembled the system.  It might not hurt to flush the line from the orifice tube to the condenser.  Don't attempt to flush through the condenser - you'll never get all the flush chemical out.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I am pulling my vacuum checking for leaks (connected blue line to the line/charging port that is close to the dryer input), red line to high side port, yellow line to vacuum pump and I see oil in the manifold/gauges site glass.  I assume it is sucking the oil out that I poured into the dryer?  I also assume this won't be good for the vacuum pump or keeping the correct level of oil in my system.    Am I doing something wrong here?

Thanks in advance.   

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23 minutes ago, OldCadTech said:

They should be oil filled gauges :)

I assume your saying that is normal?   It would not be the first time I have created a problem where there was none :blush:

That being said I did find some vacuum oil in the yellow line so I figured I shut the vacuum pump off without shutting the valves on the manifold first (at the time I didn't know you had too) and it sucked up some vacuum oil into the line (can this happen?)..    Anyway I took things apart just to verify I did not contaminate the system,  I was going to flush the metal lines again but I could plainly see the oil in the metal lines where green (factory PAG oil I assume)  and did not see anything that looked clear (vacuum oil).  I did run some pag oil through the yellow line to flush out the vacuum oil.      Anyway whatever I did it must have worked as the AC is colder then it has ever been in the 150,000 miles I have owned it :-)  

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  • 2 weeks later...

Its been a couple of weeks now so thought I would post my final results and note a few things.   One thing to note is that the dealer had just put a new compressor on under warranty less then 2000 miles ago, this is probably the 5th one they have put on over the last 10 years or so (I am assuming the condenser should be replaced one of these times :-).  I almost brought it back to the dealer as it wasn't that cold and the compressor rattles pretty good but I thought why not try to recharge it and see if I could get it colder then the dealer.    The final results are still good, the temperature at the vents average 5 or 6 degrees colder, it now stays under 50 degrees most of the time instead of above 50 (I know still not great but better then its ever been and I have had this vehicle since 2002, also I live in Austin Texas and the outside temp was about 95.   It kind of amazes me that I was able to get it colder then the dealer and they have had 5 shots at it.  The coldest I have seen since the recharge is 43, previously the coldest was 46 and this last compressor replacement it would not get that cold.  .  

I could not figure out how to burp the hoses without loosing a vacuum using the manifold gauges so I just used my cheap and short charging hose (easy to burp since it did not have a vacuum on it).    I could not match any of the new o-rings to the old ones, I even had an o-ring assortment kit but none of them looked right to me so I reused all the old O-rings.   I did flush the line as KHE suggested above (from condenser to orifice tube). I moved the vacuum pump from under the hood to the ground, shut off the high side valve (there was some evidence of pag oil being sucked into the high side hose of the manifold set) and ran  a vacuum for 3 hours, I had better luck keeping the vacuum oil out of the gauges (nothing in the site glass) but some still seemed to drain out of the yellow hose after I disconnected everything (if anyone knows why this is happening please let me know).   I used just under 3 cans of R134,  I stopped just a little early on the 3rd can (I figured I could always add more if needed).    I did add an extra ounce or two of oil (I used pag 150 ) in hopes of helping with the rattle (total of about 5 ounces added to the input of the dryer), I think it helped a little, obviously the extra oil did not effect the cooling. 

One other thing to note:  during the charge I could not get the vent temperature under 60 degrees (at idle), I was a little bummed out thinking I had made it worse then it was.  Well once I started driving the vehicle it did much better, usually between 47-52 when stopped at a stop light for any length of time (down from about 56-58 before the evacuate and recharge).

Oh and thanks to Autozone who loaned me all the tools for free (vacuum pump, manifold gauges, flush tank, orifice puller).  I was impressed!

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I recently recharged one of my vehicles and currently Home Depot has the r-134a cans for 6 dollars and change.  Although buying 3 cans will cost you 50+ dollars you get $30 back for the empty cans. 

 

$6.97 @ Home Depot

 

This is in bay area so your mileage may vary.

 

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You evacuated the system for 3 hours, I wonder if that was the reason why your AC is working so well?, pulling a vacuum for that length of temp certainly pulled all moisture out.  I am looking forward to what KHE says here.  

Most shops won't pull a vacuum that long, you may have uncovered something.  

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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The longer the vacuum is pulled, the better for the system but there is a limit on the time vs. effectiveness of the vacuum.  I usually pull a vacuum for one hour - another two hours wouldn't make that much difference in the performance of the system.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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