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| AC Diagnosis [message #221518] |
Sat, 07 September 2013 15:42  |
Manong
Messages: 88
Registered: July 2007
Location: Madison, WI
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Well, I got my GMC AC working and it blows great. So, I decided to try to fix my other motorhome which is a Coronado on a GMC chassis. I evacuated the R12 from the low side port and out came some stuff that resembled a white cream paste substance along with the R12. Don't know what it is ????
Evacuated it all out (I think) and did a vacuum on the system, vacuum held so it appears there are no leaks.
There are no high side ports anywhere along the high side lines. There is a low side service port on the line before it goes into the evaporator. On the back of the compressor where the lines go into the compressor there are two (what appear) to be ports one high and low. At least they both have shader valves in them.
Any way I vacuumed and put in a can of duracool and the compressor kicked in, so I put more in to bring pressure up to about 25 psi. I put an adaptor on the, what I think the high side is at the back of the compressor but I get no pressure reading. Also when I depress the other valve next to the high, which I think is the low, I also get no pressure. I do get pressure when I depress the valve that I feed the duracool in. I would think that if these two are a high and a low there should be pressure in each one.
The compressor in it is a SanDen SD 709 Model U7499.
Any way when I do the temperature reading the temp drops from the ambient of 80 to 69 as I rev the engine to 1500 and hold at 2000 rpm, so I think something is happening.
Is this a sign that maybe the compressor is failing since cooling occurs better as engine revs?
Manong
Madison, WI
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| Re: AC Diagnosis [message #221562 is a reply to message #221518] |
Sat, 07 September 2013 21:07  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
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Did mineral and PAG oil get mixed at some point causing the mystery substance? I'd think that would have to be flushed and replaced.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: AC Diagnosis [message #221566 is a reply to message #221562] |
Sat, 07 September 2013 21:45 |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
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| Quote: |
...... I evacuated the R12 from the low side port and out came some stuff that resembled a white cream paste substance along with the R12. Don't know what it is ????........There is a low side service port on the line before it goes into the evaporator.......
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I agree with John. That SD compressor probably had a mixture of incompatible lubricants. Some service ports have shut-off valves. Perhaps that's why there is not pressure on a couple of your ports. BTW high pressure goes into the expansion valve at the evaporator and low pressure comes out of the evaporator.
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: AC Diagnosis [message #221603 is a reply to message #221562] |
Sun, 08 September 2013 09:23 |
Manong
Messages: 88
Registered: July 2007
Location: Madison, WI
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| JohnL455 wrote on Sat, 07 September 2013 21:07 |
Did mineral and PAG oil get mixed at some point causing the mystery substance? I'd think that would have to be flushed and replaced.
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Don't know about the mixing of oils or refrigerant, but ever since I've had this motorhome the ac has worked somewhat on the poor side.
I did find as, Mr Sharp, mentioned, the shut off valves for ports. Yes that is exactly why no pressure was coming from the ports at the compressor. Opened the high side up, took a reading and it is only about 100.
Looks like I will need to get a new compressor. But since the creamy stuff came out, guess I'll have to flush the system also, replace expansion valve, and drier too. I was looking to see if I could find an enlargement in one of the lines for an orifice tube thingy, but don't see any size difference anywhere.
Could it be that there is none ??
Manong
Madison, WI
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| Re: AC Diagnosis [message #221614 is a reply to message #221603] |
Sun, 08 September 2013 10:08 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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| TL wrote on Sun, 08 September 2013 10:23 |
<snip>
Looks like I will need to get a new compressor. But since the creamy stuff came out, guess I'll have to flush the system also, replace expansion valve, and drier too. I was looking to see if I could find an enlargement in one of the lines for an orifice tube thingy, but don't see any size difference anywhere.
Could it be that there is none ??
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TL,
If the system has an expansion valve, then it does not have an orifice tube. They are the same function, but the orifice is cheaper and works like it is.
If you got out creamy stuff, that is either the original mineral oil that has gotten wet (then it decays) or a mix of mineral and PAG oil. Either way, it needs to be cleaned out.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: AC Diagnosis [message #222002 is a reply to message #221614] |
Tue, 10 September 2013 21:24 |
Manong
Messages: 88
Registered: July 2007
Location: Madison, WI
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Well, I found the high pressure port and put a guage on it and one on the low. I started to fill up with dura cool, things were looking good,pressure on low at about 25 and the high at about 150, then all of a sudden the low drops to a vacuum and the high drops to about 100. I took everything apart and I am flushing the system, put in new drier and expansion value. I think the compressor is still good so going to put it back in. I found no metal flakes and such in the compressor oil and the clutch turns ok. My problem is:
1. What type of oil should I use?
2. How much (for compressor and entire system)??
3. Is there anything else I should be considering?
Compressor is a Sanden SD-709 Model U7499 (no longer in production). But regardless I can find no one who will say what type of oil and how much I should use. Everyone wants to sell me the Pag oil, but even then what viscosity? The system capacity with the R-12 was 3.5 lbs.
So here I am again relying on the experts on this GMC forum, hope you can help me. 
Manong
Madison, WI
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| Re: [GMCnet] AC Diagnosis [message #222006 is a reply to message #222002] |
Tue, 10 September 2013 21:45 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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If you had R-12 in it before then you had mineral oil.
DO NOT mix PAG with mineral oil. It will react and you will clog up your system.
If you buy a compressor with PAG or ester oil installed you MUST drain it and fill with mineral spirits and drain again. good to repeat this a second time. Then put about 4 or 5 ounces in the compressor. The whole system holds about 10 ounces of oil but the condensor holds 1, the drier 1 and the evaporator 3. The hoses might have a little as well so that is how I arrive at 4 to 5 ounces in the compressor. Now, that is for the GM compressor. The Sanden might hold a little less but I am not sure. 4 ounces would seem about right. HOWEVER, you say you flushed everything out. In that case put in about 9 ounces of MINERAL oil with the Sanden compressor.
The system capacity of 3.5 pounds was not the oil, it was the amount of R-12.
If you use Duracool you want to put in about 3 cans which is 18 ounces.
Emery Stora
On Sep 10, 2013, at 8:24 PM, Tom Lopez wrote:
>
>
> Well, I found the high pressure port and put a guage on it and one on the low. I started to fill up with dura cool, things were looking good,pressure on low at about 25 and the high at about 150, then all of a sudden the low drops to a vacuum and the high drops to about 100. I took everything apart and I am flushing the system, put in new drier and expansion value. I think the compressor is still good so going to put it back in. I found no metal flakes and such in the compressor oil and the clutch turns ok. My problem is:
>
> 1. What type of oil should I use?
> 2. How much (for compressor and entire system)??
> 3. Is there anything else I should be considering?
>
> Compressor is a Sanden SD-709 Model U7499 (no longer in production). But regardless I can find no one who will say what type of oil and how much I should use. Everyone wants to sell me the Pag oil, but even then what viscosity? The system capacity with the R-12 was 3.5 lbs.
>
> So here I am again relying on the experts on this GMC forum, hope you can help me. :blush:
> --
> Manong T, 74 GMC Sequoia
> Madison/De Forest, WI
>
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| Re: AC Diagnosis [message #222007 is a reply to message #222002] |
Tue, 10 September 2013 21:56 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| TL wrote on Tue, 10 September 2013 21:24 |
Well, I found the high pressure port and put a guage on it and one on the low. I started to fill up with dura cool, things were looking good,pressure on low at about 25 and the high at about 150, then all of a sudden the low drops to a vacuum and the high drops to about 100. I took everything apart and I am flushing the system, put in new drier and expansion value. I think the compressor is still good so going to put it back in. I found no metal flakes and such in the compressor oil and the clutch turns ok. My problem is:
1. What type of oil should I use?
2. How much (for compressor and entire system)??
3. Is there anything else I should be considering?
Compressor is a Sanden SD-709 Model U7499 (no longer in production). But regardless I can find no one who will say what type of oil and how much I should use. Everyone wants to sell me the Pag oil, but even then what viscosity? The system capacity with the R-12 was 3.5 lbs.
So here I am again relying on the experts on this GMC forum, hope you can help me.
|
I don't know what kind of oil, the MM just says "refrigeration oil" but,
Per the 74 MM:
Add the full 10 fluid oz. of new refrigeration oil to the replacement compressor.
Add additional oil in the following amounts for any system components being replaced.
Evaporator core 3 fluid oz.
Condenser 1 fluid oz.
Receiver-dehydrator 1 fluid oz.
CAUTION : When adding oil to the compressor, it will be necessary to tilt the rear end of the compressor up so that the oil will not run out of the suction and discharge ports.
Do not set the compressor on the shaft end.
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| Re: AC Diagnosis [message #222018 is a reply to message #222002] |
Wed, 11 September 2013 03:23 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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A little clarification. Everything Emery states is true. That said, types of oil are determined by the refrigerant used.
R-12 used Mineral Oil
R-134 used PAG
Additional information:
Ester oil can be used with either r-12 or r-134
Duracool refrigerant can be used with any type of oil.
So now the most important statement: if you use Dur DO NOT MIX TYPES OF OIL.
Since Duracool will mix with any type of oil, you really need to determine what was in the system before, or thoroughly flush or replace ALL components of the system.
I believe Emery is assuming that you had an R-12 system with mineral oil before you started repairing it. If this is true, then do exactly as he said.
What bothers me is that Sandeen compressor. It is not OEM. So my question is: did someone in the past change it and install PAG, or Ester, or a mix of PAG, Ester, or Mineral oil? If so, then a total flush / replacement of all components is in order. After a complete flush the choice of oil to be installed is up to you IF YOU USE DURACOOL. IF you use a different refrigerant match the oil to the refrigerant. Label the system with whatever you use. I would probably use mineral oil.
I hope I did not confuse you more.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] AC Diagnosis [message #222027 is a reply to message #222006] |
Wed, 11 September 2013 07:58 |
Manong
Messages: 88
Registered: July 2007
Location: Madison, WI
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All these great answers made me think of a couple more before I do anything:
1. Do I drain and flush compresor with mineral SPIRITS or Oil?
2. Brand, viscosity and where to buy mineral oil ?
3. After reading more about Sanden I agree with 9 oz for entire system. Do I put all 9oz into compressor and let it disperse the oil out into the system ?
Ken had a question as to the sanden not being OEM. I believe he is right. When they built these Fleetwood motorhomes, from what I found out this is what they used plus others. This sanden compressor is an R12 compressor which had from factory suniso-5GS oil in it. The label does not however tell me how much. I believe since it is an R12 compressor that is mineral oil. Don't know if however at any point in time that someone else may have mixed anything or maybe the creamy stuff was just moisture and oil mix from being 21 years old with a leak allowing moisture in.
What is suniso-5gs oil and is it compatible with all mineral oil ?
[quote title=emerystora wrote on Tue, 10 September 2013 21:45]If you had R-12 in it before then you had mineral oil.
DO NOT mix PAG with mineral oil. It will react and you will clog up your system.
If you buy a compressor with PAG or ester oil installed you MUST drain it and fill with mineral spirits and drain again. good to repeat this a second time. Then put about 4 or 5 ounces in the compressor. The whole system holds about 10 ounces of oil but the condensor holds 1, the drier 1 and the evaporator 3. The hoses might have a little as well so that is how I arrive at 4 to 5 ounces in the compressor. Now, that is for the GM compressor. The Sanden might hold a little less but I am not sure. 4 ounces would seem about right. HOWEVER, you say you flushed everything out. In that case put in about 9 ounces of MINERAL oil with the Sanden compressor.
The system capacity of 3.5 pounds was not the oil, it was the amount of R-12.
If you use Duracool you want to put in about 3 cans which is 18 ounces.
Emery Stora
Manong
Madison, WI
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| Re: [GMCnet] AC Diagnosis [message #222033 is a reply to message #222027] |
Wed, 11 September 2013 08:57 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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Flush it with mineral spirits (or naphtha).
Just go to an auto parts store (NAPA has it) And ask for mineral oil for an R 12 system. I doubt they carry more than one viscosity. Brand shouldn't matter.
You can put all of into the compressor and
Emery
On Sep 11, 2013, at 6:58 AM, Tom Lopez <elitesdc@charter.net> wrote:
>
>
> All these great answers made me think of a couple more before I do anything:
> 1. Do I drain and flush compresor with mineral SPIRITS or Oil?
> 2. Brand, viscosity and where to buy mineral oil ?
> 3. After reading more about Sanden I agree with 9 oz for entire system. Do I put all 9oz into compressor and let it disperse the oil out into the system ?
>
> Ken had a question as to the sanden not being OEM. I believe he is right. When they built these Fleetwood motorhomes, from what I found out this is what they used plus others. This sanden compressor is an R12 compressor which had from factory suniso-5GS oil in it. The label does not however tell me how much. I believe since it is an R12 compressor that is mineral oil. Don't know if however at any point in time that someone else may have mixed anything or maybe the creamy stuff was just moisture and oil mix from being 21 years old with a leak allowing moisture in.
>
> What is suniso-5gs oil and is it compatible with all mineral oil ?
>
>
>
> [quote title=emerystora wrote on Tue, 10 September 2013 21:45]If you had R-12 in it before then you had mineral oil.
> DO NOT mix PAG with mineral oil. It will react and you will clog up your system.
> If you buy a compressor with PAG or ester oil installed you MUST drain it and fill with mineral spirits and drain again. good to repeat this a second time. Then put about 4 or 5 ounces in the compressor. The whole system holds about 10 ounces of oil but the condensor holds 1, the drier 1 and the evaporator 3. The hoses might have a little as well so that is how I arrive at 4 to 5 ounces in the compressor. Now, that is for the GM compressor. The Sanden might hold a little less but I am not sure. 4 ounces would seem about right. HOWEVER, you say you flushed everything out. In that case put in about 9 ounces of MINERAL oil with the Sanden compressor.
>
> The system capacity of 3.5 pounds was not the oil, it was the amount of R-12.
> If you use Duracool you want to put in about 3 cans which is 18 ounces.
>
> Emery Stora
> --
> Manong T, 74 GMC Sequoia
> Madison/De Forest, WI
>
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| Re: [GMCnet] AC Diagnosis [message #222034 is a reply to message #222033] |
Wed, 11 September 2013 08:59 |
Emery Stora
Messages: 959
Registered: January 2011
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You can put it all into the compressor and it will disperse it through the system.
Emery Stora
On Sep 11, 2013, at 7:57 AM, Emery Stora <emerystora@me.com> wrote:
> Flush it with mineral spirits (or naphtha).
>
> Just go to an auto parts store (NAPA has it) And ask for mineral oil for an R 12 system. I doubt they carry more than one viscosity. Brand shouldn't matter.
>
> You can put all of into the compressor and
> Emery
>
> On Sep 11, 2013, at 6:58 AM, Tom Lopez <elitesdc@charter.net> wrote:
>
>>
>>
>> All these great answers made me think of a couple more before I do anything:
>> 1. Do I drain and flush compresor with mineral SPIRITS or Oil?
>> 2. Brand, viscosity and where to buy mineral oil ?
>> 3. After reading more about Sanden I agree with 9 oz for entire system. Do I put all 9oz into compressor and let it disperse the oil out into the system ?
>>
>> Ken had a question as to the sanden not being OEM. I believe he is right. When they built these Fleetwood motorhomes, from what I found out this is what they used plus others. This sanden compressor is an R12 compressor which had from factory suniso-5GS oil in it. The label does not however tell me how much. I believe since it is an R12 compressor that is mineral oil. Don't know if however at any point in time that someone else may have mixed anything or maybe the creamy stuff was just moisture and oil mix from being 21 years old with a leak allowing moisture in.
>>
>> What is suniso-5gs oil and is it compatible with all mineral oil ?
>>
>>
>>
>> [quote title=emerystora wrote on Tue, 10 September 2013 21:45]If you had R-12 in it before then you had mineral oil.
>> DO NOT mix PAG with mineral oil. It will react and you will clog up your system.
>> If you buy a compressor with PAG or ester oil installed you MUST drain it and fill with mineral spirits and drain again. good to repeat this a second time. Then put about 4 or 5 ounces in the compressor. The whole system holds about 10 ounces of oil but the condensor holds 1, the drier 1 and the evaporator 3. The hoses might have a little as well so that is how I arrive at 4 to 5 ounces in the compressor. Now, that is for the GM compressor. The Sanden might hold a little less but I am not sure. 4 ounces would seem about right. HOWEVER, you say you flushed everything out. In that case put in about 9 ounces of MINERAL oil with the Sanden compressor.
>>
>> The system capacity of 3.5 pounds was not the oil, it was the amount of R-12.
>> If you use Duracool you want to put in about 3 cans which is 18 ounces.
>>
>> Emery Stora
>> --
>> Manong T, 74 GMC Sequoia
>> Madison/De Forest, WI
>>
>> _______________________________________________
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| Re: [GMCnet] AC Diagnosis [message #222048 is a reply to message #222047] |
Wed, 11 September 2013 13:04 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Compressed air is NOT DRY. All the water it contains before compression is
still in it. The mineral spirits forced through the AC system gets rid of
the oil you don't want. After you flush it, replace the dessicant /dryer,
and vacuum the system overnight. That will remove any trace of water. You
absolutely DO NOT want any residual water in the closed system. In
extremely humid areas of the country, 8 hours is not long enough, it takes
overnight or longer to insure. But, opinions vary, so do what you feel is
best.
Jim Hupy
Salem, Or
78 Gmc Royale 403.
On Sep 11, 2013 10:37 AM, "Tom Lopez" <elitesdc@charter.net> wrote:
>
>
> Thanks for the info about the oil. That makes me one step further. Now I
> have to figure out how to get dry air to finish the flush and/or nitrogen
> to dry the condenser, lines, and evaporator.
>
> 1. Where do you get nitrogen ?
>
> 2. Is there an easy way to get my small air compressor to blow dry air ?
>
>
> Flushed all those things, they seemed fairly clean. Not much debris or
> weird stuff. Didn't see any more creamy foam. Gotta dry all those things
> out now. :roll:
> --
> Manong T, 74 GMC Sequoia
> Madison/De Forest, WI
>
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| Re: [GMCnet] AC Diagnosis [message #222057 is a reply to message #222047] |
Wed, 11 September 2013 14:41 |
emerystora
Messages: 4442
Registered: January 2004
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TOM
Don't worry about dry air from your compressor. When you put the vacuum pump onto your system to evacuate it you will pull all of the moisture out. Just vacuum it for an hour or so.
And, don't worry about the brand for the mineral oil that you buy. If it says mineral oil on the bottle and it says its for R12 it will work fine.
Emery Stora
On Sep 11, 2013, at 11:37 AM, Tom Lopez wrote:
>
>
> Thanks for the info about the oil. That makes me one step further. Now I have to figure out how to get dry air to finish the flush and/or nitrogen to dry the condenser, lines, and evaporator.
>
> 1. Where do you get nitrogen ?
>
> 2. Is there an easy way to get my small air compressor to blow dry air ?
>
>
> Flushed all those things, they seemed fairly clean. Not much debris or weird stuff. Didn't see any more creamy foam. Gotta dry all those things out now. :roll:
> --
> Manong T, 74 GMC Sequoia
> Madison/De Forest, WI
>
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| Re: AC Diagnosis [message #222062 is a reply to message #221518] |
Wed, 11 September 2013 15:10 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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We are assuming the MH was built before R134a so that's why the manual doesn't specify. Everything was R12 then with about 1994 being the transition period.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: AC Diagnosis [message #222076 is a reply to message #222064] |
Wed, 11 September 2013 20:22 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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You also can get mineral oil at any HVAC supply store. It is used in home R-22 AC systems.
Or... flag down any heating and air conditioning truck you see and he should have some.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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