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Flush AC System


Scotty

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I am in the process of ordering the following from ACSource.com

8 ounces of PAG OIL ISO 46 low viscosity (called caddy dealer and they told me ISO 46 was on their shelf and that is what they use)

Measuring Cup

Nylog BLUE

and a Flush Gun http://www.acsource.com/index.asp?PageActi...PROD&ProdID=137

Will the flush gun work OK to purge my system of the OLD oil? I am flushing all the oil out as I am not sure if there is enough oil in the system and or whether or not TOO MUCH is in it, so I thought I would flush ALL the OLD OIL out and install all new OIL in the correct amount. I am replacing the compressor and the accumulator and will put the right amount of oil in those components. Where would I put the remaining oil. Also will I need new O-RINGS for the evaporator? I plan to flush the lines and the evaporator and replace the compressor and accumulator. Anything else need flushing? Can someone confirm my thinking. Any help or tips appreciated. Is 8 ounces of PAG oil enough? Mike

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That flush gun will work just fine. You might need to refill it a few times. You can buy A/C flush solvent or use mineral spirits. Some use lacquer thinner but you need to be very careful not to let it come in contact with any painted surface and it is extremely flammable.

I would replace the orifice tube as well since you need to remove it to flush the evaporator. If the condenser is a parallel flow design, it may prove difficult to flush. You could remove it and lay it flat so the flush doesn't run right to the bottom. As long as your compressor did not throw metal shavings in the system (you would see shavings in the orifice tube), you should be safe to reuse it.

I called my local Cadillac dealer and they stock only HIGH viscosity refrigerant oil....I can check the shop manual this evening and confirm high or low viscosity.

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

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That flush gun will work just fine. You might need to refill it a few times. You can buy A/C flush solvent or use mineral spirits. Some use lacquer thinner but you need to be very careful not to let it come in contact with any painted surface and it is extremely flammable.

I would replace the orifice tube as well since you need to remove it to flush the evaporator. If the condenser is a parallel flow design, it may prove difficult to flush. You could remove it and lay it flat so the flush doesn't run right to the bottom. As long as your compressor did not throw metal shavings in the system (you would see shavings in the orifice tube), you should be safe to reuse it.

I called my local Cadillac dealer and they stock only HIGH viscosity refrigerant oil....I can check the shop manual this evening and confirm high or low viscosity.

Kevin, thanks for the information regarding the LOW and HIGH viscosity PAG oil. THAT issue now makes me nervous as to whether LOW or HIGH is utilized. Anything you can find out about this issue I appreciate. I will hold my order till tomorrow. My intent as I mentioned was go blow out all the old OIL, do you think I should remove the evaporator to blow it out IF I DON'T find any debris in the orifice tube, and assume that it contains the correct amount of oil? I did purchase a new orifice tube also. I will order an additional quart of Fast Evaporating Automotive Air Conditioning Flushing Fluid from ACSOURCE, Thanks, Mike

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I'll look it up in my '96 shop manual this evening and post back. There is also a guideline of how much oil to add to the compressor, accumulator, etc.

If you don't find any shavings in the old orifice tube, then I would be inclined to leave the condenser alone. The evaporator can be flushed while in the vehicle - no need to remove it. Besides - the evaporator is a royal PITA to remove....

I've used mineral spirits as a flushing agent with good results. After flushing, blow each component out with dry compressed air (empty the flush gun and charge it with air). When you have the system evacuated, any residual flushing agent will quickly flash off and be removed by the vacuum pump.

If you are flushing only to remove the old oil to start with the proper quantity, you might be going through a lot of work unnecessarily as most of the oil is stored in the accumulator and the compressor. True, a small quantity will remain but the vast majority will be in the compressor and accumulator and you're replacing both.

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

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FWIW, I drained the oil from my Delco rebuilt compressor. I was suprised at the condition and crap in the oil, considering it was rebuilt by Delco, and shipped full of oil. It had shipping plugs installed in the ports. When I removed them, it hissed (like opening a vac-packed product), leading me to believe that the plugs were never removed since it was rebuilt. I filled it with fresh oil and turned it SEVERAL times. I drained out that oil, to see some more crud. I filled it again and turned it. This time the oil came out as clean as it went in. I then put in some fresh oil. Maybe get a Quart of oil, if you want to give your unit the final flush, so you know that it's clean inside. I used oil, instead of solvent, just to be on the safe side.

rek

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Always use oil to flush a compressor. rek, I'm surprised that your rebuilt unit contained oil. Usually, they're not shipped with oil due to PAG oil's ability to absorb water.

Mike,

I looked in the 1996 Cadillac shop manual and all it lists for oil is "Use GM P/N 12345923 or equivalent". It mentions that multiple times but fails to give the viscosity. I would stop by your Cadillac dealer and ask for a can of part no. 12345923 and see if it lists the viscosity. Post back your findings.

Below is the amount of oil to add when replacing components (without flushing and starting from scratch)

Compressor assembly replaced: If less than 1 oz, add 2 oz to compressor suction port. If more than 1 oz is drained, add the same amount to the suction port.

Accumulator assembly replaced: Add 1 oz more than what was drained from the old accumulator assembly.

Evaporator replaced: Add 3 oz oil.

Condenser replaced: Add 1 oz oil.

The manual states to add the oil directly to the component being replaced if possible. If the oil cannot be added to the component easily, add it to the accumulator. If you do wind up flushing, I would add the required amount to the compressor and dump the balance in the accumulator.

Torque values:

Nut at rear mounting bracket to compressor: 23 ft-lbs If stud comes out, its torque value to the block is 18 ft-lbs.

Two mounting bolts at front of compressor: 35 ft-lbs

Refrigerant pipe manifold block to rear of compressor: 24 ft-lbs

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

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i did pretty much the same job a couple of months ago replaced compressor ,accumalator, orifice tube flushed evap and condesor.I also replace all o-rings in the system and the hose assembly.The hose assembly was replaced because the factory manual specified that it cannot be flushed due to the muffler and fine mesh screens inside .With the system being Converted back to R-12 i didn't want to take any chances.Not sure if yours is the same but at least replace all the o-rings.

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Always use oil to flush a compressor. rek, I'm surprised that your rebuilt unit contained oil. Usually, they're not shipped with oil due to PAG oil's ability to absorb water.

Mike,

I looked in the 1996 Cadillac shop manual and all it lists for oil is "Use GM P/N 12345923 or equivalent". It mentions that multiple times but fails to give the viscosity. I would stop by your Cadillac dealer and ask for a can of part no. 12345923 and see if it lists the viscosity. Post back your findings.

Below is the amount of oil to add when replacing components (without flushing and starting from scratch)

Compressor assembly replaced: If less than 1 oz, add 2 oz to compressor suction port. If more than 1 oz is drained, add the same amount to the suction port.

Accumulator assembly replaced: Add 1 oz more than what was drained from the old accumulator assembly.

Evaporator replaced: Add 3 oz oil.

Condenser replaced: Add 1 oz oil.

The manual states to add the oil directly to the component being replaced if possible. If the oil cannot be added to the component easily, add it to the accumulator. If you do wind up flushing, I would add the required amount to the compressor and dump the balance in the accumulator.

Torque values:

Nut at rear mounting bracket to compressor: 23 ft-lbs If stud comes out, its torque value to the block is 18 ft-lbs.

Two mounting bolts at front of compressor: 35 ft-lbs

Refrigerant pipe manifold block to rear of compressor: 24 ft-lbs

Thanks Kevin, I will do that this morning the Caddy dealer is around the corner. I would buy it from them but the smallest amount is 20 ounces, a life time for me, and it would probably have too much moisture in it the next time I use it. Thanks for the information.

If I don't see any filings in the orifice tube I won't flush the system, only my hub assembly failed which overheated the clutch and shorted it. I ordered a Goodyear Gatorback Poly V belt yesterday also. Thanks for the information on the oil refills, I will follow that exactly. Will report back this morning regarding the viscosity. Mike

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Kevin, I can not tell you how PO'd I am right now. I went to my local Cadillac dealer and they INSISTED that part number 12345923 was obsolete and they NOW used part number 12378526 which states that it is 46 PAG Viscosity. They told me that they use it for ALL Cadillac systems now and its approved by GM! So I bought an 8 ounce tube for $29.00!

This contradicts what you told me above that HIGH viscosity is used and contradicts this site:

http://www.rtitech.com/Oil%20Chart%20-%20Compressor.pdf that states that 150 is used..... What the hell is going on here? I am afraid that if i use LOW viscosity my compressor will be LOUD and FAIL sooner. I plan to return this LOW viscosity PAG oil and order synthetic PAG oil 150 viscosity from www.acsource.com. What do you think now? Thanks for all your help, Mike

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I just entered part no. 12345923 in gmpartsdirect.com and it placed part no. 12378526 in my cart. Hmmmmmm.......

I called the Cadillac Dealer that is 2 miles from my office and he had two bottles on the shelf of part no. 12345923. He said that part no. was not superceded by any other part no.

I asked him if the bottle said anything about the viscosity index and he read right off the container, "High viscosity index". Translation 150 viscosity.

I would return the low viscosity stuff and buy an 8 oz. bottle of PAG 150 from your nearest auto parts store or acsource.

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

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Scotty I read somewhere that ester oil being a synthetic oil it is compatable with both 525 and pag. Also only use the 525 mineral oil on the fittings. Now Im not sure if all this is true or not! Taking a guess I would assume the synthetic oil to be better than both the 525 and the pag. (525 is the oil gm uses in my 89 camaro r4, a r12 system. Now also taking a educated Spock type guess I would assume that pag is used in 134a systems. Taking in all the terrain vector variences and time warp anomilies and adding the sub atomic particles along with the preponderence of carbon base matter I can only only assume that my guess would be correct. Mike

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I just entered part no. 12345923 in gmpartsdirect.com and it placed part no. 12378526 in my cart. Hmmmmmm.......

I called the Cadillac Dealer that is 2 miles from my office and he had two bottles on the shelf of part no. 12345923. He said that part no. was not superceded by any other part no.

I asked him if the bottle said anything about the viscosity index and he read right off the container, "High viscosity index". Translation 150 viscosity.

I would return the low viscosity stuff and buy an 8 oz. bottle of PAG 150 from your nearest auto parts store or acsource.

I agree Kevin.... this has become too confusing! I am going to buy the Castol PAG 150 from acsource and I dont think I can go too wrong with it. One more question when I replace the orifice tube will I need any o-rings? Does your manual point out where the orifice tube is? Thanks again, Mike

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Scotty I read somewhere that ester oil being a synthetic oil it is compatable with both 525 and pag. Also only use the 525 mineral oil on the fittings. Now Im not sure if all this is true or not! Taking a guess I would assume the synthetic oil to be better than both the 525 and the pag. (525 is the oil gm uses in my 89 camaro r4, a r12 system. Now also taking a educated Spock type guess I would assume that pag is used in 134a systems. Taking in all the terrain vector variences and time warp anomilies and adding the sub atomic particles along with the preponderence of carbon base matter I can only only assume that my guess would be correct. Mike

If my replicators were working I would just replicate part number 12345923 and be done with it. I even tried contacting the FERENGI to see if I negotiate for some 12345923 but they were fresh out... GM in my part of the quadrant (Long Island) has not been to helpful with this problem... Thanks, Mike

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The strange part is that your local dealer says 12378526 superceds 12345923 and the gmparts direct seems to confirm that BUT my dealer said that 12345923 is still a valid number. If it were superceded, the new part no. would appear on the screen as well as the obsolete no. Can they show you a TSB that changes the viscosity to 46???

The orifice tube is in the high pressure line to the evaporator (by the firewall) There will be an o-ring at the line connection. The orifice tube has an o-ring pre-installed. The short end of the tube is installed toward the evaporator and the long end toward the condenser. Coat the orifice tube o-ring with nylog prior to installation.

The Castrol PAG-150 oil should work just fine. I would not use ester oil in your application.

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

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The strange part is that your local dealer says 12378526 superceds 12345923 and the gmparts direct seems to confirm that BUT my dealer said that 12345923 is still a valid number. If it were superceded, the new part no. would appear on the screen as well as the obsolete no. Can they show you a TSB that changes the viscosity to 46???

The orifice tube is in the high pressure line to the evaporator (by the firewall) There will be an o-ring at the line connection. The orifice tube has an o-ring pre-installed. The short end of the tube is installed toward the evaporator and the long end toward the condenser. Coat the orifice tube o-ring with nylog prior to installation.

The Castrol PAG-150 oil should work just fine. I would not use ester oil in your application.

Kevin, I dont think they really care what the correct number is. I am sure you are correct about it NOT being superceded and that 12345923 is the correct OIL... So to hell with them, I bought Castrol PAG 150 for half the PRICE! I had someone tell me that MAYBE GM has changed the SPEC from 150 to 46, but I highly doubt that... I wonder how many systems they have screwed up using 46 when 150 is required?

I will look in the new orifice tube package to see if they put a new O-RING in the package for the in-line connection. If not, I will see if GM can handle selling me a simple O-RING!! My order with ACSOURCE was just confirmed I got 2 day delivery so I can get the work done over the weekend. Thanks, Mike

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You should be able to get the o-rings from the dealer or any auto parts store. I bought a GM o-ring assortment awhile back because I got tired of making a trip to the dealer to match up my old o-rings. Most of the time, the dealer parts guys wouldn't even charge me for the o-rings but the convenience of having the assortment in my A/C toolbox was worth it.

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

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You should be able to get the o-rings from the dealer or any auto parts store. I bought a GM o-ring assortment awhile back because I got tired of making a trip to the dealer to match up my old o-rings. Most of the time, the dealer parts guys wouldn't even charge me for the o-rings but the convenience of having the assortment in my A/C toolbox was worth it.

Yes I know what you mean, I should buy an assortment myself including a general o-ring assortment. Maybe I am being too harsh on the part's department, they have always been very helpful in the past. Its just that something like this is important enough for them to have and dispense the correct information regarding one of their part numbers. To simply tell me that, PAG ISO 46 is 'what all the guys are using now' is an inadequate answer given that the original part number 12345923 is HIGH Viscosity ISO 150. Not to provide reasoning for this GROSS change in specification to me is unacceptible, like a Service Bulletin explaining their change in thinking! By the way, I confirmed this issue with the service manager, he said, if that is what they are dispensing that is what we USE! WOW, talk about circular logic! Parts says, "ALL THE GUYS USE PAG 46", and SERVICE MANAGER says, "IF PAG 46 IS WHAT THEY ARE DISPENSING"! I wonder how many customers have had their cars repaired and the wrong oil was utilized? Sorry Mr. Smith it was your COMPRESSOR again, that will be $1,000. The customer of course thinks, man Cadillacs suck! I am sure I am being too tough on them and there is a logical explanation, like it really doesn't matter ISO 150 or ISO 46 and I'm being PICKY!!!! Now I have to go back and return the OIL, I hope he does not ask, WHY (darn)...

Who knows maybe ISO 150 is good for new installations and but ISO 46 is OK for older systems, but I doubt that. And your dealer had two tubes of 12345923 on the shelf! This kind of stuff always happens to me, I ask too many questions and attempt to do it TOO right! ROFL! I'm losing my mind and hair here! Beam Me UP!

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Kevin, I got the NYLOG, ISO 150 PAG oil, a measuring cup, and technical AC manual yesterday from ACSOURCE. They are really fast in getting your order out to you, I ordered it on TUesday and it was delivered on Wednesday even though I did a 2 day air. I also got a GoodYear Gatorback Poly V serp belt. So I am ready for this weekend! I am also replacing the idler wheel and serp belt tensioner, so she should be nice an quiet! Thanks, Mike

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Nylog is great stuff - the connections will not leak with that stuff. It sort of reminds me of pine-pitch but not as thick. Have you made the appointment for evacuation and charging yet?

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

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Nylog is great stuff - the connections will not leak with that stuff. It sort of reminds me of pine-pitch but not as thick. Have you made the appointment for evacuation and charging yet?

I am planning to go to a local radiator shop monday morning to have it evacuated and charged, they want $150... Thanks, Mike

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