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What is the correct high/low pressure for an R12 system?

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    What is the correct high/low pressure for an R12 system?

    System totally vacumed clean. New reman compressor, new evaporator valve, new drier and filled up with the correct BMW Spec of R12 and Mineral oil.

    The problem is my low side pressure is 53

    What could the issue be?

    The compressor kicks on, the aux fan comes on.

    I am going to take the front grill off and the kidney off and use a fin comb in case there are any bent fins on the condenser and I am going to spray down the condenser to maybe clean it out. I am hoping this will help in the cooling problem I am having.

    #2
    Dude what the fuck is up with all these freon questions? The amount of freon you need in your car is on a label under the hood.

    The pressures will vary depending on the ambient temperature.

    The low side sound fine. 53 is a little high but not too bad. If anything you are overcharged but who knows. Whats your weather like?
    Ma che cazzo state dicendo? :|

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      #3
      53psi seems pretty damn high for low-side pressure. Couldn't hurt to clean the condenser.

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        #4
        Ambient of 80-90 at idle I shoot for 18-24lbs on the low side of r12.

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          #5
          average is 42 - 50 in the summer.
          Ma che cazzo state dicendo? :|

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            #6
            Originally posted by bimmerteck View Post
            Ambient of 80-90 at idle I shoot for 18-24lbs on the low side of r12.

            Am I really that off? Your stating 18-24 on the low side?

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              #7
              Originally posted by b*saint View Post
              average is 42 - 50 in the summer.

              Your saying 42-50lbs in the summer is average in the low side?

              I am surely not in the South Florida Summer I used to be. I am now living in Western North Carolina. low 80s to high 80's maybe peaking into the 90s.

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                #8
                Look guys, you can't just throw a gauge on a single spot in the system and expect to diagnose anything. You have to compare the high side pressures to low side pressures while evaluating both vent and ambient temps. Ambient isn't what the weather channel says today's high was either it's from a thermometer placed a few inches in front of the condenser.

                Yes, 50psi would be over what I normally see in R12 systems on the low side even at 110 degree ambient I doubt I've cracked 40. I had a vintage Mercedes wagon last month that was putting 30 degree air out the vents at 22psi on the low side and 185 on the high on an 85 degree day.


                I give all old R12 systems a full evac at a station down the road. I draw the system down using my 5cfm pump and charge r12 only from a 30lb cylinder and scale or sealed new cans. I never put reclaimed r12 into the cars and I never mix refrigerants. I assume your higher pressures are due to either atmospheric contamination or refrigerant contamination.

                Comment


                  #9
                  Originally posted by bimmerteck View Post
                  Look guys, you can't just throw a gauge on a single spot in the system and expect to diagnose anything. You have to compare the high side pressures to low side pressures while evaluating both vent and ambient temps. Ambient isn't what the weather channel says today's high was either it's from a thermometer placed a few inches in front of the condenser.

                  Yes, 50psi would be over what I normally see in R12 systems on the low side even at 110 degree ambient I doubt I've cracked 40. I had a vintage Mercedes wagon last month that was putting 30 degree air out the vents at 22psi on the low side and 185 on the high on an 85 degree day.


                  I give all old R12 systems a full evac at a station down the road. I draw the system down using my 5cfm pump and charge r12 only from a 30lb cylinder and scale or sealed new cans. I never put reclaimed r12 into the cars and I never mix refrigerants. I assume your higher pressures are due to either atmospheric contamination or refrigerant contamination.

                  Great post......

                  When you mentioned "reclaimed r12" you are referring to products such as Freeze 12 right? Your not referring to fake R12, like a fake Rolex?

                  Do you think its possible I bought what I thought and was stated to me as the real deal R12 and the cans was actually fake Dupont R12 cans with fake R12 in the cans? Thats not possible is it?

                  The mechanic I took the car to says that my remanufactured compressor is a defect. Do you believe that could be the case (I am asking as it seems your very knowledgeable).

                  Comment


                    #10
                    O wait Im thinking 146a numbers. My bad.
                    Ma che cazzo state dicendo? :|

                    Comment


                      #11
                      Originally posted by IS300E30 View Post
                      Great post......
                      When you mentioned "reclaimed r12" you are referring to products such as Freeze 12 right? Your not referring to fake R12, like a fake Rolex?
                      Reclaimed r12 is r12 that has been pulled out of vehicles, some shops have refrigerant "recycling" A/C service equipment, and can pull refrigerant out of vehicles into a 30lb cylinder and then put it back in later. Problem being that I have seen people convert cars such as e30s and then remove the adaptors(some cheap brands of adaptors interfere with the hood operation) or charge the cars with freeze 12, propane, r142b, hc-12a, duracool 12a, ect. without labeling them. All it takes is an older machine that can't identify the refrigerant automatically and a single customer with an illegally converted car and the entire 30lb cylinder of "r12" is contaminated. Some shops may continue charging systems with it but it isn't what you want in your system.



                      Originally posted by IS300E30 View Post
                      Do you think its possible I bought what I thought and was stated to me as the real deal R12 and the cans was actually fake Dupont R12 cans with fake R12 in the cans? Thats not possible is it?
                      When r12 shot from $3.50 a can to $35.00 a can I would say there is certainly room for counterfeiting. I have heard over on the professional mechanics forums last year that some techs were seeing cans of an unknown refrigerant blend coming out of Mexico via ebay but clearly labeled r12. I haven't ever seen a can myself but I believe it because I do know the techs involved personally. If you don't have a 609 license and you bought "r12" online then you were buying it legally so what could you do about it? (ever try and call the cops and tell them your dealer sold you some bad shit ) If you are licensed and walked in to the local auto parts store and purchased it then I doubt it's fake.

                      Originally posted by IS300E30 View Post
                      The mechanic I took the car to says that my remanufactured compressor is a defect. Do you believe that could be the case (I am asking as it seems your very knowledgeable).
                      The compressor could be bad but I can't diagnose it for you over the internet with the information given thus far.

                      Comment


                        #12
                        bimmerteck, you really know your stuff. So, I will continue to ask you questions if you dont mind.

                        The reading for the high pressure was between 225-250 the mechanic stated, he said that was normal....Is it?

                        Also, I did buy the R12 online through Ebay...But, the seller has 100% feedback and he sells a good amount of R12. I hope i got the real stuff. Hopefully its not counterfeit Dupont R12.

                        Also, if the high side is within range (if it is, I will wait for your response) and the low side is too high (53 like I stated). What will I notice when it comes to cooling of the AC?

                        Also, there is no way for you to diagnose if the compressor is bad at all through online conversation is there?

                        Comment


                          #13
                          Originally posted by IS300E30 View Post
                          bimmerteck, you really know your stuff. So, I will continue to ask you questions if you dont mind.
                          Not a problem, it will give me a thread to refer others to when they ask the same questions next summer. :)

                          Originally posted by IS300E30 View Post
                          The reading for the high pressure was between 225-250 the mechanic stated, he said that was normal....Is it?
                          It is normal that the high side should be higher, but how much higher depends on ambient, charge level, refrigerant used, condition of the condenser, ect.


                          Originally posted by IS300E30 View Post
                          Also, I did buy the R12 online through Ebay...But, the seller has 100% feedback and he sells a good amount of R12. I hope i got the real stuff. Hopefully its not counterfeit Dupont R12.
                          PM me the seller info and a pic of the cans if you still have them. If they don't have lot/control#s printed on the cans it's likely that they are either counterfeit or grey market refrigerant. Ebay feedback is irrelevant, people who pay $10 for fake rolexes walk away happy too, but they know what they are buying. Since you've likely never held a genuine can of r12 how would you know what a counterfeit one would look like?


                          Originally posted by IS300E30 View Post
                          Also, if the high side is within range (if it is, I will wait for your response) and the low side is too high (53 like I stated). What will I notice when it comes to cooling of the AC?
                          The system will loose efficiency and the vent temps will usually rise.


                          Originally posted by IS300E30 View Post
                          Also, there is no way for you to diagnose if the compressor is bad at all through online conversation is there?
                          I could make a guess, but I wouldn't replace any hard parts until I verified the refrigerant was not contaminated.



                          Here is an excerpt I found on a website posted in a thread about the "ebay" refrigerant issues.

                          BOOTLEG REFRIGERANT

                          Less dangerous but equally illegal is bootleg R-12 that is being smuggled into the U.S. from offshore. Though most of the industrialized nations have stopped manufacturing R-12 (production ended in the U.S. December 31, 1995), R-12 is still being made in some Third World countries including Mexico. Some of this product is finding its way past customs in mislabeled containers or concealed in various ways. The EPA warns that much of the refrigerant it has confiscated thus far is of poor quality, contaminated by air, moisture, R-22 and other substances. The EPA has worked with customs authorities and the FBI to make a number of arrests. Fines for violating the clean air rules can run up to $25,000 per instance.

                          Counterfeiting branded product is another scam that is being perpetrated to turn a fast buck in today's market. Cylinders of counterfeit Allied Signal Genetron R-12 have reportedly been turning up in various parts of the country. The cylinders do not contain R-12 but some "unknown" refrigerant. Allied Signal says the counterfeit boxes do not have cut-outs where lot numbers strapped on cylinders would appear and there are no bar codes or white painted stripes on the sides. The number "Q 1167" may also appear on the bottom of the packaging. The cylinders themselves may be marked with a pressure-sensitive decal whereas the genuine product has markings printed on the cylinder itself.


                          Source article-
                          http://www.aa1car.com/library/tr497.htm

                          Comment


                            #14
                            PM sent with Ebay info. Thank you :)

                            Also, when you stated

                            "The system will loose efficiency and the vent temps will usually rise."

                            Were you referring to idle, driving or both?

                            Comment


                              #15
                              One of these things is not like the others. . . ;)





                              Counterfeit 14oz cans pictured on top of a genuine box.




                              Genuine cans(from what we can see) 12 oz, brand name spelled correctly, lot numbers visible on 2 of 3 cans.





                              My advice to anyone wanting to keep an r12 system functioning with r12 is to find a 609 certified technician, allow them to source the r12 for you legally and charge the vehicle. Genuine r12 was selling within $10 a can of the questionable stuff being sold on ebay, just now. Saving $30 charging your car isn't worth a possible $25,000 fine and jailtime should the EPA catch you installing it and push the issue.

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