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Car Forum / Dodge / Dodge Trucks / September 2005A/C question
A mechanic says he thinks I have a leak in my evaporator. When I attach a gague to the low pressure valve, it reads over 100 psi (way overfull) Is this guy a dope, or is there something I am missing. >A mechanic says he thinks I have a leak in my evaporator. When I attach a > gague to the low pressure valve, it reads over 100 psi (way overfull) Is > this guy a dope, or is there something I am missing. the compressor should be running when you check the pressures.  SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com Thanks. I will try tomorrow. Shouldn't it read 0 if I have a leak? Also, I am pretty adept at working on cars, but I am a supreme novice when it comes to A/C. Can somebody suggest a good book that I can read to get mor edjucated? Thanks > I am a supreme novice when > it comes to A/C. Can somebody suggest a good book that I can read to get > mor edjucated? take your vehicle to a qualified service technician. a/c isnt something for the novice. you can bullshit your way through it with the $9 pressure gauge from pep boys, but you need to fix the leak before you bother with charging the system (unless youre just looking for a temporary fix). SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com The thing is, I would really like to learn, and what a golden opportunity now that I have a broken system (I actually have two) to get some experience. I am not afraid to spend some money on equipment, I just don't know what to buy, or how to use it. If what you are saying is that it is too complicated, or involved for the do-it-yourselfer I respect that I guess. Does anybody know a way that a guy like me could learn more? The problem with AC is that you are dealing with high pressures and if you screw up, things can go wrong that can hurt you as well as damage expensive components like the compressor. Another problem is that many of the tools used for AC service and repair are pretty much useless for much else and are rather expensive. I myself look at the cost and usability of the tools and my time compared to the cost of having the repair done. If I have other uses for the tools or I know that I will need to use them again then I buy them and make the repair myself otherwise it makes more economic sense to just have the repair done for me. There are books on this stuff and if you really want to learn, I would go there first. SignatureIf at first you don't succeed, you're not cut out for skydiving > The thing is, I would really like to learn, and what a golden opportunity > now that I have a broken system (I actually have two) to get some [quoted text clipped - 7 lines] > > Does anybody know a way that a guy like me could learn more? So what tools are so expensive that are required to work on an A/C system? I have been working on them for years and can't think of any tool that is that expensive. With a set of gauges and a book telling you what pressure at what temp you should be looking for I can't think of anything on an auto that is much easier to do than charge an A/C system. Yes maybe a vacuum pump but if you are a little resourceful a used compressor out of an old refrigerator with a connector on it makes a great vacuum pump and basically free. > The problem with AC is that you are dealing with high pressures and if you > screw up, things can go wrong that can hurt you as well as damage expensive [quoted text clipped - 6 lines] > just have the repair done for me. There are books on this stuff and if you > really want to learn, I would go there first. > So what tools are so expensive that are required to work on an A/C system? vacuum pump ($300). recovery unit ($800). recovery tank ($100), proper gauges ($100-$300). all sorts of hand tools. > a used compressor out of an old refrigerator with a connector on it makes > a great vacuum pump and basically free. i find this statement ignorant, foolish, and very irresponsible. you can _not_ pull adequate vacuum with a used compressor. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com > > a used compressor out of an old refrigerator with a connector on it makes > > a great vacuum pump and basically free. > > i find this statement ignorant, foolish, and very irresponsible. you can > _not_ pull adequate vacuum with a used compressor. no, but it IS handy for pumping the system down to see if it holds vacuum if it holds, THEN hook up the 'big dog' overnight and, BTW........if you find an OLD one (pre about 1980), you'd be surprised how good a vacuum it WILL produce the new ones are for crap for this use, tho > no, but it IS handy for pumping the system down to see if it holds vacuum > > if it holds, THEN hook up the 'big dog' overnight so why go through the trouble to begin with? if you have the "big dog" (and youll HAVE to at some point before charging the system), why bother with a makeshift system just to see if it will hold the vacuum? besides, with proper equipment (a 2 stage vacuum pump) its pointless to bother with an overnight pull. a quality vacuum pump will pull it down just as hard in 15 minutes as it will in 24 hours. > and, BTW........if you find an OLD one (pre about 1980), you'd be > surprised > how good a vacuum it WILL produce it may produce more vacuum than the newer compressors, but it will _never_ produce anywhere near the 500 micron target which is required to pull out all the moisture and non-condensables. there are a _lot_ of home remedies that might get you by, but this is what makes the difference in 45 degree vent temps and 55 degree vent temps. having the proper tools makes the difference in a 3 year expected service life, and a 15 year service life. if its 101 degrees out and you dont have any money i guess you do what you gotta do to get by. hell, i ran propane in my camaro a/c system when i was 17 lol. but in hvac/r there is no short-cut, and no way to save any money if you want to consider it fixed right. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com > > no, but it IS handy for pumping the system down to see if it holds vacuum > > [quoted text clipped - 3 lines] > youll HAVE to at some point before charging the system), why bother with a > makeshift system just to see if it will hold the vacuum? because in central IL in August, you may have 2 or even three jobs going at once.............. I can 'test' one while I pump the other and charge a third >besides, with > proper equipment (a 2 stage vacuum pump) its pointless to bother with an [quoted text clipped - 16 lines] > 17 lol. but in hvac/r there is no short-cut, and no way to save any money > if you want to consider it fixed right. I never said there was, and I fix it right >>no, but it IS handy for pumping the system down to see if it holds vacuum >> [quoted text clipped - 6 lines] > overnight pull. a quality vacuum pump will pull it down just as hard in 15 > minutes as it will in 24 hours. So how HARD is HARD (atmospheres) ? >>and, BTW........if you find an OLD one (pre about 1980), you'd be >>surprised [quoted text clipped - 6 lines] > vent temps and 55 degree vent temps. having the proper tools makes the > difference in a 3 year expected service life, and a 15 year service life. I think you have better find one and try it before you say that pulling that little bit of extra vacuum will product a colder vent temp. So how many atmospheres does one of these super vacuum pumps pull ? > if its 101 degrees out and you dont have any money i guess you do what you > gotta do to get by. hell, i ran propane in my camaro a/c system when i was > 17 lol. but in hvac/r there is no short-cut, and no way to save any money > if you want to consider it fixed right. I have found that when a HVAC system has really failed it should just simply be replaced with a completely new system. It ends up being the overall cheapest way to do. Usually the new system is so far more efficient that it will pay for itself in a couple of years. > So how HARD is HARD (atmospheres) ? as previously stated, you need to pull a vacuum to at least 500 microns in order to properly evacuate the system of moisture and non-condensables. > I think you have better find one and try it before you say that done it _many_ times with any type of compressor you can name. having used a micron gauge on it i can tell you with authority that youll never achieve 25% of your target 500 microns. > I have found that when a HVAC system has really failed it should just > simply be replaced with a completely new system. it depends upon what you mean by "really failed". a minor leak is nothing. most of the charging products contain leak stopper and ive found it very effective in the past (if its a seal issue). SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com With any AC car, home or commercial when it's opened to the atmosphere you need to evacuate the system. Meaning you need to remove ALL of the air and moisture from the system. I have no clue what the cost of the equipment for evacuating and measuring a charge is for a vehicle but you're going to spend a grand or more for the equipment for similar residential equipment. That's assuming you have nothing to recover. >The thing is, I would really like to learn, and what a golden opportunity >now that I have a broken system (I actually have two) to get some [quoted text clipped - 7 lines] > >Does anybody know a way that a guy like me could learn more? A $1,000 you got to be kidding. Be resourceful and it will not even cost $100. Yes if you are going ot follow the law then buy the recovery system but I find that most A/C is discharged anyway when it needs work and if you have to discharge a little of what is left then just close your eyes and do it. Also remember every auto A/C system is set up to leak and will. If you have to add a can every other year or even every year that does not mean you have to get it fixed or may not even be able to fix any better that that. Any place that you have a shaft with a seal around it will leak. Now that brings up a question, Why didn't the auto industry go with a sealed compressor and operate it off a a generator that generator a higher voltage than 12 volts to keep the current down. Now that would have been more of a environment fix that saying no more R-12. > With any AC car, home or commercial when it's opened to the atmosphere > you need to evacuate the system. Meaning you need to remove ALL of [quoted text clipped - 15 lines] >> >>Does anybody know a way that a guy like me could learn more? >A $1,000 you got to be kidding. Be resourceful and it will not even cost >$100. Yes if you are going ot follow the law then buy the recovery system >but I find that most A/C is discharged anyway when it needs work and if you >have to discharge a little of what is left then just close your eyes and do >it. Been doing this for years. My recovery system is a tub of ice and a Freon cylinder. Yes, it's slow. Yes, it does not remove every bit of Freon. But it does get all the liquid so you're not releasing much. As far as a vacuum pump. I use an old refrigerator compressor. They way you get the moisture out is you pull a vacuum. Wait to see if it leaks. Might have to do this a few times as Freon hides in the oil and takes a while to come out. Then you add a bit of Nitrogen, about 3 PSI. Wait a while and pull vacuum again. The Nitrogen will get the moisture out. While you're pulling vacuum the last time heat the receiver/dryer with a hair dryer. Before you ask, we have race cars that we use Nitrogen to control the throttle so we always have it. But, it's not hard to get and if the system has not been exposed to air a long time you can skip using it. Al > As far as a vacuum pump. I use an old refrigerator compressor. you will NEVER under the best of circumstances achieve anywhere near (not even close) to the 500 micron target with a refrigerator compressor. you might think it works great for you and thats fine and well but dont mislead others into thinking your way works because it doesnt. it might enable you to get cool air from your vents but its not as cool as it would be if it were done right.....and your components wont last as long as they should. you arent pulling a deep enough vacuum to evacuate all moisture and non-condensables. sure it might get you by and im not busting your chops on this. i just dont want others to think this is an accepable alternative. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com Hey Nate, where do you get your vacuum pump oil? SignatureIf at first you don't succeed, you're not cut out for skydiving > > As far as a vacuum pump. I use an old refrigerator compressor. > [quoted text clipped - 7 lines] > non-condensables. sure it might get you by and im not busting your chops on > this. i just dont want others to think this is an accepable alternative. > Hey Nate, where do you get your vacuum pump oil? i buy it in bulk at johnstones here in billings. i buy in bulk because i change the oil in my vacuum pump after _every_ usage as recommended by my vacuum pump manufacturer. this is why i attach a $5 vacuum pump charge each time i use it (although most companies charge 15). why? SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com Because the fluid in my pump is getting old and is about due for a change. Do you know of any retail places here in NC in the Raleigh area. SignatureIf at first you don't succeed, you're not cut out for skydiving > > Hey Nate, where do you get your vacuum pump oil? > [quoted text clipped - 4 lines] > > why? > Because the fluid in my pump is getting old and is about due for a change. you dont change it after each use, or its just been sitting or what? > Do you know of any retail places here in NC in the Raleigh area. i would recommend johnstones, although they may require you have an account with them. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com > > Because the fluid in my pump is getting old and is about due for a change. > > you dont change it after each use, or its just been sitting or what? This is an industrial vacuum pump and nowhere does it say to change the oil after each use. Probably because it was not built for the sole purpose of air conditioning service. Actually, it used to live at Bendix with about 5 of its brothers running 24/7 to test flight control systems. > > Do you know of any retail places here in NC in the Raleigh area. > > i would recommend johnstones, although they may require you have an account > with them. Ok, I will check that out. SignatureIf at first you don't succeed, you're not cut out for skydiving >> i would recommend johnstones, although they may require you have an > account >> with them. > > Ok, I will check that out. if they tell you that you need an account, use mine. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com On 8/17/05 6:34 PM, in article 11g7lt28tbpmj96@corp.supernews.com, "Nathan W. Collier" <MontanaJeeper@aol.com> wrote: >>> i would recommend johnstones, although they may require you have an >> account [quoted text clipped - 3 lines] > > if they tell you that you need an account, use mine. You mean your bank account :))), I could use some Dale I just did a compressor change out on an 1989 F-250. I used a commercial vacuum pump that pulled a vacuum of around 27. What I want to comment on is that my FORD service manual states pull a vacuum of at least 25 for a max of 30 minutes if the whole system had been replaced. Now 25 is not that great of vacuum and far less than someone on this group has been saying is required. So far I did everything that the FORD manual stated and everything seems to be working OK. What I also found interesting is that the FORD manual said after you disconnect the vacuum pump make sure that the system will hold that vacuum for at least 5 minutes. Now I do have a problem with this statement. I would probably be bringing the new compressor back for a refund it is only held a vacuum for 5 minutes. Ron >>>Because the fluid in my pump is getting old and is about due for a > [quoted text clipped - 16 lines] > > Ok, I will check that out. > Now 25 is not that great of vacuum and far less than someone on this > group has been saying is required. you pulled 25Hg. thats not the same thing as 500 microns. > I would probably be bringing the new compressor back for a refund it is > only held a vacuum for 5 minutes. youre reading it wrong. it means to wait at least 5 minutes to make sure it holds the vacuum. if it will hold vacuum for 5 minutes it will hold vacuum indefinately. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com It states (the FORD service manual) at least 25 inches of Mercury and as close to 30 that you came get. You are right that is not the same as 500 microns. So how does microns relate to inches of mercury ? So what is so magical about 5 minutes why not 2 minutes or 10 minutes or 24 hours ? I help a vacuum over night on the last job with no problem but the compressor seals would not work in reverse so the vacuum test was basically worthless as far as telling me the seals were good ? >> Now 25 is not that great of vacuum and far less than someone on this >>group has been saying is required. [quoted text clipped - 7 lines] > holds the vacuum. if it will hold vacuum for 5 minutes it will hold vacuum > indefinately. Pulling a vacuum helps in the determination of whether a system is leaking or not. More importantly you do it to remove non-condensibles from the system. >It states (the FORD service manual) at least 25 inches of Mercury and as >close to 30 that you came get. You are right that is not the same as 500 [quoted text clipped - 16 lines] >> holds the vacuum. if it will hold vacuum for 5 minutes it will hold vacuum >> indefinately. Micron is really almost a useless measurement to almost anyone that is reading this newsgroup. It cannot be measured with the equipment available to the service or home repair person. Vacuum pumps are specified in volume/sec and inches of mercury. Volume is not important to us because we are working in a closed system if we had a hole in one end and were trying to keep a vacuum inside then volume per minutes would be very important now I sure hope everyone knows that you must have your AC system closed before you start drawing your vacuum. So now all we need to do is determine what the min vacuum we need to pull and from what I understand now about this subject almost anything that will draw a vacuum will work just fine on our AC systems if it can acheive a certain ?? inches of Mercury. So now lets get off this micron issue and on to something that we all can measure. If a manufacture of a specific vacuum pump states it can draw 50 micron then at what inches of mercury are they talking because then any vacuum pump that can achieve that pull will do that same thing, volume again is not important. Thank you, Ron in Phx, AZ where AC is required. > It states (the FORD service manual) at least 25 inches of Mercury and as > close to 30 that you came get. You are right that is not the same as 500 [quoted text clipped - 16 lines] >> sure it holds the vacuum. if it will hold vacuum for 5 minutes it >> will hold vacuum indefinately. > Micron is really almost a useless measurement to almost anyone that is > reading this newsgroup. .....if you dont care about doing the job properly that is. > It cannot be measured with the equipment available to the service or home > repair person. ?? i paid less for my micron gauge than i paid for my pressure gauges. > from what I understand now about this subject almost anything that will > draw a vacuum will work just fine on our AC systems if it can acheive a > certain ?? inches of Mercury. if it can pull 500 microns it will work just fine in your a/c systems. if it wont (and it wont) its _not_ "ok" to use it. sure it will make the system run and cool but it will NOT cool as efficiently as it would if it were done right. the suggestion that it will is irresponsible at best. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com So now lets get off this micron issue and > on to something that we all can measure. If a manufacture of a specific > vacuum pump states it can draw 50 micron then at what inches of mercury [quoted text clipped - 24 lines] >>> sure it holds the vacuum. if it will hold vacuum for 5 minutes it will >>> hold vacuum indefinately. >Micron is really almost a useless measurement to almost anyone that is >reading this newsgroup. It cannot be measured with the equipment >available to the service or home repair person. Vacuum pumps are No, any self respecting residential service tech has a micron gauge. I don't have a clue how often they're used in automotive AC but I suspect not often. >specified in volume/sec and inches of mercury. Volume is not important >to us because we are working in a closed system if we had a hole in one [quoted text clipped - 9 lines] >are they talking because then any vacuum pump that can achieve that pull >will do that same thing, volume again is not important. A micron is 0.001mm. There are about 25400 microns to an inch. A gauge set simply doesn't have the resolution to measure a 500 micron vacuum. BTW, a perfect vacuum would be 0 microns. 500 microns is 0.5mm. > microns. So how does microns relate to inches of mercury ? Micrometers... 1 millionth of an inch. 1" of Hg = 25,400 microns of Hg. However, the scale is inverted. In other words, a perfect vacuum (29.921" of Hg at sea level) is 0 microns. Therefore, 500 microns is about 29.903" of Hg. > So how does microns relate to inches of mercury ? microns are smaller incriments of measure and are much more "sensitive" and accurate than Hg. > So what is so magical about 5 minutes why not 2 minutes or 10 minutes or > 24 hours ? its just a guestimate. i typically do something else for 15 minutes and check back. > the compressor seals would not work in reverse so the vacuum test was > basically worthless as far as telling me the seals were good ? if thats the case you should charge the system with nitrogen and make sure it maintains pressure. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com will someone please answer the question that was asked a couple posts ago: what does '500 microns' equal in inches of mercury ? > > So how does microns relate to inches of mercury ? > [quoted text clipped - 12 lines] > if thats the case you should charge the system with nitrogen and make sure > it maintains pressure. > will someone please answer the question that was asked a couple posts ago: > > what does '500 microns' equal in inches of mercury ? I thought I did... 29.903" >> will someone please answer the question that was asked a couple posts >> ago: >> >> what does '500 microns' equal in inches of mercury ? > > I thought I did... 29.903" You did, he wasn't paying attention in class. Gary, go stand in the corner.<G> Roy >>will someone please answer the question that was asked a couple posts ago: >> >>what does '500 microns' equal in inches of mercury ? > > I thought I did... 29.903" OK got that one answered now I would like to see a temperature chart of the center register discharge temperature versus vacuum drawn on your typical fixed orifice tube auto AC system. From No vacuum pulled in five degree steps to 29.903 which is almost a perfect vacuum. I personally believe that what you will see is a straight line or two straight lines with anything between these two temps being OK and that vacuum is not related to the temperature output on your typical auto AC at all. The size and condition of the system, the fixed orifice tube and the amount of oil in the system will set the output temp. Please prove me wrong on this because if a super vacuum will get my AC 20 degrees cooler here in Phx, AZ I am for it. I did see yesterday that there is a new fixed orifice tube that is really not fixed but variable that is claiming 12 degree better cooling at idle of course I found this after I filled the system with a new charge. If I had a recovery tank I would be installing one of these. The purpose of drawing a vacuum is to get the moisture out of a system that will cause corrosion and I real believe that is all. Right or Wrong ? I need hard facts or a website that explains this in detail if a vacuum will really drastically improve cooling. Thanks Ron > vacuum is not related to the temperature output on your typical auto AC at > all. if you have moisure or non-condensables in your system it cannot possibly work as efficiently as it would if it were pulled down into a proper vacuum. > Please prove me wrong on this because if a super vacuum will get my AC 20 > degrees cooler here in Phx, AZ I am for it. nobody said 20 degrees. if you pull a vacuum with a pressure gauge and a refrigerator compressor you might see a difference of 8-10 degrees. if you use a better vacuum source the difference may only be 1-2 degrees...but there will be a difference. we within the industry dont spend $300 for a decent 2 stage vacuum pump for the hell of it. we do it because as professionals we want to give you the best service possible and that means doing it right. if the cheaper alternatives were "ok" we would certainly use them (i got dozens of compressors of all types and size that it ok off jobsites in equipment being replaced) and same some money. > The purpose of drawing a vacuum is to get the moisture out of a system > that will cause corrosion and I real believe that is all. Right or Wrong > ? and non-condensables which hinder cooling and can be fatal to compressors and metering devices. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com Now that sounds a lot better 1 to 2 degrees is not worth my money as a home repair do it yourself person unless I can find a good suction pump used really cheap. When it 120 ambient and the inside of the car is in the 160 degree range 1 to 2 degrees will not be detected. 10 to 12 maybe but questionable. I have no problem with a professional using the best possible tools if they understand them and aren't just using them for show. I am afraid most do not understand them though and might not even use them most of the time. I turned my AC on this morning. I installed a new compressor yesterday. The air was so much colder I turned the fan down to low and all of a sudden got smoke that smelled like wood burning coming out of the vents. I thought about it for a while then determined there must be something in the resistors that control the fan that got burned. Sure enough it was packed with leaves. I did get a good look at the evaporator and could see that it was really packed with stuff also so off with the sides to see if I could wash it out. Got the garden hose with a high pressure nosel on it and now it looks like it will pass some air. I have no doubt that it was almost 50 per cent restricted. Just about ready to reassemble and see now much better it will be. So how do all these other non-condensables get into a closed system ? Moisture I understand and metal parts for things breaking but if the system came from the factory with a good charge and then a seal started to leak I would not expect to have anymore non-condensables in the system after I replace the compressor than before I replaced it other than mybe some moisture from having the system opened. Back to work (I guess a retired person shouldn't use the word work so back to my fun project) Ron >>vacuum is not related to the temperature output on your typical auto AC at >>all. [quoted text clipped - 21 lines] > and non-condensables which hinder cooling and can be fatal to compressors > and metering devices. > Now that sounds a lot better 1 to 2 degrees is not worth my money as a > home repair do it yourself person unless I can find a good suction pump > used really cheap. bear in mind that its also an issue of compressor/metering device damage. it may only shorten component life by a little, but it will shorten component life. > So how do all these other non-condensables get into a closed system ? its no longer a closed system once you open it to replace the compressor or other components. you also have component disentigration, minute particles left from machining the new components, etc. where you have moving parts, you have wear. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com New question ? How long is the meant time before failure of your typical auto AC system and what is the normal failure ? I have 4 vehicles with AC systems that have a combined mileage of around 750,000 miles. I have replaced three compressors. One was an old York piston unit on a 1969 auto that broke a rod at about 200,000 miles. The other two where new style compessors and both were replaced because of seal leaks. The fourth unit is an original York piston unit that is still working great and is 36 years old. I seem to have more problem with seals going bad than compressor blowing apart so I would have to say seal failure is the big failure mode. How off normal am I ? I also never buy spark plugs and find very few bad spark plug wires. I laughed the other day when I was in an AutoZone store and saw a complete wall full of spark plug wires and all I could think about was all the good wires that were being thrown away. > New question ? > > How long is the meant time before failure of your typical auto AC system > and what is the normal failure ? i really dont think there is a realistic way to answer that question. you _should_ be able to expect 10 years of trouble free operation, but ive seen many go much longer, and many only last a couple years. id guess the most common failure is seal failure. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com >New question ? > [quoted text clipped - 13 lines] >still working great and is 36 years old. I seem to have more problem >with seals going bad than compressor blowing apart so I would have to >say seal failure is the big failure mode. How off normal am I ? I >also >never buy spark plugs and find very few bad spark plug wires. I >laughed >the other day when I was in an AutoZone store and saw a complete wall >full of spark plug wires and all I could think about was all the good >wires that were being thrown away. It depends on the usage of the unit and the climate you live in too. If you live in Teaxs and use it a lot, it will not last as long but I have gotten 200k out of a few compressors and my 89 burb had its compressor replaced at 45k under extended warranty because of quality problems with compressors that year but its replacement is still doing fine 130k miles later. > will someone please answer the question that was asked a couple posts ago: > > what does '500 microns' equal in inches of mercury ? tom already did, last night. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com Now don't confuse Gary with the facts :-) SignatureIf at first you don't succeed, you're not cut out for skydiving > > will someone please answer the question that was asked a couple posts ago: > > > > what does '500 microns' equal in inches of mercury ? > > tom already did, last night. "TBone" are you in michigan? Local bendix plant unloaded a bunch of vac. pumps about 5 years ago. > This is an industrial vacuum pump and nowhere does it say to change the > oil [quoted text clipped - 10 lines] > > Ok, I will check that out. Nope, from NJ and now in NC. My vacuum pump came from Bendix aerospace in NJ many years ago. My dad worked there and picked it up when they moved the division that used them to PA. SignatureIf at first you don't succeed, you're not cut out for skydiving > > "TBone" are you in michigan? Local bendix plant unloaded a bunch of vac. [quoted text clipped - 14 lines] > > > > Ok, I will check that out. It sure sounds like it works for a few of use and I personally have never had a problem and have always had cold air when it hits 120 F outside. ollier wrote: >>As far as a vacuum pump. I use an old refrigerator compressor. > [quoted text clipped - 7 lines] > non-condensables. sure it might get you by and im not busting your chops on > this. i just dont want others to think this is an accepable alternative. Yup works for me also and doesn't cost anyway near big bucks. >>A $1,000 you got to be kidding. Be resourceful and it will not even cost >>$100. Yes if you are going ot follow the law then buy the recovery system [quoted text clipped - 16 lines] > > Al check your local technical colledge. the ones around here will offer "certificate" classes in automotive repair. and yes they do offer one in auto hvac. > The thing is, I would really like to learn, and what a golden opportunity > now that I have a broken system (I actually have two) to get some [quoted text clipped - 7 lines] > > Does anybody know a way that a guy like me could learn more? i should add. i highly stress the importance of being properly educated in hvac repair. the dangers of dealing with the refigerant are hidden and apparent both. please take a class for your own information. in the mean time. take it to a shop and have a certified professional work on it. it'll be safer for you and the vehicle both. > check your local technical colledge. the ones around here will offer > "certificate" classes in automotive repair. and yes they do offer one in [quoted text clipped - 11 lines] > > > > Does anybody know a way that a guy like me could learn more? The thing is, I would really like to learn, and what a golden opportunity now that I have a broken system (I actually have two) to get some experience. I am not afraid to spend some money on equipment, I just don't know what to buy, or how to use it. If what you are saying is that it is too complicated, or involved for the do-it-yourselfer I respect that I guess. Does anybody know a way that a guy like me could learn more? > If what you are saying is that it is too complicated, or involved for the > do-it-yourselfer I respect that I guess. if youre _serious_ about learning more (for possibly a career?) i recommend strongly that you begin to consider a tech course. refrigeration/hvac is what i do for a living (http://BighornRefrigeration.com) and its been very good to me (in addition to welding). i cannot stress enough the importance of learning right before you pick up any bad habits. i was initially self-taught and although i could get by, for the most part i was a bumbling idiot until i got some formal training. if its what you want to do youll make a lot of money doing it.....just learn to do it right by getting formal instruction. if you just want the basics, go to the library. haynes also makes a tech manual for a/c thats very basic. drop by your local auto parts store and pick up a copy. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com >> If what you are saying is that it is too complicated, or involved for the >> do-it-yourselfer I respect that I guess. [quoted text clipped - 7 lines] > although i could get by, for the most part i was a bumbling idiot until i > got some formal training. So now you are no longer bumbling? <GBFG> It was just laying there, so I just had to. Roy >>>If what you are saying is that it is too complicated, or involved for the >>>do-it-yourselfer I respect that I guess. [quoted text clipped - 12 lines] > > Roy Yup I believe he is still the idiot though. I know more self taught people that know far more than formally taught person. It has to do with getting the books and reading them and also a person's ability to understand also with common sense which most people do not have. >>>>If what you are saying is that it is too complicated, or involved for >>>>the [quoted text clipped - 14 lines] >> Roy > Yup I believe he is still the idiot though. Not hardly. That was in jest, guess you didn't see the gbfg > I know more self taught people that know far more than formally taught > person. It has to do with getting the books and reading them and also a > person's ability to understand also with common sense which most people do > not have. Hmmm.. wonder where you live that all these self taught folks have all this expertise. Also wonder on who's equipment they screwed until they got it right. Thanks. I will try tomorrow. Shouldn't it read 0 if I have a leak? Also, I am pretty adept at working on cars, but I am a supreme novice when it comes to A/C. Can somebody suggest a good book that I can read to get mor edjucated? Thanks > A mechanic says he thinks I have a leak in my evaporator. When I attach a > gague to the low pressure valve, it reads over 100 psi (way overfull) Is > this guy a dope, or is there something I am missing. Lots of great information at this site: http://www.autoacforum.com/ I learned how to do mine this summer after reading the above forum. Good luck. Bob if you have 100 psi, running or not, you probably don't have a leak what's the pressures with it running ? and why does this 'mechanic' 'think' that you 'have a leak' ? low funds ? > A mechanic says he thinks I have a leak in my evaporator. When I attach a > gague to the low pressure valve, it reads over 100 psi (way overfull) Is > this guy a dope, or is there something I am missing. Thank you all very much for the comments!!! You have all been very helpful to me. I think TranSurgeon sees what I'm afraid of with the low funds comment. According to the mechanic, I have a leak and it must be in the evaporator, because he looked everywhere else. It could be true. It is just a very expensive repair and I would like to feel very secure that I am replacing the right part. I appreciate the section where people debated about the cost of the tools. I just measured the low side pressure with the AC system running and it was doing the following: The compressor would click on and the reading would drop down to about 20, then it would click off and the pressure would rise back up to about 45. The compressor is clicking on and off every five seconds or so. Is this how the guy "knows" I have a leak? Again, I really appreciate the help in learning about this. it MIGHT just be low,...............BUT: without a 'sniffer' leak detector, you are shooting in the dark take it to a different shop that does AC, and ask them to 'sniff' at the condensate drain tube that will answer your question very quickly G > Thank you all very much for the comments!!! > [quoted text clipped - 19 lines] > > Again, I really appreciate the help in learning about this. I will try to find somebody with this "sniffer" type detector, and tell them what you said. If they say that they found a leak for sure, I would feel much better about them getting in there and changing out the evaporator. If they don't find a leak, what other possible problems might cause a system to act this way? I will try to find somebody with this "sniffer" type detector, and tell them what you said. If they say that they found a leak for sure, I would feel much better about them getting in there and changing out the evaporator. If they don't find a leak, what other possible problems might cause a system to act this way? > If they don't find a leak, what other possible problems might cause a > system to act this way? if the compressor is cycling on and off, chances are the system is low on refrigerant. honestly i probably wouldnt bother with getting the leak fixed just yet. wal mart sells the quick charge 134a systems for about $8. they also sell a color coded gauge for $9 that will tell you when youre properly charged (points at green). pick up 1 of each, run your system, and add 1 can then check it with your gauge. if its a small leak, that $8 charge might get you by for a couple years. if the leak is very small i wouldnt bother with the expense of fixing it. throw $8 in it every couple years and dont think about it anymore. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com slow leak around the compressor shaft rock chip nicked the condenser any and all connections should be suspect, especially if you see an oily film around them > I will try to find somebody with this "sniffer" type detector, and tell > them what you said. If they say that they found a leak for sure, I would [quoted text clipped - 3 lines] > If they don't find a leak, what other possible problems might cause a > system to act this way? ALRIGHT!!! For now... I am finally cool! Can I really expect this bliss to last? (Probably not) I added about half a can and the A/C works great. I guess if I have a leak, it will stop working. I also guess that if the leak is slow enough I will have saved myself about 1500 bucks thanks to you guys and your patience. > if the leak is slow enough I will have saved myself > about 1500 bucks thanks to you guys and your patience. let me know where to send the bill. :-) SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com I think you got it that is if it will hold for a least 9 months. Just remember all compressors will leak some so having to add a little every so often is not a problem. > ALRIGHT!!! > [quoted text clipped - 7 lines] > I also guess that if the leak is slow enough I will have saved myself > about 1500 bucks thanks to you guys and your patience. The compressor should be clicking on and off at a rate determined by the ambient temperature. Whats the high side pressure ? > Thank you all very much for the comments!!! > [quoted text clipped - 19 lines] > > Again, I really appreciate the help in learning about this. > The compressor should be clicking on and off at a rate determined by the > ambient temperature. its clicking on and off on the low pressure switch. SignatureNathan W. Collier http://InlineDiesel.com http://7SlotGrille.com http://UtilityOffRoad.com http://BighornRefrigeration.com >if you have 100 psi, running or not, you probably don’t have a >leak [quoted text clipped - 5 lines] > >low funds ? The amount of pressure you have in system depends on the tempature of the system but this is not a accurate test always because as long as there is enough freon in the system to keep some liquid under pressure the pressure will be at a constant vs tempature. The real "test" of a charge state is when it is running and tempature and humidity is factored in. It is not cut and dried as some would lead you to believe. It is all very simple unless you are a simple minded persons. >>if you have 100 psi, running or not, you probably don’t have a >>leak [quoted text clipped - 13 lines] > humidity is factored in. It is not cut and dried as some would lead > you to believe. |
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