How do you test the A/C system in your shop in December, in Michigan or anywhere else it's winter and cold? Thanks for the great info. Engine torque conditions are within normal parameters. Under vacuum, the seals or O-rings will move in one direction and under pressure they will move in the other direction. Shine the ultraviolet lamp around the suspected areas. Your system may not leak under a vacuum, but under pressure it may. If the surrounding air is contaminated with refrigerant gas, the leak tester will indicate gas all the time. If it had a leak any bigger than what will get past the crank seal naturally over many years, it would have had zero pressure. I used argon from my TIG setup instead. You would be better off pressure testing the system as well as vacuum testing. Let me explain that with an actual example. The initial starting point for this test was the band at 2.4 on the scale. IMPORTANT: DO NOT exceed the recommended pressures (use a pressure regulator) and DO NOT operate the air conditioning system with oxygen free nitrogen (OFN) in the refrigerant circuit. Compare your results to the tables in the service manual (Figure 9). If you continue to use this site we will assume that you are happy with it. The answer? Check for TSBs and other possible pattern failures during this check. Ford introduced the Flex in the late Summer of 2008. Every evaporator unit, electrical part down to vintage auto air conditioning systems in most mid 1960s to mid 1970s GM vehicles and some 1970s Fords include a POA valve. It is often quite cold in those months, yet I never had difficulty in teaching this subject for those techs and students. How could I demonstrate it? Your email address will not be published. Compressor, lines, receiver-dryer or accumulator, heat exchangers. 7. It's based upon my experience as an engineer at one of the OEM manufacturers. These defined readings will tell you, based on the charts, what is the likely concern. We've updated our forums!Click here to visit the new forum, I wanted to test my car's r-134a system for a leak using compressed nitrogen. The EPA also has stiff fines, and penalties for people who illegally work on A/C, and refrigeration systems weather you are a technician or not. I have never seen an AC system pressure tested. A case in point is our in-dash air conditioning and heater We recently heard from a customer interested in having his original 71 Pontiac LeMans evaporator unit with POA valve rebuilt & restored and set up for 134a. Let's get back to how to test the A/C system of that car sitting in your stall regardless of the month and ambient conditions: 1. After 90 seconds the flow has dropped to 1.0 indicating sealant in the system. NOTE: Leak testing dye may have already been added to the system by the vehicle manufacturer. Following the manufacturers instructions add the amount of dye stated to the refrigerant system. The EPA is requesting that techs re-certify for R-1234yf but are not requiring it at this point. Give me a minute to finish the process and I'll explain the differences for cold-weather testing. I was recently talking with a sales rep from one of the large parts house chains, he was explaining that they sold a device that attached to your machine and would strain the sealant out during evacuation, protecting your machine from damage. Evacuation Purpose #2: Removing Air Because there is only so much volume available within an AC system, its essential that air is removed from the system to allow for the refrigerant and oil. (Direct Electric Replacement ) controls, we have received loads of requests Later in the month of April, I'm heading to New York City to see two icons brought together who haven't met in decades. . Be aware the federal regulations do not require that you do leak repair. The signal and intensity will change as the concentration of refrigerant gas increases or decreases. How do you test an A/C system? What does low side mean? Leak testing using oxygen free nitrogen (OFN)Nitrogen has a molecular structure which makes it suitable to find most leaks, and in addition it is reasonably priced. I don't have an A/C machine at home but I do have a set of gauges. This missing cap represents a leak of about one-quarter pound of refrigerant a year. Let me translate that for you to be very clear. I fibbed earlier about using nitrogen. If the air conditioning system is still operational there should be sufficient pressure in the circuit (at least 3.5 bar), to carry out an effective leak test. The original filter/dryers are no longer available. New Filter Drier Note If your evacuation is done as part of a new system install, youll have already installed a new filter drier but if it is part of a system repair, dont forget to replace the old filter drier. During hands-on training, I would create bugged vehicles that the technician or student had to analyze for the likely/correct fault. If the source of the refrigerant leak cannot be found through visual inspection, there are various other methods available. For hard to reach items, like the evaporator, check the condensation drain. It also required a recalibration of the PCM. When he charged an air-filled system, he created pressures that were way too high. Why 30-45 minutes? As a technician who spent his career in Michigan, I can say that we did very little A/C work in December. It is showing that ambient temperature is ~70 degrees and the refrigerant pressure is `70psi. You may use a factory tool like this Ford IDS, or any number of aftermarket tools that can reprogram and test using bi-directional control. If you are not EPA certified 608 and 609 at a minimum you should not attemp to service the system. If your high and low side gauges to not read equal pressure after just a moment; this could be an indication of a solid/hard restriction somewhere in the system. You may be able to check for leaks, but even in Death Valley youre not getting out much moisture. If vacuum loss is less than 2 Hg, Youre ready to charge. Recharged system and it's working fine now. That said, weve run into many experienced car guys who dont really understand evacuation and decided a quick summary would be helpful to even licensed AC professionals. when you turned it over by hand did you have the power on and the clutch was engaged or was it just freewheeling the bearing? The engine is at operating temperature, the AC system has been running for at least 10 minutes. Using an injector, dye can also be added to the low pressure (suction) side when the system is being charged. I've done that on my truck and Concorde. Figure 2 - Examples of tools needed to test the AC system. How could I know the techs/students had learned how to test the system and be confident that the techniques would work when called upon, when evaluating A/C in the winter? On this vehicle there is communication across three networks and between four ECUs, just to turn the compressor on! Independent Automotive Aftermarket Federation, VLS - Verification of Lubrication Specifications, Original Equipment Suppliers Aftermarket Association (OESAA). No, I'm not talking about seeing Rocky meet up with Apollo Can aftermarket air conditioning components improve on OEM design? There are some states and cities that do require leak repair. This also means that your equipment may not be able to connect to the system. Factory original purists may balk, but sometimes original dashboard designs can be improved upon. The Performance Test, FOLLOWING SERVICE MANUAL PROCEDURES, (sorry to yell) is the key to the process. "For consideration" means that you are receiving some form of compensation for doing the work. I looked down at the controls and noticed that the outside air temp was reading was 110 degrees. Dye is one of the best methods to get that done, you can try one of those little electric sniffers..however I've never had any luck with those. 1969 Pontiac GTO Lemans Air Conditioning Upgrade, Six-Steps Hand Charging A Fixed Displacement Compressor with 134a. Commercial installers of our kits as well as professional, licensed air conditioning repair facilities have asked, so we have developed a six-point checklist Customers often ask whether or not they need to add oil to an air conditioning compressor they purchase from us. That's my suggestion. Ignorant people do stupid things, check your technicians certifications before trusting your system to possible damage. Hood and hatch are open, passenger doors are open and front doors have the windows open. Those sniffers are very senitive and the tip can be ruined/tainted real easy. Powered by UBB.threads PHP Forum Software 7.7.1. How do you test an A/C system, in December? But, how do you test the A/C system in your shop in December, in Michigan or anywhere else it's winter and cold? As a Ford trainer and as faculty in Ferris State University's Automotive Program, I often had to teach A/C classes in November, December, January, February and March in Michigan. The A/C system is tasked with transferring heat energy out of the hot cabin and out to the atmosphere. Engine coolant temperature conditions are within normal parameters. 196419651966196719681969 1970197119721973, 196619671968196919701971 197219731974197519761977 19781979, 195519561957195819591960 196119621963196419651966, 194819491950195119521953 195419551956195719581959 196019611962196319641965 196619681969197019711972 197319741975197619771978 1979, 196719681969197019711972 197319741975197619771978, 195819591960196119621963 196419651966196719681969 197019711972197319741975 1976, 195519561957195819591960 196119621963196419651966 19671968, 195819591960196119621963 19641965196619671968, 196219631964196519661967 196819691970197119721973 19741976, 194719481949195019511952 195319541955195619571958 195919601961196219631964 196519661967196819691970 197119721973197419751976 197719781979198019811982 19831984198519861987, 196919701971197219731974 197519761977197819791980 198119821983198419851986 198719881989, 197719781979198019811982 198319841985198619871988 1989, 197519761977197819791980 19811982198319841985, 196119621963196419651966 196719681968196919701971 1972197319741975, 196119621963196419651966 196719681968196919701971 1972197319741975, 195919601961196219631964 1965196619671968. Ive done AC since the 80s.You pull a vacuum and let it set.See if it drops.Then you add a small charge and use either a black light or leak detector.I prefer the light as the dye is easy to see.If you have a leak you usually reclaim the 134 you put in.We did have a 12 machine at work but it hadnt been used in 5 years.I might have a heater core.I cant remember if I scraped the heater setups from my 70 Imps.Rocky. Figure 5 - There are choices for identifiers, this one is showing that the system has 100% R-134a in it. Therefore you must do all testing inside a heated building. If you're an old-school tech like me, you were likely taught that you open the hood, connect the gauge set, fire up the engine, set engine rpm to 1500, A/C controls set to max-cold and max-fan, doors open and check the pressures. As with any article or other automotive technical training, there is no perfect, works every time it's tried method of repairing cars. Diagnostic strategies for problem vehicles, Living in a vacuum: Crankcase ventilation system testing, COP Ignitions What goes wrong, and how to test them. Make repairs as necessary and rerun the performance test to confirm repairs. I have heard of 250 PSI damaging low side components (evaporator) but maybe it was already on its way out. Aluminum components and seals are particularly vulnerable. These answers are coming. You can breathe on it and set it off. -After charging, electronic leak test. It was reading under hood temperature. That way, what I say will make sense to all. And How did I know that the newly installed A/C system worked correctly? Pressure equalization is what happens to the operating high and low side pressures (they equalize) when the system is shut off. One of the primary sensors for the control of the system was the ambient temperature sensor, in front of the condenser, behind the grille. Leak testing using an electronic testerElectronic leak detectors can be particularly useful in finding very small leaks. Note: These two steps are why you check service publications early in the process to find out test procedures, any TSBs, system operating strategy, and specifications. By comparing this to your chart for R-134a this is a good indication that what is in the system is R-134a and there is enough refrigerant in the system to begin testing. http://www.ackits.com/index.php?route=product/product&product_id=31708&search=big+blu-------------------------, I found the leak in a hose leading to (or away from) the compressor. We use cookies to optimize our website and our service. Federal regulations also require that for each type of refrigerant that you service in your shop you must have a unique and dedicated recovery-recycle machine. Note, running it longer than 30-45 minutes will likely remove even more moisture but you reach a point of diminishing returns. The low or low pressure side is from the expansion valve through the evaporator and back to the compressor. Wires disconnected? Evacuation Purpose #3: Removing Moisture Moisture removal is arguably the most important purpose of evacuation as moisture is the leading cause of AC system failure. You will also want to keep in mind that certain vehicles with R-1234yf may be regulated under OBD II emissions. . His thinking: I checked for leaks, now Im moving on to the next step. He was not only evacuating and charging without a license but without any understanding of what he was doing. Wide Open Throttle (WOT) condition is not present. Pass the probe under the suspected leak area starting at the highest point in the circuit (refrigerant gas is heavier than air). Here's one example of the types We've been working on classic cars for several decades now, so we've got a good picture of the quality of thousands of different parts made by scores of manufacturers. You cannot fix that car without access to service publications and a scan tool and/or J2534 pass through. Let's review a good procedure for any time you test the A/C system, starting with the legal requirements. If something is not right (airflow across a heat exchanger, the flow of refrigerant in the system, and passing the restriction, or lack of one), all of these concerns create an effect on pressure readings. A good visual inspection can find many problems. If there is vacuum loss of 2 or greater, there is probably a leak. You're saying, "Wait, this seems like the process I use in the summer." 2. If you found that the system contains two or more refrigerants, consider it to be contaminated. I always like to baseline my training so everyone is on the same foundation. Modifying those vehicles A/C systems may fall under emissions tampering. Certain performance issues will keep the PCM from turning the A/C compressor on (Figure 7). Electronic controls and the possible concerns that may be caused by skewed sensors, faulty programming, and drivability issues are each worth their own articles. This is one of those procedures, based on my training and my experience that works nearly every time it is tried. Re: How can I pressure test the A/C system? A frantic call to the service department and the first available appointment later and I was doing A/C work. 2022 Endeavor Business Media, LLC. At first, everything was fine. 10. Using service publications prepare the vehicle for testing. Initial leak check 2. For approximately the last 30 years, the A/C systems (both manual and automatic systems) have an HVAC module in communication with the Powertrain Control Module to control compressor and cooling fan operation. On a constant running system you read the gauges after the system has stabilized. Covering over 15,000 models from 80 vehicle manufacturers, Autodatas systems ensure that professional workshops have access to the most accurate, relevant and up-to-date manufacturers information needed for service, repair and diagnostic work, in the shortest possible time. AC system evacuation serves three purposes: 1. The high or high pressure side is from the compressor to the expansion valve. Connect a scan tool and see if there are any DTCs from the HVAC system or PCM that may be keeping the system from operating. NOTE: With a partially charged system it is advisable to run the air conditioning system for only a short period and not to exceed engine idle speed, as there may be insufficient oil to sustain lubrication of the compressor. I'll explain why that is critical in just a moment. 11. The exception to that is a recovery mechanism that is only used to recover contaminated refrigerant. In this article I have focused on just testing the refrigeration part of the AC system. POA - an abbreviation for Pilot Operated Absolute - valves are Well, we've done it again! 10 to 15 bar (sufficient for leak testing purposes), and close the valve. The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes. https://www.facebook.com/AutoBodyRepairNetwork/, https://www.instagram.com/ptenmagazine/?hl=en, https://www.linkedin.com/company/40735491/, https://www.youtube.com/channel/UCxBEkpoYgmG0r34_B3mOr4Q. Follow the OEs service procedure, be ready to fix seemingly unrelated concerns, and for refrigerant concerns, rely on the performance test. I didn't know about the pressure equalization thing. NOTE: A leakage rate of between 50 and 100g of refrigerant per annum is normal. A wonky example ..at 24.04 Hg of vacuum, water boils at 140 degrees Fahrenheit. I mentioned that sensors that can cause problems. Don't actually own a tank of that (yet, anyways). Start the engine and operate the air conditioning system. This TSB directed the techs to evacuate the system and recharge with a specific amount of refrigerant. While there certainly were and may still be some cars that require you to do that, many today don't work that way. After about 10 minutes I noticed the air blowing out was getting colder and colder, and I heard the A/C clutch engage. Otherwise, it wasn't until sometime in spring when the temperature and humidity went up and people turned their systems on, and nothing happened. With the success of all of our D.E.R. The way you test an A/C system in December is the same way you test the A/C system in every other month of the year: by the book. Always make sure the caps are on and secure. The answer? By taking a little care with your air conditioner over the winter months, you 2021 Classic Auto Air Air Conditioning & Heating for 70s & Older Cars & Trucks - All rights reserved, Auto Air Conditioning Evacuation: Not Just Testing For Leaks. I have all the equipment I think I'll need (bottle, regulator, fittings, ac manifold) to do this, though I'm just a little unsure how to proceed with it. Figure 8 - This 2005 Ford Explorer is ready for a performance test. The next step is to set engine speed to spec and monitor outlet temperatures and note pressures to compare to the chart to determine if the system is working as designed. To summarize proper AC system evacuation: -Dont do it if you are not a licensed professional -New filter drier -Evacuate for 30-45 minutes at 28-30 Hg -Let the AC system sit for 10 minutes. Ensure that the air conditioning system is charged, a partial charge, approximately 225g is sufficient. Leak testing with bubble dye solutionFor basic leak detection (for instance in the area of connections) a bottle of commercially available bubble dye solution can be used. My caveat to, will this work every time? When you have high-temperature extremes, you may have trouble reproducing a concern. This can and does happen. The longer the evacuation, the more moisture will be removed. The dye can be added to the refrigerant system during repair, or during the evacuation process, depending on the equipment available. Using the performance test results and the associated charts in service publications the testing procedure would find them or put them on the right course to find them, every time. Classic Auto Air has always taken pride in the fact we have an extensive quality control process. This site requires you to register or login to post a comment. Your email address will not be published. CAUTION: Excessive ultraviolet light can damage eyesight. Required fields are marked *. If an air conditioning system requires frequent charging, a leak test should be carriedout. the leak testing is done with the system not running so would expect the pressures should equalize regardless of witch side you add to but you can probably confirm this with your gauges and add to both sides if needed and you will be just using the 1 pressure to test both sides, while I have never used nitrogen for leak testing I see 175 -200 psi recommended.