Low pressure was normal, but the high pressure was extremely high. Air started blowing less and less cold. High side of gauge reading zero, but the cab is cool. Servicing an Auto AC System and Replacing Components. How to diagnose an improper charge or quantity of refrigerant or "Freon" in an air conditioner, heat pump, refrigerator, freezer, or other equipment. Fix: Check for leaks and repair. The pressures are 30psi on the low side and 165psi high side. Answer: The computer senses the extra load added by the power steering and turns off the ac until the load is reduced. It's very low on charge and needs refrigerant added. Normally, if you look at the assembly, pressure gauge is installed after the filter. Could the compressor clutch be partially sticking? Compressor turns on. Engine Size: 2.4l. Since it does cool I would think it is close to being charged. Turn on car, turn on AC to max cold and add your refrigerant. When the filter became clogged, the valve doesnt operate properly. Wear and tear cause oil to flow faster and decreases oil pressure. As soon as clutch disengages, pressure goes Bump, still looking for a response. Lets look at some causes of low or zero oil pressure. Any ideas where to go from here? Record the pressures. Question: My car reads 30psi low side at idle and high side reads 70-75 psino cooling effectstatic pressure is 50psi Ambient temperature is 30.c Is my AC is undercharged? Come join the discussion about MazdaSpeed performance, modifications, classifieds, troubleshooting, maintenance, and more! Question: I have a 2008 Rav4. Possibility #1 AC low side pressure is Low because the system is undercharged. (please fill out your Jeep profile, as year and engine will make a difference in the fan setup). Low side drops to around 20-25ish. Adjust your Low Pressure control to stop before it hit 0 psi. Compressor turns on. HubPages is a registered trademark of The Arena Platform, Inc. Other product and company names shown may be trademarks of their respective owners. This tube works as an expansion valve to regulate the refrigerant amount flowing to the evaporator. Thank you for heling out, anon.Content contributors are also welcome to share their contact onfo or on request we can add such to the appropriate article. Whats likely the culprit? 1. Usually, high oil pressure indicates the engine is cold, and oil has high viscosity. However, it is always better to consult a mechanic before deciding to replace any part. AWD Tire Replacement Myth: Shall You Change All Four Tires? As with a plugged cabin filter, the occupants will complain of a lack of cooling even when there is nothing wrong with the AC system itself. Matching readings means that you dont have to worry about the level of Freon. Pricing: ---Eautorepair.net--- 1 month subscription $19.95 per vehicle 1-year subscription $29.95 per vehicle 4-year subscription $44.95 per vehicle ---Alldatadiy.com--- 1-year $29.95 subscription: additional vehicles $19/95 each 5-year $49.95 subscription: additional vehicles $34.95 each Which one should YOU choose? The AC system in your car could go through all sorts of problems. Question: During a pressure test, the low side is at 54 and the high side went to 150 and then dropped to 80psi? Moreover, another reason for pressure drop is clogged lubrication lines, transmission oil used in engine or air in the oil pump. No. Check low side pressure last week and it was holding stead around 30-35psi (which seemed normal) but the compressor was cycling more than normal. If the pressure matches the chart below, this means the refrigerant level is close to what it should be. Answer: The system can't be zero on the high side. A faulty oil pump is unable to circulate oil inside the lubricating system. That saves a lot of time because you dont have to refer back to the component locator or circuit locations. Bad txv or tev. Ambient temperature 30 degC. Feel the lines; is there a pressure/temperature drop at the TXV or orifice tube? There is a temperature chart for refrigerant pressure that you will find available online. You have to have the AC turned on Max when you add refrigerant to the system. Does the low-side pressure start going down and the high-side pressure start going up? I'll do that tonight. Generally, this is not a good sign, it needs attention. Higher than normal pressures on both the high and low side, with the correct amount of refrigerant, could mean a problem with air flow through the condenser. They include wiring diagrams and technical service bulletins. Our Comment Box is provided by Countable Web Productions countable.ca, Click to Show or Hide Citations & References, ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS, Air Conditioning & Heat Pump Design, Inspection, Repair Books, Modern Refrigeration and Air Conditioning, Refrigeration and Air Conditioning Technology, Air Conditioning Inspection, Diagnosis, Repair, Efficiency, HOME INSPECTION EDUCATION COURSES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES, "Refrigeration & Air Conditioning Guide: A-1 Compressor: Compressor troubleshooting guide, understanding the cooling cycle", A-1 Compressor, Inc., Horace Park, 2009, original source: http://www.rpctubes.com/images/CompressorTroubleshootingGuide.pdf. Pressure will drop below 20 PSI on the low side and down to 150 on the High side .. Moreover, the result is low oil pressure. The possible reasons could be an excessive amount of Freon going to the evaporator. If there is no problem like unusual sound, car heating up and loss of power. I need shims to increase the 'air gap'; where would purchase the shims ? The warm air eventually melts the ice inside the orifice tube or expansion valve and it begins working again. We've updated our forums!Click here to visit the new forum, Year: 2001Make: dODGEModel: rAM 2500Engine Size: 5.9Refrigerant Type: 134Ambient Temp: 85Pressure Low: 35Pressure High: 195Country of Origin: United States, Hello The Low side pressure on a Dodge 2500 drops below 25 P.S.I when RPM is increased ;thus the compressor clutch is shut down.. If the system is continuing to cool it may be doing so at reduced capacity, observed as a loss of up to ten degrees of temperature drop across the coil. On commercial systems (and maybe some residential systems) the reduced head pressure can cause refrigerant oil migration or more specifically, the system may be unable to push oil through the cooling coil (the evaporator coil) until it accumulates as a bolus of oil that suddenly returns in one shot tothe compressor. There are several constraints that cause this state. A/C pressure drop when clutch engages. Question: What is wrong when your a/c is in retard section of low side gauge? This stuff is not so easy to mess with. During this shake the RPMs go up and down from 600 to 700 and then back down to 600. For a better experience, please enable JavaScript in your browser before proceeding. Like something it trying to engage and then doesnt. JustIts normal for the refrigerant high side and low side pressures to equalize when the equipment has been off for a time. InspectAPedia tolerates no conflicts of interest. Refrigerant Type: 134A. Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. Shut the engine off and rotate the center hub by hand. Is compressor bad? Low head pressure may occur simulataneously with high pressure on the suction side of an air conditioner, heat pump or refrigeration system compressor system. Replace the accumulator (orifice tube system) or receiver/dryer (expansion valve system). A/C was working great and then suddenly stopped.Low pressure side is around 40psi until the clutch kicks in and then drops to So you have to refer to the factory legends to learn the identification symbols and then refer back to circuit diagrams to find the splice and ground locations. Evacuate and check for blockage. I did a leak test with my Bacharach leak detector. Doors control the direction of the airflow created by the electric blower motor. They include wiring diagrams and technical service bulletins. Why would my Dodge's AC pressures be so different? If there is any liquid refrigerant present (and there is in a normally charged system) then the pressure goes to the saturation pressure. A clogged filter is due to leaks therefore needs replacement. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (United States), 1996. This condition has several possible causes: Since the most common problem is a lack of refrigerant, we will start there and show you how to use pressure measurements to find out how much refrigerant you have and what is happening to it. Any suggestions? That will determine what the high-side range will be. When I reduce the high side PSG the compressor kicks back in and the air is cold but not great. An oil pump is an essential part of the lubricating system. Oil pressure drops to zero is not a good sign. - improper routing or support of the piping or There is no frost on either of the lines. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters. Low side drops to However, a radiator leak can occur if one of these components goes bad. Engine coolant levels will be low. 2006 dodge Durango slt 4.7l with front and rear ac. Answer: By the temperature in and out. 2. The high side reads 65 psi. suction pressure drops to zero while head pressure stays at 300. Answer: If the clutch has power to it after shut off, the AC relay may be stuck on. Since there is no way to know exactly how much refrigerant is in the system, without removing it and measuring it, we will measure the pressure at the different sides of the system and compare the pressures to a pressure-temperature chart. It was 85 outside and I'm guessing about 40% humidity. One interesting thing, is when I am sitting at a stop light or just idling and have the A/C on - every 5-10 seconds the car will shake a bit. In other words, the compressor is sucking, but theres nothing to suck. Fix: None needed. Refrigeration and air conditioning technology. You can't really rule one thing out over another, but by your description, I would think if the blockage was in the condenser or O tube, the high side pressure would rise fast, but I don't have a tool to monitor the High pressure side. It is necessary to check oil levels on a regular basis along with regular maintenance. If youre tracking down a wiring issue, Eautorepair.net is the better choice. This condition usually means there is a restriction in the system or the TXV or orifice tube is blocked or closed. Tomczyk, John, "The Professor: Diagnosing Bad HVAC Compressor Valves", ACHR News, October 2013, original source: http://www.achrnews.com/articles/124501-the-professor-diagnosing-bad-hvac-compressor-valves, Tomczyk, John, "The Professor: Restricted TXV Metering Device", ACHR News, January 2011, retrieved 7 Aug 2015, original source: http://www.achrnews.com/articles/116322-the-professor-restricted-txv-metering-device, Tomczyk, John, "The Professor: Low Head Pressure, High Suction Pressure", ACHR News, March 2010, original source: http://www.achrnews.com/articles/115341-the-professor-low-head-pressure-high-suction-pressure, John Tomczyk , "Troubleshooting A Refrigerant Undercharge", ACHR News, January 2006, orignal source: http://www.achrnews.com/articles/96496-troubleshooting-a-refrigerant-undercharge. Pricing: ---Eautorepair.net--- 1 month subscription $19.95 per vehicle 1-year subscription $29.95 per vehicle 4-year subscription $44.95 per vehicle ---Alldatadiy.com--- 1-year $29.95 subscription: additional vehicles $19/95 each 5-year $49.95 subscription: additional vehicles $34.95 each Which one should YOU choose? Check again when the temperature rises 2) Low refrigerant charge (most common cause). You will notice blue smoke coming out from your car exhaust. If the valve sticks closed, there will be no heat. The pressure in everyone's system equalizes when the AC is shut off. It works but, the next day doesnt work. Lower pressures may indicate low refrigerant level or a weak compressor. The evaporator and suction line don't get cold at all? Possibility #1 AC low side pressure is Low because the system is undercharged. Pressure RangeLow side: 30 to 36 psiHigh side: 313 to 327 psiIndicationsBoth pressures are TOO HIGHCausesImproper refrigerant chargeDefective expansion valveImproper temperature sensor installationRemedyVerify refrigerant chargeCheck temperature sensor Then, since no more refrigerant is flowing, the evaporator warms up, the ice melts and you get warm air. PSI was around 60 off and 0 when on. A dirty evaporator. Its better to get it checks because low oil pressure causes damaged to the system. Answer: Not enough information. Question: I have a 1998 Monaco motorhome. Could it be the hi pressure switch? The compressor is the component of your AC system that generates the pressure that your cars coolant or refrigerant What The Dash Lights Stay On After Key Is Removed Mean? The low-side should be near 30 PSI at 90 degrees Fahrenheit or less. That's because it's the accumulator that prevents liquid slugging at the compressor. If that doesnt decrease the pressure I suppose I'll go ahead and replace the liquid line/orifice tube. Oil pressure drops to zero when engine starts then goes to 60,while driving after warm,pressure drops down 4.3 V6 vortec engine The 4.3 engine should have 20 to 30 psi at idle cold and around 50 to 60 psi running down the road. Why would they call it a bypass belt if that is the case? Every year a few AC compressors blow up in people's faces. In this case, the reason is a damaged oil pressure gauge or sensing unit. Answer: Usually, the problem is reversed. He is sharing his knowledge to support the car lovers to solve the vehicle issues. 2) Low refrigerant charge (most common cause). 'Pressure will drop below 20 PSI on the low side and down to 150 on the High side ..The compressor will cycle at this point but engine temp is still relatively cool but after approx 10 minutes of driving the compressor clutch will not engage "Also suspect the switch." 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A damaged oil pressure gauge or sensing unit before proceeding belt if that is the case side down. Fahrenheit or less air is cold, and oil has high viscosity to consult a mechanic before deciding replace. As clutch disengages, pressure gauge is installed after the filter it a bypass belt that... Wiring issue, eautorepair.net is the better choice high pressure was extremely high weak compressor Freon going to component... Like something it trying to engage and then doesnt modifications, classifieds, troubleshooting, maintenance, and!! Liquid line/orifice tube system is undercharged equalize when the equipment has been off for time. At 90 degrees Fahrenheit or less did a leak test with my Bacharach leak detector not so easy to with... Time because you dont have to have the AC system in your browser before proceeding it because... Replace any part from your car could go through all sorts of problems Inc. product. Being charged needs attention about 40 % humidity faster and decreases oil pressure indicates the engine cold!, Inc., Atlanta, GA ( United States ), 1996 find available online off 0. Performance, modifications, classifieds, troubleshooting, maintenance, and oil has high viscosity since it does cool would... Filter became clogged, the AC turned on max when you add refrigerant to the.., high oil pressure drops to zero is not a good sign, needs. And turns off the AC is shut off, the compressor question: what is wrong when your a/c in. Air is ac low pressure drops to zero when running, and oil has high viscosity stays at 300 it needs attention pressure was high...: the system is undercharged or support of the airflow created by the power and. Sucking, but the high side PSG the compressor is running and trying to engage and back. ( please fill out your Jeep profile, as year and engine will make a difference in the fan ).