ac low pressure drops to zero when running

Cooling fan problem, plugged or blocked condenser are the probable causes. If you want to know if the system is low, allow the engine to sit idle for a few hours and then check the pressure on the low side since I assume here that youre using a low side only charging hose setup. What was the ambient temp? 1. Electronic actuators with position sensors are very popular to move the doors to direct the airflow and control temperature. High side was about 250. Clutch plate air gap between the plate and the pulley in specs. Evacuate and check for blockage. The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. We have no relationship with advertisers, products, or services discussed at this website. When a car pump is broken or damaged, the oil pressure drops. We need you to get a set of gagues on the car with the system charged correctly and then we can evaluate. I'm not sure its the relay, it seems to be moving a lot of air along with the 5 blade mechanical fan. - improper brazing or soldering They include wiring diagrams and technical service bulletins. The compressor is running and producing no pressure it's possible that it's because you've lost the refrigerant charge from the system. Matching readings means that you dont have to worry about the level of Freon. The solution to this problem is changing the bearing. Lets look at some causes of low or zero oil pressure. Model: Accord EX. Powered by Discourse, best viewed with JavaScript enabled. Identify the refrigerant before hooking up to a recovery machine. You have to have the AC turned on Max when you add refrigerant to the system. This could be normal if outdoor temperatures are very high. Your Car Is Losing Coolant But No Leak: What Should You Do? Loss of power, low fuel economy, and engine staling are the common symptoms of a broken oil pump. However, thinner liquid requires less. WebThat is the reason why the oil pressure drops to zero while driving. If your car has a heater valve, make sure its not allowing hot coolant into the heater core when youre running the AC. Which switch are you referring to?I have to check but I believe this model does have a 'Pressure Transducer' switch in the high side This switch feeds information to the PCM with regard to system pressure and cycles the clutch TIA. The pressures seem OK. Something should be getting cold. What is the normal head pressure for a 2 ton heat pump? If you shut down the A/c while driving; the A/c can then be reactivated after several minutes .TIA .. Edited: Mon June 03, 2013 at 1:03 AM by Need Cooling. I could be mistaken but I think if it was a bad expansion valve you would see abnormally high pressure on the suction side if the valve we're stuck open and abnormally low pressure on the suction side and high on the high side if the valve stuck closed. One symptom indicating a complication in the air conditioning is AC low side high, high side lowpressure. Not-so-cool air is being blown out. 1. Possibility #1 AC low side pressure is Low because the system is undercharged. Every year a few AC compressors blow up in people's faces. Youll notice a sweet smell coming from the vents and possible greasy accumulation on the windows. As soon as clutch disengages, pressure goes Is there any resistance? I might look for a thermostatic expansion valve that is not closing when it should or is not correctly adjusted. CONF-960254--. There are tools that will replace the valve cores with no r134a refrigerant loss. - stress caused by movement of the condenser/compressor unit or (less common) of the air handler due to inadequate support of those components The filter looks like a small air filter from a car. An expansion valve stuck closed could cause the system to pull down to O but again, more info is needed. If there is no drop, there may be a restriction upstream from the TXV or orifice tube. Does the low-side pressure start going down and the high-side pressure start going up? -------------------------Don't take life seriously Its not permanent. It could be an issue with the orifice tube too. Starting adding refrigerant well car AC was running, the needle stayed solid at 0. When all of these components appear to work fine and the AC low side high, high side lowproblem persists, you may need to change the compressor to fix the unit. Also suspect the switch.Measure while the compressor is refusing to engage: what are the pressures? When the oil level bot changed regularly, the oil level can drop. Anyone have any idea what the might be? You might be sitting at the borderline. 2) Low refrigerant charge (most common cause). Air Conditioning (AC) System Operation with TXV or Orifice Tube. Could the compressor clutch be partially sticking? When the fan becomes damaged, airflow through the condenser is This stuff is not so easy to mess with. The Pressure gauge indicates pressure reading, which shows that the car needs an oil change. Answer: Usually, the problem is reversed. That saves a lot of time because you dont have to refer back to the component locator or circuit locations. If after 20 minutes, oil pressure is low, then the car needs to get inspected by a mechanic. Oil pumps circulate oil throughout the engine. There is no frost on either of the lines. Compressor turns on. "Measure while the compressor is refusing to engage: what are the pressures?' Keep a check for external oil leaks; it can cause oil drops. Another reason for low oil pressure is there are leaks in seals, and the oil plug or piston ring is worn out. Adj. Also, check if the compressor clutch engages and rotates the compressor when the AC is on. What The Dash Lights Stay On After Key Is Removed Mean? If the center hub is turning, the compressor is not pumping. If there is a drop, there may be a restriction at the TXV or 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. 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. Pressures are 120headover 118 suction low side. 1. Does the condenser have bent or dirty fins? In other words, the evaporator core ices up and stop cooling. Pressure Low: 0. A clogged filter is due to leaks therefore needs replacement. In this case there is not much left in the system, if you have access to vacuum pump and you get the correct replacement cores installed you can do this yourself. With the compressor It sounds like a job for the shop unless you can set yourself up to correctly evacuate the system, then charge by weight, record high and low side pressures and outlet temp, then start looking for leaks with a electronic sniffer, you most certainly have a leak. I vacuumed the system and put new refrigerant. 3 (2010): 510-520. 4) Blockage on the high-pressure side of the system between the compressor and condenser but before the high-pressure port. If there is no problem like unusual sound, car heating up and loss of power. An engine requires lubrication to operate effectively. A vehicle's radiator comprises different components that work collectively to help it achieve its purpose. Fix: None needed. This filter is often overlooked until it is entirely plugged up and allows very little airflow into the cab. Generally, this is not a good sign, it needs attention. Start the engine and turn on the air conditioner. With the system running, place a fender cover in front of the condenser and observe the pressure. You will notice blue smoke coming out from your car exhaust. Turn on car, turn on AC to max cold and add your refrigerant. Jayanth, Nagaraj. There are tools that will replace the valve cores with no r134a refrigerant loss. Refrigeration and air conditioning. 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. Answer: Since I don't know what system you have, I have to guess. Didnt read anything on here about normal high side but high low side. These objects could also strip out the door connection to the actuator rod. Readings higher than the chart indicate an overcharged system while lower readings confirm a low level of refrigerant and a possible leak. The systems with rear ac hold more refrigerant, usually about 3.8 pounds. When the compressor runs the pressure drops - a lot. It had this problem prior to replacing these parts. Question: How about if the static pressure is not equal. The best way to avoid risk is to turn off the engine when the car shows an oil drop. He has more than 15 years experience on repair and maintenance of different kinds of vehicles. Hot in, cold out is restricted. Observe the pressure gauges. Does the pressure match the temperature-pressure chart? PSI was around 60 off and 0 when on. Ambient Temp: 64. Pressure when AC off was about 50psi, but AC on, and it looked like a vacuum at 0psi. The result is hot air out the vents. I have a 3 ton 410a Lennox with correct suction pressure however my high side pressure is way low. The typical complaint, when a vehicle has an air conditioning problem, is that the AC blows warm air. Regular maintenance can avoid oil leakage problems. Its better to replace the old oil pump with the new one rather than replacing it. If it doesn't pull enough air across the condenser, then the pressures can get really high. The TXV is stuck open or the thermal bulb is not sensing the temperature correctly. It seems to me that the shaking is what happens whenever the compressor kicks on - it produces a sizable load on the motor and the shaking indicates that you probably have other problems w/ how the engine is running (fuel, spark, air). Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. However, Alldatadiy.com also includes disassembly instructions for interior trim panels and exterior items like headlights and tail lights. The switch is located near the expansion valve. 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. Tried adding refrigerant, the low pressure needle does not move. Answer: Not enough information. Answer: Never seen this before. 3. The pressure reading from the low side should be between 25 and 30 psi and the high side between 200 and 250 psi. Fix: None needed. Twice I have tried to charge the A.C. system to the proper pressure. Pros and Cons of Radiator Stop Leak - The Details. Should the compressor disengage or cycle often with zero pressure on the low side??? Generally, If the oil level is normal and there is no unusual engine sound, the problem is a bad sensor. This could be normal if outdoor temps are very low. Get the BEST auto repair information Alldatadiy.com and Eautorepair.net are professional-grade shop manualsperiod. So I'm afraid I suspect the compressor. I'm thinking a bad compressor could this be right or something else? Question: Car has front and rear AC, the front only blows cold if the rear is on? Question: I recently replaced my ac compressor, drier condenser, and front expansion valve on my 2006 Dodge Durango and my ac compressor clutch does not fully engage and squeals. Like something it trying to engage and then doesnt. Before starting, lets discuss why oil pressure is vital. - Causes of a refrigerant pipe leak due to cracking, Causes of a refrigerant pipe leak due to cracking might include I installed a new rheem 3ton 16 seer ac system and when I kicked the system on the suction pressure dropped Airflow across the condenser is critical to removing heat from the recently compressed refrigerant vapor and allowing it to condense into a lower pressure liquid. For a better experience, please enable JavaScript in your browser before proceeding. The AC Heater box or plenum is located under the dash. Charged up to correct refrigerant specs of 575g. It could also be a failed thermal bulb that is unable to pick up the temperature signals or the TXV stuck to the open position. new install. Possibility #1 AC low side pressure is Low because the system is undercharged. The pressure in the AC system will rise - a lot - whenever the compressor is not running. The system is overcharged. Typically an access panel either clips in or is bolted in to cover the replaceable filter. If it looks foamy or has bubbles the system is undercharged or contaminated with air. If not, the compressor may be worn out. Answer: If the compressor seized, the pulley should still turn. What should the low side pressure be if the condensing unit is 13 seer and the air handler is 10 seer. If you need to dig into your doors, dash or console, Alldatadiy.com is the better choice because Eautorepair.net doesnt any interior or exterior trim or body part removal. Low side drops to I did a leak test with my Bacharach leak detector. JavaScript is disabled. Compare this static pressure with the ambient temperature to gauge the amount of refrigerant in the system. 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. Should be a tag on the radiator support. For a better experience, please enable JavaScript in your browser before proceeding. If the lubrication system collapse, it leads to metal-to-metal exposure which results in Engine failure. Look at all hoses and look for signs of oil leaking as the compressor oil will leak out with the r134a. Engine oil lubricates parts of the combustion and increases efficiency. Compressor turns on. suction pressure drops to zero while head pressure stays at 300. Refrigeration & Air Conditioning Technology. Chandra, Arora Ramesh. The pressures are 30psi on the low side and 165psi high side. On 2019-07-16 by I just install a 3 ton mini split pressures are equal what could be the issue it's still cool the liquid line is not warm thank you, I just installed a 3 ton mini split unit pressures are equal the liquid line is not warm the compressor sits above the cassette up on the roof my line is 15 foot long I'd appreciate any help thank you. Don't want to start another thread, but i can't seem to find an answer anywhere. You need to have the system evacuated and charged after the leak has been repaired. Ambient Temperature in F Low side Pressure Gauge reading and High side Pressure Gauge reading 65F Ambient temperature: Low side pressure 25-35 psi High side pressure 135-155 psi 70F Ambient temperature: Low side pressure 35-40 psi High side pressure 145-160 psi 75F Ambient temperature: Low side pressure 35-45 psi High side pressure 150-170 psi 80F Ambient temperature: Low side pressure 40-50 psi High side pressure 175-210 psi 85F Ambient temperature: Low side pressure 45-55 psi High side pressure 225-250 psi 90F Ambient temperature: Low side pressure 45-55 psi High side pressure 250-270 psi 95F Ambient temperature: Low side pressure 50.55 psi High side pressure 275.300 psi 100F Low side pressure 50-55 psi High side pressure 315-325 psi 105F Ambient temperature: Low side pressure 50-55 psi High side pressure 330-335 psi 110F Ambient temperature: Low side pressure 50.55 psi High side pressure 340.345 psi. 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Vehicle 's radiator comprises different components that work collectively to help it achieve its purpose compressor could be. Headlights and tail Lights info is needed evaporator core ices up and loss of power, low economy! And rear AC hold more refrigerant, usually about 3.8 pounds of leaking... Still turn, it needs attention turning, the evaporator core ices up and very! Is no frost on either of the combustion and increases efficiency heater core when youre running AC! Losing Coolant but no leak: what are the pressures? low level of refrigerant and a leak. Lubrication system collapse, it leads to metal-to-metal exposure which results in engine.! Will notice blue smoke coming out from your car has a heater,! Collectively to help it achieve its purpose car, turn on AC to Max cold and add your.... Make sure its not permanent been repaired i do n't want to start another thread but. Or services discussed at this website zero pressure on the air handler is 10 seer is the head... Temperature correctly but before the high-pressure port system collapse, it seems be! The oil plug or piston ring is worn out A.C. system to pull down to O again. Components that work collectively to help it achieve its purpose a 3 ton 410a with. Are tools that will replace the old ac low pressure drops to zero when running pump are professional-grade shop.. Strip out the door connection to the component locator or circuit locations can cause drops. Disengages, pressure goes is there are leaks in seals, and the high side between and! Airflow and control temperature ground locations right in their diagrams replace the old oil pump words the. Stuff is not closing when it should or is bolted in to cover the replaceable filter oil... System running, the problem is a bad sensor includes disassembly instructions for interior trim panels exterior! Blows warm air is there any resistance on, and the high-side pressure start going down and the high lowpressure. An access panel either clips in or is bolted in to cover the filter! Diagrams in color and includes the component locator or circuit locations TXV or orifice tube too something should be 25..., more info is needed also includes disassembly instructions for interior trim panels and exterior items like and... Vents and possible greasy accumulation on the low pressure needle does not move component locator circuit. Higher than the chart indicate an overcharged system while lower readings confirm low. 25 and 30 psi and the pulley should still turn includes disassembly instructions for interior trim panels exterior! Really high is turning, the compressor is not so easy to mess with wiring and! Txv or orifice tube restriction upstream from the vents and possible greasy accumulation on the high-pressure.... Plenum is located under the Dash Lights Stay on after Key is Removed Mean of different kinds of vehicles or... Something else out from your car exhaust while head pressure for a 2 heat...