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. 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. Evacuate the system and recharge with the correct amount of refrigerant. The compressor is the component of your AC system that generates the pressure that your cars coolant or refrigerant Refrigeration and air conditioning. It would not take any and I have the compressor clutch engaged with a hot wire. Lets look at some causes of low or zero oil pressure. Thus, this problem requires immediate care. Is there any resistance? Question: When I try to connect the coupler to the low side, it gives me a reading of 80-100 psi and it doesn't stay secure. Could it be the hi pressure switch? JustIts normal for the refrigerant high side and low side pressures to equalize when the equipment has been off for a time. The lower high side pressure may be from an undercharged system and the TXV is keeping the low side at 30 PSI. Answer: 1st we don't charge to a pressure, the system is filled to the proper capacity in pounds or kilograms. Possibility #1 AC low side pressure is Low because the system is undercharged. But the expansion valve or orifice tube is stuck or clogged so its not dispensing high-pressure liquid refrigerant into the evaporator coil. I'm betting there is a blockage though you really need a high side reading to tell for sure. A clogged filter is due to leaks therefore needs replacement. Also, check if the compressor clutch engages and rotates the compressor when the AC is on. Come join the discussion about MazdaSpeed performance, modifications, classifieds, troubleshooting, maintenance, and more! We also provide an ARTICLE INDEX for this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. Condenser fins are clogged, condenser fan isnt running or isnt running at the correct speed (most common cause). If it looks foamy or has bubbles the system is undercharged or contaminated with air. 7 Reasons Why Your Car Shuts Off While Driving and What To Do. Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. If the pressure is lower than in the chart, the refrigerant level is low. What was the ambient temp? 3. I'm thinking a bad compressor could this be right or something else? Lower pressures may indicate low refrigerant level or a weak compressor. That saves a lot of time because you dont have to refer back to the component locator or circuit locations. suction pressure drops to zero while head pressure stays at 300. As the vehicle accelerates, pressure is built that causes oil pressure to increase. With the compressor not running you should have 70+ PSI of pressure on the low side (this depends on ambient temperature outside, but at 70 degrees you'll see about 70 PSI, there are charts available via google). It creates problem for the oil pressure pump to operate effectively. Pressure that is too much lower or higher shows there is a problem. Lubrication system, lubricate moving parts of the engine. Compressor turns on. Is voltage being applied to the clutch coil? Then you can recover all the refridgerant you have put in and fix the leak then recharge and recheck. Model: Accord EX. I grabbed one of those recharge kits and monitored the Low side pressure. The Arena Media Brands, LLC and respective content providers to this website may receive compensation for some links to products and services on this website. If dirt, fuzz, leaves or plastic bags are covering the surface of the evaporator, the airflow will be reduced along with the cooling capacity. - stress caused by movement of the condenser/compressor unit or (less common) of the air handler due to inadequate support of those components Hot in, cold out is restricted. No. When its opening becomes bigger than the usual size, more refrigerant goes to the evaporator and creates pressure discrepancies. Twice I have tried to charge the A.C. system to the proper pressure. Question: The A/C compressor has seized on my 2000 Sienna. High side reading is normal but low side immediately pegged the gauge and didnt move. And because the Best Miata Soft Top Replacement | Protect Your Vehicle. I am sure it will cycle if all that is wrong is low freon. Fix: None needed. Turn on car, turn on AC to max cold and add your refrigerant. Majorly the problem is the broken oil pump. With AC on, it had 0 pressure and stayed that way for a couple of minutes well running. The Miata of Mazda has always been known as a great convertible from the late 90s. Regular maintenance can avoid oil leakage problems. AC didn't work when I purchased it, but I could see the compressor clutch engaging and disengaging. 3. Furthermore, If the pressure gauge indicates zero reading, it should be stopped at once. We have no relationship with advertisers, products, or services discussed at this website. I'm not sure its the relay, it seems to be moving a lot of air along with the 5 blade mechanical fan. - defective or mechanically-damaged copper tubing pressure switch may be the answer, I have mine set @21 psi on my 98 GMC, and it still cycles off and on at high speeds, but it will also freeze you out on a 100 day. The TXV is stuck open or the thermal bulb is not sensing the temperature correctly. Replace clogged orifice tube and flush hoses. I'll take a look at the clutch gap. compressor is a Sanden model U4833..Now that you mention the clutch, I did jump the low pressure switch after the clutch disengaged and the clutch juddered.. Both of the schrader valves are leaking. When running, but AC turned off, it had full pressure. CONF-960254--. I'm here for knowledge and to maybe give some. It means that the engine has a low oil level. "Static pressure" is measured when the system is not running. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (United States), 1996. Pros and Cons of Radiator Stop Leak - The Details. For a better experience, please enable JavaScript in your browser before proceeding. Oil pressure gauge goes up and down while driving. Sometimes high temperature causes oil pressure to drop. Did it speed up? On 2020-04-08 by (mod) Blockage on the high-pressure side of the system between the compressor and condenser but before the high-pressure port. High side was about 250. Does the condenser have bent or dirty fins? I pulled a vacuum on the system prior to charging. The Pressure gauge indicates pressure reading, which shows that the car needs an oil change. A dirty evaporator. The high side reads 65 psi. Usually, the high side is really high and low side really low. Any suggestions? Identify the refrigerant before hooking up to a recovery machine. Fix: None needed. The high- and low-side pressures should be equal. The high side pressure during cycling though is more difficult to explain in words. Like something it trying to engage and then doesnt. Starting adding refrigerant well car AC was running, the needle stayed solid at 0. AC Low Side High, High Side Low: Why Does This Happen? 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. The reason of oil pressure gauge fluctuates while driving is contaminant oil. Answer: Since I don't know what system you have, I have to guess. If youre tracking down a wiring issue, Eautorepair.net is the better choice. The rear ac uses a TXV/H-Block and it sounds like the valve is not working. Where else should I be looking? Air Conditioning (AC) System Operation with TXV or Orifice Tube, Servicing an Auto AC System and Replacing Components, An electrical problem that prevents the compressor from turning on. The system must be evacuated before charging. 3) The heater core is leaking warm coolant into the heater box. High side of gauge reading zero, but the cab is cool. Cooling fan problem, plugged or blocked condenser are the probable causes. Too much refrigerant is flowing into the evaporator. It could be an issue with the orifice tube too. The pressure reading from the low side should be between 25 and 30 psi and the high side between 200 and 250 psi. In most cases, their diagrams are right from the factory manuals. Oil pressure turning to zero can cause damage to the engine. 2. Lets understand what And no offense was taken. Should be a tag on the radiator support. Whitman, Bill, Bill Johnson, John Tomczyk, and Eugene Silberstein. There must be a connection problem with the high side coupler. A series of doors controls the airflow through the heater box or plenum. It should speed up when the A/C is turned on. For a better experience, please enable JavaScript in your browser before proceeding. Does the low-side pressure start going down and the high-side pressure start going up? Fix: Check for leaks and repair. Answer: By the temperature in and out. lubricating system majorly depends upon a pump, filter, and greasing line system. Low pressure was normal, but the high pressure was extremely high. The AC system in your car could go through all sorts of problems. When the oil level bot changed regularly, the oil level can drop. There are several constraints that cause this state. I bought this car used in the winter, and now that the weather is starting to change, Ive noticed that the A/C doesnt exactly work. One typical issue is the unit not blowing cold air, which could be punishing in hot weather. Cengage Learning, 2012. The work I did on the system is : Changed the A/c dryer and changed the orifice line from the evaporator to the condenser ..This Dodge has a non removable orifice ;so the entire line has to be changed . The low-side should be near 30 PSI at 90 degrees Fahrenheit or less. However, Alldatadiy.com also includes disassembly instructions for interior trim panels and exterior items like headlights and tail lights. The filter looks like a small air filter from a car. Dexter, Arthur L., and Mourad Benouarets. - improper brazing or soldering Question: I have a 1996 Dodge Ram Diesel. WebThat is the reason why the oil pressure drops to zero while driving. Fixing Pump Wear: If the oil level on the dipstick is between high and low, but the engine is running noisily, the pump could also be worn. Question: Car has front and rear AC, the front only blows cold if the rear is on? The pressure in everyone's system equalizes when the AC is shut off. "Air-conditioning servicing system and method." WebWhat is normal automotive air conditioner pressure? It works but, the next day doesnt work. A faulty oil pump is unable to circulate oil inside the lubricating system. What could be the problem? Question: I have a 2010 Nissan Altima that I change the compressor,expansion valve, condenser and switch. Possibility #1 AC low side pressure is Low because the system is undercharged. Generally, people ask what to do when oil pressure drops to zero while driving? It's very low on charge and needs refrigerant added. Fix: Evacuate the system. Low HVACR compressor head pressure diagnosis: What are the causes of low head pressure at the air conditioner or heat pump compressor? These objects could also strip out the door connection to the actuator rod. This is the second part of a series on AC pressure gauge readings. The filter may be located under the dash or on the heater box in the engine compartment. When I reduce the high side PSG the compressor kicks back in and the air is cold but not great. When the pressure drops, it is an indication that something is wrong with the lubricating system. Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the. Check again when the temperature rises 2) Low refrigerant charge (most common cause). Air Conditioning (AC) System Operation with TXV or Orifice Tube. Question: 2020 mustang air works when it wants to. Descriptions: AC running @ 2000 RPM Low side drops to ZERO PSI on gauges, high side come up to about 165 PSI A Little wobble on the high side, but not a lot like Compare this static pressure with the ambient temperature to gauge the amount of refrigerant in the system. Pressure High: 65. Moreover, when there is no oil pressure, friction between moving parts increases causes engine performance to decrease. After the system runs for a while, raise the RPMs up to about 1,500. A clogged filter leads to extended oil and thus result in poor combustion. Actual readings will vary according to ambient temperature. Install an in-line filter to prevent re-occurrence. Without knowing static pressure this is a guess. I would stop messing with it now and take it to an AC specialist. WebCauses of oil pressure drops to zero while driving Low oil pressure is an indication that there is something wrong with the lubricating system. What you describe sounds like it might be normal operation of a system low on refrigerant. Can the compressor build the pressure? No other leaks were found. link to Pros and Cons of Radiator Stop Leak - The Details, link to Best Miata Soft Top Replacement | Protect Your Vehicle. There is no frost on either of the lines. Answer: Sounds like you have a leak. 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. Here are two companion articles you will find useful if you repair AC systems. Oil pressure is responsible for the longevity of the engine. Adjust your Low Pressure control to stop before it hit 0 psi. Engine coolant levels will be low. Then charge her up. I would say there is something wrong with the gauges. Answer: Usually, the problem is reversed. Then, since no more refrigerant is flowing, the evaporator warms up, the ice melts and you get warm air. Youll notice a sweet smell coming from the vents and possible greasy accumulation on the windows. Many vehicles today have a cabin filter to filter the incoming air from outside the vehicle. 2. So replacing the defective pump or gauge will be a good idea. In this case, the compressor is running and try to remove refrigerant gas from the evaporator. However, theres also the possibility that the system has gotten overcharged with too much refrigerant. If the pressure is zero, that means the system is at atmospheric pressure and has a If the center hub is turning, the compressor is not pumping. However, Alldatadiy.com also includes disassembly instructions for interior trim panels and exterior items like headlights and tail lights. Question: What causes the hig side pressure to be low? I plan to recover the 134A replace the schrader valves, pull a vacuum and recharge the system per Honda details on sticker. What is up with the high side? Another reason for low oil pressure is there are leaks in seals, and the oil plug or piston ring is worn out. On the other hand, there is possibly a huge leak when the pressure is zero. Loss of power, low fuel economy, and engine staling are the common symptoms of a broken oil pump. Start the engine and operate the AC system. Readings higher than the chart indicate an overcharged system while lower readings confirm a low level of refrigerant and a possible leak. Engine oil lubricates parts of the combustion and increases efficiency. 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. I installed a new rheem 3ton 16 seer ac system and when I kicked the system on the suction pressure dropped Even small amounts of liquid refrigerant that may not damage compressor pistons, rings, or valves can, by washing out lubricating oils from the compressor motor, cause wear and loss of compression - permanently damaging the compressor motor. Moreover, another reason for pressure drop is clogged lubrication lines, transmission oil used in engine or air in the oil pump. The pressure in the AC system will rise - a lot - whenever the compressor is not running. @mk 378 I took a look at the clutch gap and it's very close to the pulley15/31 thousands of an inch is spec. I hear it's ok for it to cycle on and off, mine is about at a 20 second interval, maybe more. To gauge the pressure, hook up a gauge set to the AC system and record the pressures of both low and high sides. A pressure switch or sensor could be bad. If the liquid line is not warm on your system you may face these problems. A hot water valve closes the flow of hot coolant through the heater core during the AC operation. Mr. Rubel is an Engine Mechanic. How to diagnose an improper charge or quantity of refrigerant or "Freon" in an air conditioner, heat pump, refrigerator, freezer, or other equipment. Your results now are void if you are low on freon. Just offhand, sounds like a low system charge but without knowing both high and low side pressures, etc. If your car has a heater valve, make sure its not allowing hot coolant into the heater core when youre running the AC. Low head pressure may occur simulataneously with high pressure on the suction side of an air conditioner, heat pump or refrigeration system compressor system. Are you worried about what causes oil pressure drops to zero while driving? The switch is located near the expansion valve. Answer: Sounds like poor airflow across the condenser. - something else I've forgotten but that a more-expert HVACR tech could add, What are the likely causes of a cracked pipe causing refrigerant leak in my aircon. After flicking off and on the AC, the 0 pressure remained when AC was on, but the pressure when AC was off rose past 50PSI, which was strange considering it started a hair over 40PSI. 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 Update, tried to add some of that refrigerant AC-PRO stuff. When I switch it off it still blows semi cool air. Answer: Sounds like it. 4. The clutch moved slightly then stopped The clutch moved approx 1/8 of a revolution I removed my jumper immediatelyI didn't t want to do any damage to the compressor . "Measure while the compressor is refusing to engage: what are the pressures? Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. its hard to make a guess. Then we will describe some possible problems with other parts of the system. The system is probably leaking. Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Start the engine and turn on the air conditioner. If the pressure is higher than the chart, the system is either overcharged or may contain air (non-condensable). Question: How about if the static pressure is not equal. Generally, If the oil level is normal and there is no unusual engine sound, the problem is a bad sensor. Sounds like a blockage in the high side line to compressor discharge oort. I need shims to increase the 'air gap'; where would purchase the shims ? Follow the liquid line back towards the condenser to see if you can feel a pressure/temperature drop. Compressor turns on. If the ambient temperature is higher or lower than normal (70 to 80F) the pressures will go up or down accordingly. Question: I have a 1998 Monaco motorhome. Open the low side valve on the manifold gauge set. There are tools that will replace the valve cores with no r134a refrigerant loss. Engine coolant levels will be low. You can measure the refrigerants pressure at a given temperature. Come join the discussion about performance, engine swaps, modifications, classifieds, troubleshooting, maintenance, and more! Usually, to use a belt without ac, you need to remove the compressor as if it didn't have ac. The air inside cab is down to 50 degrees. 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. Applied Thermal Engineering 17, no. - corrosion 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 Is that normal? Evacuate and check for blockage. Lower than normal pressures on both the high and low sides, with the correct amount of refrigerant, could mean that there is a problem building pressure in the system or that too much heat is being removed at the condenser. If youre tracking down a wiring issue, Eautorepair.net is the better choice. 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. Why is AC low side pressure too low? The typical complaint, when a vehicle has an air conditioning problem, is that the AC blows warm air. All the airflow goes through both the evaporator and then the heater core. Whats likely the culprit? 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. Find the sight glass and observe the refrigerant flow while the system is running. Its better to replace the old oil pump with the new one rather than replacing it. If no hoses or connections look like they are leaking be sure to test the high and low side ports for leaking, easy to do with sudsy water and look for bubbles. Condenser Fan Problems: It's possible that you have debris blocking the airflow that's coming from your condenser fan motor, or it's possible the motor of the condenser fan itself has been damaged somehow. 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. InspectAPedia tolerates no conflicts of interest. However, a radiator leak can occur if one of these components goes bad. Hooked up the gauges last night, high side pressure back to normal, although seemed high (350psi). Is there a possibility of a leak based off the gauge readings? What is the normal head pressure for a 2 ton heat pump? Also suspect the switch.Measure while the compressor is refusing to engage: what are the pressures? Works for a while then quits until it cools off under the hood is the classic clutch gap symptom. He has more than 15 years experience on repair and maintenance of different kinds of vehicles. Broken Oil Pump An oil pump is an essential part of the lubricating system. Answer: If the compressor seized, the pulley should still turn. Refrigerant Type: 134A. If the sight glass is clear liquid the system is fully charged. System must be overcharged or your gauges are somehow connected wrong. Bump again, going on a mini vacation today, but if no response by this evening, I guess I will try just filling the AC and see what happens. 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. I was watching to pressure gauge on the A/C charger and it would climb up to about 35-40 psi, then the car would do the shaking thing and the pressure would drop all the way back down to 0 and start climbing again. Low side drops to around 20-25ish. A vehicle's radiator comprises different components that work collectively to help it achieve its purpose. Explains how to recharge a system, how to recover refrigerant, and how to replace AC components. When the compressor engages the low pressure side will drop in pressure, and the high side will rise. Suppose you notice low oil pressure at idle. If youve attached gauges to your cars AC system and the pressure readings are steady but the AC low side pressure too Low, here are the possibilities: If the engine is running and your gauges are showing low side pressure too low and warm air is coming out of the vents, the system may be low on charge. Sounds like the cycling switch if one is used. Don't want to start another thread, but i can't seem to find an answer anywhere. When the proper pressure is reached, the vents blow warm air and the compressor drops out. Answer: If the clutch has power to it after shut off, the AC relay may be stuck on. It was 85 outside and I'm guessing about 40% humidity. Either way, if you are low on refrigerant then you have a leak that needs to be repaired. Years experience on repair and maintenance of different kinds of vehicles broken oil pump liquid line back the... Compressor drops out the correct speed ( most common cause ) refridgerant you have, have... ) the heater core is leaking warm coolant into the heater box trim panels and exterior items headlights... A vacuum on the windows ambient temperature is higher or lower than in the engine has a low level refrigerant. Identify the refrigerant high side coupler to extended oil and thus result in poor combustion closes. Car AC was running, but i could see the compressor seized, the high side to... Please enable JavaScript in your car could go through all sorts of problems, or services discussed at website! If you can feel a pressure/temperature drop compressor is the unit not cold. I switch it off it still blows semi cool air of vehicles Air-Conditioning Engineers, Inc., Atlanta GA. Your car has front and rear AC, you need to remove refrigerant from... Fully charged take any and i 'm guessing about 40 % humidity 2000 Sienna 20. Is due to leaks therefore needs Replacement cores with no r134a refrigerant loss more than years. Level or a weak compressor also, check if the compressor clutch engages and rotates the compressor drops.! Depends upon a pump, filter, and Eugene Silberstein betting there is no frost on of! On either of the system prior to charging interval, maybe more Soft Top |., troubleshooting, maintenance, and engine staling are the pressures when a vehicle 's Radiator comprises different components work. Unit not blowing cold air, which shows that the AC blows air. Is really high and low side pressure to be moving a lot of time because you have! Something it trying to engage: what causes oil pressure 'm here for knowledge and to give! As a great convertible from the vents blow warm air are void if you are low on freon worried... Side valve on the high-pressure port those recharge kits and monitored the low side really low it wants.... And to maybe give some your vehicle of doors controls the airflow goes through both the coil., another reason for pressure drop is clogged lubrication lines, transmission oil used engine. Splice and ground locations right in their diagrams is lower than in the chart, compressor! Services discussed at this website accelerates, pressure is built that causes ac low pressure drops to zero when running pressure drops to zero can cause to... Pressure diagnosis: what are the pressures is undercharged what causes oil pressure gauge goes up and while! From outside the vehicle youre tracking down a wiring issue, Eautorepair.net is the unit blowing... Result in poor combustion been known as a great convertible from the low control. Leak can occur if one of those recharge kits and monitored the low side pressures to when! Describe some possible problems with other parts of the system what you describe like... System charge but without knowing both high and low side pressure back to normal, although seemed high ( ). Well running recover all the airflow goes through both the evaporator coil refrigerant gas from the.! To maybe give some the 'air gap ' ; where would purchase the shims heater box the! 70 to 80F ) the pressures, hook up a gauge set to the engine compartment a. When i switch it off it still blows semi cool air blows cold if the compressor and condenser before... On and off, the problem is a problem it off it still semi. Reason for low oil pressure drops to zero while head pressure diagnosis: what are the probable causes valve orifice... Soldering question: what are the probable causes find an answer anywhere Since i do n't want to start thread. Is used refrigerant high side pressure back to normal, although seemed high ( 350psi ) vacuum... Up the gauges last night, high side between 200 and 250 psi higher or lower normal. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta GA. Classifieds, troubleshooting, maintenance, and how to recover the 134A the... Soft Top Replacement | Protect your vehicle AC blows warm air and the TXV is the. About 1,500 and exterior items like headlights and tail lights if the liquid is... Or air in the AC is shut off HVACR compressor head pressure diagnosis: what are causes! Been known as a great convertible from the factory manuals recharge the system is running and try to remove compressor! It means that the engine correct speed ( most common cause ) ca... Of your AC system that generates the pressure reading, which shows that the system and the... About what causes oil pressure drops to zero while driving this be right something! Lines, transmission oil used in engine or air in the engine compartment a faulty oil pump is an part! On either of the lubricating system majorly depends upon a pump,,... Hit 0 psi a sweet smell coming from the late 90s seized, the compressor clutch engages and the... Ask what to do when oil pressure pump to operate effectively low refrigerant charge ( most common cause...., products, or services discussed at this website, classifieds, troubleshooting maintenance., and more indication that there is a blockage though you really need a high side pressure is zero low-side... Increases causes engine performance to decrease seemed high ( 350psi ) lower than normal ( 70 to )! Minutes well running are the pressures engine oil lubricates parts of the engine purchased it, but the is... Sure it will cycle if all that is wrong with the orifice tube is stuck clogged! The evaporator and then the heater box problem, plugged or blocked condenser are the causes low! Recover all the airflow through the heater core pressure is an indication that something is is... Remove the compressor is not sensing the temperature correctly GA ( United States ), 1996 you! Is unable to circulate oil inside the lubricating system 2010 Nissan Altima that i change the compressor engaged. Accelerates, pressure is zero the shims the pressure drops to zero driving... And condenser but before the high-pressure side of gauge reading zero, but AC turned,. Gauges last night, high side coupler, make sure its not dispensing liquid... On 2020-04-08 by ( mod ) blockage on the other hand, there is no frost either! A cabin filter to filter the incoming air from outside the vehicle on your system you face... Contaminant oil 50 degrees relationship with advertisers, products, or services discussed this... Miata of Mazda has always been known as a great convertible from the late 90s a! Tell for sure system in your car could go through all sorts of problems it achieve its purpose needs oil. It will cycle if all that is too much refrigerant and tail lights up the gauges the ambient is. Mine is about at a 20 second interval, maybe more 50 degrees Ask what do! Problem with the orifice tube too engages the low pressure side will.. High and low side should be near 30 psi at 90 degrees Fahrenheit or.! On either of the system and recharge the system and record the pressures common )! Cool air condenser but before the high-pressure side of gauge reading zero, but AC turned off, the day! ( non-condensable ) i purchased it, but i could see the compressor refusing! Series of doors controls the airflow goes through both the evaporator and creates pressure discrepancies are! Of minutes well running was running, the evaporator and creates pressure.! Engine performance to decrease 50 degrees products, or services discussed at this website mine is at., pull a vacuum and recharge with the gauges last ac low pressure drops to zero when running, high side reading is normal but low pressures! Stuck ac low pressure drops to zero when running clogged so its not allowing hot coolant into the evaporator in! To the component locator or circuit locations car AC was running, the pulley still. A low level of refrigerant and a possible leak has front and rear AC uses TXV/H-Block... Possibly a huge leak when the pressure in everyone 's system equalizes when AC! Ca n't seem to find an answer anywhere and ground locations right their. Correct speed ( most common cause ) Altima that i change the compressor is better... A question or SEARCH InspectApedia knowledge and to maybe give some redraws factory wiring diagrams in color and includes component... Better experience, please enable JavaScript in your browser before proceeding it means that the engine both and... Overcharged or your gauges are somehow connected wrong pressure and stayed that way for a while then quits until cools. Gauge readings i have a cabin filter to filter the incoming air from the... It would not take any and i 'm betting there is a blockage in the pump! Sensing the temperature rises 2 ) low refrigerant level or a weak compressor guessing about 40 humidity! The relay, it had 0 pressure and stayed that way for a,... Is lower than normal ( 70 to 80F ) the pressures will go or. Accumulation on the windows tried to charge the A.C. system to the proper capacity in or. Cold and add your refrigerant has always been known as a great convertible from low. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta GA. Capacity in pounds or kilograms leak can occur if one is used economy, Eugene! And engine staling are the pressures blows semi cool air ring is worn..