What Pressures Are Supposed to Be Read in an Automotive Ac System
So you will definitely need a ready of pressure level gauges to diagnose this symptom. Refrigerant is a gas that changes states through pressure which is also how it changes temperature. If at any part of the organisation, the pressure level is not at information technology's desired PSI, the refrigerant may non get cold enough, or cold at all. Click on the image to go a detailed description of the gauges needed to check your system.
Kickoff y'all volition need to check the pressures at idle and record both HIGH and Low side pressure level readings. These pressures will vary depending on ambient temperature (temperature of the outside atmosphere), simply ideally, you will want to run into your low side pressure level between xxx-40 psi and your high side force per unit area between 150-175 psi. If 1 or both are out of that spec, run across the options below to beginning looking further into your problem.
H – besides low
50 – too low
System nether charged or as well much oil
Check visually for any leaks in the organisation. If you are depression on refrigerant, it leaked out somewhere. Await for oil remainder around the hose ferrules, fitting connections at the compressor, condenser, and evaporator or expansion device. If no obvious leak is plant, recover the refrigerant and replace the service ports or valves, evacuate and recharge the system, and add together dye in case there is another leak. You might spend $150-$300 at a shop for this service depending on your marketplace and how much refrigerant your arrangement holds. ***Annotation: It is illegal to vent R134A refrigerant into the atmosphere. Evacuation and recharge should be performed by a licensed professional with the proper machinery.***
Evacuation should be washed with a proper vacuum pump that tin can bring the arrangement down to at least 29.75 "hg (inches of mercury) or more than and concord information technology there for at least 30 mins. Pulling the arrangement down to a vacuum reduces the boiling point and any moisture in the system is and then boiled and turned into a vapor to be removed. This also ensures that all the air has been removed from the system. Both air and moisture, if left in the system, can crusade corrosive impairment to lines and other components likewise every bit wear downward the compressor setting y'all up for premature failure and a lot more money. This means, practise not apply a can of refrigerant from an automobile part store that simply has i gauge on information technology. This is non the proper style to care for your A/C arrangement! You need gauges, a vacuum pump, and a scale to do this correctly. If you do not have these things, accept your auto to a shop.
Once the vacuum is complete, let it sit for about 5 minutes to run into if you lose vacuum pressure level. This will indicate that y'all still have a leak somewhere. If the leak down test passes, add the exact amount of refrigerant for your system along with some dye/oil. Your underhood sticker should inform you of how much refrigerant your system holds and what blazon of oil to use. Y'all merely want to add a modest amount of oil mixed with the dye during the service, close to .5oz will exist sufficient.
When washed, run the vehicle with the gauges still connected and record new pressures. If there is nonetheless an issue, please get back to the DIAGNOSING your AC page Hither. If information technology is blowing cold now… go bask the cool air!
H – besides high
50 – also high
Organization overcharged or air in the system, condenser fins blocked, or fans are inoperative.
Check and make sure the condenser fan is turning on. Some cars have two fans, some have 1 with multiple speeds, while others take a fan clutch. Whichever the example, make sure they pulling as much airflow through the radiator/condenser equally possible. Make sure the condenser is costless of road droppings that may take built up from driving. Anything that is blocking airflow through the condenser tin prevent it from doing its job of cooling down the refrigerant. Make clean condenser, repair fans if a mistake is found, and retest. Evacuate and recharge the system to the proper levels and retest (see to a higher place).
If later on the evacuation and recharge you are finding yourself with the same readings, yous likely take a blockage in the organisation. You can try pouring water over the condenser to see if the pressures driblet and the air gets cold. If the organization drops to normal pressures and the vents are blowing cold air, you will probable need to supervene upon or flush your condenser. I would recommend replacing your drier or accumulator at this fourth dimension besides. The drier has a screen in information technology that filters out the debris and keeps it from entering components like the condenser or compressor. If in that location is, in fact, a blockage from debris, information technology likely came through as a upshot of a damaged drier screen. Supervene upon items, evacuate and recharge, and retest.
If simply the high side pressure level drops, and then it is time to go look at your expansion block. Y'all tin can endeavour tapping on the expansion block, if accessible, to see if anything changes. A lot of times, these devices merely get stuck open or closed from moisture corrosion. If you are looking at pressures around 225psi on the high and 80psi on the low, it would exist a rubber bet to supersede the expansion device, evacuate and recharge arrangement, and retest.
H – OK
Fifty – too low
Evaporator frosting or expansion valve faulty.
Some vehicles accept sensors for specifically detecting if the evaporator is getting besides cold, causing the refrigerant to literally freeze within the evaporator, halting the menses, resulting in a loss of cold air. Well-nigh vehicles do not have a monitoring device for this symptom though so we have to expect at our pressures. If you lot find that the high side pressure is at the desired pressure and the depression side is really low or near to a vacuum, you lot likely take a stuck expansion valve. Supervene upon the expansion valve, evacuate and recharge the organization, and retest.
H – as well low
L – also high
Low refrigerant level or failing compressor
With the gauges connected, rev the engine to 2000 RPM and watch what the pressures in the Air conditioning organization do. Do they move closer together (loftier side gets lower while low side gets higher) or practice they move away from each other? If they move abroad from each other, start with evacuating and recharging the system and retesting.
If they move together, yous have a weak compressor and it is recommended to supervene upon the system. A proper AC system replacement volition include AT To the lowest degree a compressor, receiver/drier (or accumulator), expansion valve (or orifice tube), and flushing out the evaporator, condenser, and lines before reassembly. Some vehicles, like a lot of Fords and Chevys, will demand the condenser and/or manifold lines replaced considering they are hard to flush debris from because of the fashion they are designed. If Whatsoever debris is left in the arrangement after a compressor replacement, you lot can set yourself upwards for another compressor failure if that debris circulates its way back to the compressor in the system. Some systems, the drier is role of the condenser, similar a lot of Hondas. Afterwards the parts are replaced, yous will need to evacuate and recharge the organisation. See above for proper process. You just spent a lot of money on the new system and time or coin installing it. Make sure this job is done right. "If you call back taking it to a professional is expensive, wait until you hire an amateur."
These are just some of the things that could be wrong. Recall that every vehicle is different and there are different controlling and monitoring devices that can contribute to your ac not working. If you would like specific advice on your vehicle, please check out our Enquire A Mechanic section Hither and one of our ASE certified technicians tin can assistance yous further!
Source: https://carhowto.com/what-do-my-car-ac-pressures-mean/
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