Skip the auto shop - Our mechanics make house calls

Q: I am adding refrigerant. I need to know the low side pressure if the ambient temp is 95 deg.

asked by on

I am adding refrigerant to my 2004 f150 5.4L. I need to know what the low side PSI should be if the ambient temp is 95 deg.
My car has an automatic transmission.

A: When the A/C compressor is running, the low...

When the A/C compressor is running, the low side pressure should be between 20-40 PSI. There is no spec for A/C pressure when the system is off though, rather they just specify a specific amount of refrigerant that should be in the system. This is done by using a refrigerant recycling machine, and recovering all the old refrigerant, putting the system under vacuum, and then putting in a specific amount. The same results can also be achieved by using a precise refrigerant scale and A/C gauges. I would not recommend using a simple can of refrigerant, as there is no way to accurately monitor the amount of refrigerant in the system. If you want to have this done for you, a technician from YourMechanic can come to your home or office to properly perform an AC recharge on your vehicle.

Was this answer helpful?
Recommended services
Get a Quote

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Car shaking while accelerating

You could have several issues going on there. I would start by having a mechanic, such as one from YourMechanic, check out the recent work. It is possible for the CV axle nut to have come loose. The noises while...

Q: Do I replace the lower radiator hose when installing a new radiator?

The lower radiator hose should be able to be removed by releasing the tab on the bottom of fitting and rotating the hose connection 45 degrees then pulling the hose off of the radiator connection. Once the hose is removed...

Q: Coolant leak

The two most common coolant leaks on this vehicle that other owners have encountered are the radiator and water pump. I recommend you have a mechanic, like ones from YourMechanic, to inspect your car for the coolant leak issue.

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...