No Cold Air Blowing From AC in 1999 Saturn SL2, I Checked the pressure with a guage it was really low, i added 2 cans of R134 to the low side port. compressor kicks in. runs well but after running the car for 30 mins still no cold air.... Checked for leaks after adding the 2 cans, was unsuccessfull in finding any. What would be causing no cold air...?

Pressure has built up in the system possibly from a clogged orifice tube/expansion valve. Replace the orifice tube/expansion valve, thenPull a vacuum on the system and recharge.

ac not blowing cold can be caused by numerous causes. First it has to be determined if the system has enough freon. Your system has a pressure switch that will shut your system down when it has a low charge. A technician can perform a diagnostic proceedure to determin the cause. If you choose to attempt yourself you can purchase a can of R134 refrigerant that has a guage on it that will tell you if you have a sufficient charge in the system. This is connected to the LOW side ac line. LINE. If you do, then nxt step would be is to check all fuse related to your ac. If all checks ok the seek a professional.

Hi, determine if your car uses R134 or R12 refrigerant. You will notice screw type connectors on the both the High Pressure Side and Low Pressure Side lines in models using R12 refrigerant. R134 compatible models have quick connect valves on both sides. Models made before 1995 may use the old R12 refrigerant. If this is the case, you must have your Chrysler's air conditioning system retrofitted to use R134 refrigerant. Mixing R12 and R134 refrigerants is dangerous and may cause damage to your vehicle. Check your air conditioning system pressure using an automotive air conditioning pressure gauge. Keep in mind that in order to get an accurate reading, the air conditioner has be turned on the coldest setting with maximum blowing power. Remove the Low Pressure Side port valve cap and set it aside. The location of the port varies, but it is usually in front of the engine block. Attach the refill hose to the port on the Low Pressure Side of the air conditioning system. The Low Pressure Side port is smaller the High Pressure Side port. Because the ports are different sizes, the refill kit hose should fit only on the Low Pressure Side port. Additionally, the High Pressure Side port will usually have a red cap or be marked with an H or the word High Allow the air conditioner to **** the refrigerant out of the can by slowly turning the valve on the refill kit hose. Pay attention to the way you hold the can. Most kits will have you hold the can upright when you recharge the air conditioning system. It may take as long as 10 minutes to empty a single can. Turn the valve to the off position and remove the refill hose from the port. Recap the port before closing the hood. Let the air conditioner stay on for at least 30 minutes. This allows the refrigerant to move throughout the entire system.
Take care

somewhere around 1.6 pounds (1lb.14ounces) of R134a if system is evacuated and 3 ounces of oil with new compressor.
keep pressure on the low side around 34-37psi & it should blow snow. Below are normal car AC pressure readings with 134A.

• Normal readings on high and low side with AC OFF (static pressure) – Depends on outside temperature, but normally is between 80-105 PSI
• Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s – Ranges from 25-35 PSI –
• Normal high side reading ranges from 200-350 PSI

Don’t assume that if adding little Freon is good that adding a lot is better! Overcharging just a little can decrease the performance of the system and possibly damage the compressor.
DIY recharge kit:
With the AC on the coldest setting, use a thermometer in a middle vent. Normal vent temperature readings will vary depending on the (ambient) outside temp. The vent temperature should range from around 42-55 degrees in my experience. If normal gauge readings are obtained and the vent air is cold – STOP don’t overcharge the system.
Thank you for using fixya and be safe.

There is no low a/c gauge on cars (most cars, anyway). It sounds like your a/c is blowing warm and someone suggested that you check the low pressure for freon.
The a/c has a low pressure side and high pressure side. The pressures can be checked by attaching a set of gages to the two ports of your a/c system. The low side needs to be at about 34psi to get cold air. A cheap set of gages can be found for about $40. Or you can buy a freon kit with low pressure gage at the auto parts store, such as Auotzone, Pep Boys, O'Reilley's, etc.
It sounds like you're not really familiar with a/c systems, and messing with them can be dangerous. You really need to work with someone who knows, or take it to a shop.

replaced clutch, driver ac belts on 2000 montero sport a/c is still not blowing cold any ideas

I don't have a solution, but the same problem. I can't figure out howcome it is cooler (though not cold) when the fan is on 1. Hot all other settings

Sounds like the A/C system just needs to be recharged. When was the last time you had this done? Just take it in to your mechanic and he can do it for you and if that's not it for some reason, then he will be able to find the problem but most likely you need more freon added.

Benjamin

Freon is low, go to walmart and buy a R134 kit with guage attached (not very expensive. Connect it to the low pressure side of the A/c system (don't worry the connection won't fit on the high pressure side) Read the guage on the kit and add as neccessary. It truly is that simple.

If your compressor is working the low side should be 15-38 psi. If you have 100 psi that means the compressor is not doing what it should. Make sure the outer clutch is engaged with the pully. If not A/C system check should be done.