Below is a guide to troubleshoot and check system function. This can be done by most folks.
Look at the front of the ac compressor and have someone turn on the ac from inside the car
. The front of the pulley(clutch) will spin when turned on.
If it does not spin, the low pressure switch (LPS) is not satisfied. Meaning there is not enough freon in the system to operate the system. Means low freon capicity because of a leak.
can be jumpered
to cause the compressor to run (clutch to engaged) which will draw the freon in the system.
is usually a two wire sensor on the suction of the compressor. (between evaporator and compressor) Unplug the sensor and install a jumper, this will engage the clutch. Connect a new can of freon
and fill to system capacity.
The capacity of the ac system will be on a label under the hood, do not overfill. Probably about 2 lbs. Local parts stores (Auto
Zone and Advance
) will have freon with stop leak. This may help the leak. They also make a freon with a UV dye. I always add a single can with dye so that if stop leak does not work I can find the leak in the future.
The system should be filled until suction pressure is about 30 to 38 psi..
Remember the flow for the a/c system is :
1. From the compressor a high pressure (HP
) gas goes to the condenser in front of the radiator.
2. From the condenser a HP
liquid goes to an expansion device (orifice tube or expansion valve)
3. From expansion device the low pressure gas enters the firewall to the evaporator.
4. From evaporator the low pressure liquid/gas mixture goes through the dryer back to the compressor suction.