It is the Honda A/C Compressor that pressurizes the Freon in your air conditioning system so it can be driven through an orifice and expands, causing the cooling effect felt by the passengers in your vehicle. The A/C compressor is mounted on the top front of the Honda engine and is provided with power from the drive belt system located there.
The A/C compressor is the components on the system that is connected to both the low and high pressure sides of it. The Honda owner can observe these sections of the system by just looking at the size of the A/C hoses and pipes used on each side of the system. The high pressure side has smaller diameter conduits while the low pressure side is almost twice the size in diameter.
The high pressure side of the A/C compressor is connected to the condenser by the way of the smaller tubing. On this conduit is a nipple. This is the place where the gauges are attached to read the high pressure of the system. The low pressure side of Honda A/C compressor is attached to the evaporator and it also has a nipple in the conduit. This is not only the place for the reading on the low pressure side of the system but also the place refrigerant oil and Freon is added. If the Freon or refrigerant oil is attempted to be added on the high side of the A/C system, the container can and more than likely explode from the extreme pressure being exerted on it.
If the A/C compressor is making a knocking noise, then refrigerant oil should be added to the system on your Honda. This component is a dry sump device that does require periodical oil injections to stay in proper functioning status.