Your air conditioning should be checked for proper operation and Freon charge at least once a year. Freon is very hard to contain in an automotive system. The reason is your air conditioning compressor operates at all different speeds due to engine RPM. The rest of the system is comprised of many dissimilar materials that expand and contract at different rates and along with the movement of the engine; this allows a minute amount of Freon to escape. This is normal and that’s why the system should be checked for low charge. You’re probably asking yourself does that mean I have a leak; probably not, at least not significantly. Checking the amount of Freon in the system is very important because the Freon in the A/C system carries the refrigerant oil through the system to lubricate moving parts and seals. Insufficient Freon can damage the compressor, expansion valve and seals resulting in very costly repairs. You might also say I don’t use my air conditioning in the winter, but you do! Every time the defroster is turned on your air conditioning compressor engages to dry air before directing it to the windshield. Waiting till your air conditioning is needed during warm weather to determine that the system is low on Freon may be to late to avoid unnecessary damage.