Help, My Car Is Way Too Hot!

There is nothing worse than having no AC, especially when living somewhere temperate or tropical. In Florida for instance, having no AC is a borderline death wish. Below are a few reasons why your AC might not be working or blowing hot air.

AC Background

AC is a process in which your vehicle takes outside air (or circulated air already in the cabin) and cools/dehumidifies it. This process occurs in a variety of different tubes, fittings, and parts. Systems work with evaporation and condensation to make sure air doesn’t feel “thick” and “humid.” A typical unit has about six pieces including a compressor, condenser, receiver-drier, thermostatic expansion valve, evaporator, and refrigerant.


The most common AC killer is a gas known as Freon. This substance is found in the majority of cooling systems; Freon is found in AC units, fridges, freezers, and anything else that has a self-cooling unit. This material is a gas / liquid combination that moves throughout the air conditioning system. It is compressed and pushed around under pressure and works through different sized metals and hoses. The Freon pushes through a valve called an expansion valve that changes the gases state to expand and contract it.

Idling Issues

If your system struggles to cool or can’t at all, you may have an air flow issue. The condenser requires air flow over the top of it to keep it from overheating. Check your vehicles cooling fan motor or fan blade depending on the make and model. If idling issues coincide with overheating, your AC cannot run efficiently and you may have an issue with your radiator or other cooling devices.

Freeway Driving

If the AC seems like it’s on fritz but will work occasionally, this is probably due to freeway driving. As the car speeds up and experiences more wind from higher speeds, the vehicle runs more efficiently. The condenser is quickly cooled while warm air is carried away. Check Freon levels because once brought back to slower speeds, the flow of Freon across the system decreases and the efficiency can ebb.

Zero Cool Air

Basically, there is no easy answer for this; it can be a combination of anything. You may have a large Freon leak; there could be broken belts, or possible defective valves. If a leak occurs, AC quality will drastically decrease until it disappears. A leak can occur in any part of the system and is a pain to try to diagnose. Mechanics must also look for a defective expansion valve, a damaged compressor, or for clogged pieces. Many diagnoses require a lot of labor or the use of dye’s to try and find leaks.

Winter Driving

Even though it seems counterintuitive to run AC units in the winter, it’s actually a very important part to the longevity of your system. The typical rule most follow is ten minutes of run time per month; this allows all the pieces to remain lubricated and working efficiently. There is actually a light mineral oil contained in the refrigerant that can lose its quality if never run.

Mitigating / Repairing AC issues

The easiest way for the average person to fix their cars AC is to get a Freon recharge. These kits costs less than $50 and can be bought at any automotive store and other box stores like Wal-Mart and Target. The kit is self-explanatory and requires the hook up of a Freon gun to your AC unit. Total time takes no more than half an hour. When checking your system also refer to your owner’s manual; the manual has all necessary information and requirements that your car needs. To check your system a little research can be conducted. Check online to determine what your AC system looks like and try to follow the connections and hoses. Try to determine leaks and possible malfunctions by following the lines and testing the AC.
Having no AC is never fun, but diagnosing and fixing can be very expensive. When talking to your mechanic, ask about possibilities and what he thinks the problem may be. Be warned of unneeded repairs and make sure to get the entire rundown of what occurred in your AC system. Before bringing your vehicle in, try utilizing a Freon kit; if it only works for a couple weeks, seek professional help.
Josh McCarthy is from Orlando, Florida. He is a finance major at the University of Central Florida and enjoys trading stock options. He enjoys all athletics and is trying to make money for an engagement ring. Josh is also a professioanl blogger for Linear Automotive, a certified import body shop & repair service shop.
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