Air Conditioning Preservation


#1

On my previous cars (1992 Mercury Tracer and 1995 Taurus) the air conditioning eventually went out. That has me thinking about how to keep it going for as long as possible in my new car (2011 Honda Fit). My theory is that by not putting the temperature on the lowest setting, and not running the fan speed past the 2nd setting, that the system will go longer before needing to be replaced. Am I right?


#2

Nope. Really not much you can do to make it last longer.


#3

No, you are not correct.
First, the fan speed has nothing whatever to do with the A/C system itself. The fan merely moves air, whether it is heated air, cooled air, or ambient temperature air.

As to the temperature setting of the A/C system, these systems can vary quite a bit from car to car, and I don’t know exactly how the A/C system on a Fit is designed.

There are 3 types of system designs, as far as I know.
The oldest ones would cycle the compressor on and off in order to maintain the temperature that the driver selected. On that type, if the driver selects an A/C temp that is high, the clutch on the compressor will actually wind up with more wear and tear than if the compressor ran constantly.

Newer-design systems have the compressor running at a constant rate, and heated air is blended into the cooled air in order to maintain the desired temperature. On this type of system, selecting a higher temperature will have no effect on the way that the compressor or its clutch runs.

The newest type of A/C system uses a variable displacement compressor, and this uses what some have described as a “wobble plate” in order to maintain the desired temperature. Since I am not as familiar with this newest type, I am not sure about how the temperature that is selected might bear on the wear and tear on the compressor.

The biggest A/C problem in my experience is the drying out of seals in the system, thus allowing pressurized refrigerant to escape, and necessitating repair and recharging of the system. Largely, this can be avoided by running the A/C for at least a few minutes every few weeks–even in the winter. Since most HVAC systems run the A/C compressor when the Defrost setting is selected, you wind up running the compressor by default.

In my 46 years of driving, I have never owned a car that had an A/C failure–even on cars that were as old as 10 years. On the other hand, I know of people who have had multiple A/C failures on various cars.

I think that most A/C systems are actually very reliable, and that as long as the system is run perodically during all seasons of the year, and as long as there is no collision damage to the car, failure is not likely. However, there is always the element of chance that one will wind up with a car whose system has a shortened service life.

My advice is to set the temperature to the setting where you are comfortable, and not consider making yourself uncomfortable in order to–theoretically–make the system work longer before breakdown.


#4

Other than agreeing with everyone else’s comments, I will only add this.
If there reaches a point where you think the A/C system is dropping off in performance and it needs a partialy recharge due to loss of refrigerant I would suggest that any partial recharge include adding an ounce or two of refrigerant oil.

Any time refrigerant is lost oil will be lost. When systems are recharged some add refrigerant but that does not replace the oil that is lost. Over the long haul if the oil loss is severe enough compressor damage, even catastrophic, can occur.

This is especially true of modern cars as most of their compressors are mounted down low. Even when not in use the system is pressurized and oil pools down low. In turn, this means that oil loss can occur from a leaky compressor shaft seal, etc. even on a non-operating system.
In the old days many compressors were mounted up high and while they may leak refrigerant over time would not have a tendency to leak as much oil out.


#5

When the AC on my cars doesn’t work, which has happened on occasion, I get it fixed, regardless of cost.

I consider the AC to be part of the safety systems on the car, since it is important in defogging the windows.

Use it, stay comfortable, and don’t worry about it. Nothing you do the temperature or fan settings will make any difference in how long it lasts. If it stops working, get it fixed.


#6

Run it throughout the off season(s) at least a few times a week. Your owner’s manual probably says to, in so many words. Use it on cold, rainy/snowy nasty nights to 1. Keep the windows clear, 2. Verify the operation of the system in the off-season, 3. Circulate refrigerant/lubricant in the system, which is good for it in the off-season.

It may fail to engage when the ambient temp is below say, 30F, which is normal.

jmw


#7

Most refrigeration systems use a hermetically sealed compressor. These systems last forever without problems…Automotive systems use “open” compressors with a troublesome ceramic shaft seal…In many cases, here is where the trouble starts…Another trouble spot are the rubber hoses and their connections and seals…if you get 7-10 years out of an automotive system, count your blessings…


#8

On most cars you don’t have to turn on the a/c in the winter, they automatically use the a/c system when you select defrost.


#9

Unless your A/C system was designed by the Keebler Elves (no offense to elves meant), it should last indefinitely. The main cause of problems with auto A/C is leaks, and you can’t do a lot about that except fix them when they occur.

Probably the best thing you can do to keep it running right is to use it frequently–this will keep the seals and other parts lubricated. It’s also beneficial to make sure that you don’t run it if it’s not cooling right—if it’s low on charge, it can suffer from lack of lubrication, as the oil is carried by the refrigerant. Systems low on charge also cycle on/off more frequently, which can cause wear to the compressor clutch.


#10

Running the fan on lower setting may cause the compressor/clutch to cycle and off for frequently thus possibly shorting the life of the clutch/compressor


#11

The best thing you can do to protect the Fit’s AC is to install a lower grill guard to protect the condenser from road debris.