Better Beaters - Building Cars and Daily Drivers

 Thinking about automotive air conditioning. Part One.

The old fashioned "hang on" swamp cooler. This one looks pretty spiffy!
photo from web.

To be more specific, thinking about the a/c in my vehicles.

The hottest days of Summer are here, and it is now that you'll focus on how effective your cars a/c system is working. What seemed adequate in 80 degree weather isn't cutting it at temperatures of over 100 degrees!

Automotive a/c has been one of the most appreciated developments that has come from American manufacturers. American a/c was renowned for years, as it was so effective in bringing down high temperatures quickly and effectively. 

Cute, but not very effective.
photo from web.

A lot of people lived in homes that were not air conditioned, but at least they could find blessed relief during their commute home. Cooler drivers are not only more comfortable, they are also much calmer and practice much better judgement.

All of my current fleet have a/c, a few of my cars are pretty old, and my '96 Mustang needed some work shortly after I bought it. It developed a leak in an a/c hose, and they were replaced and the system recharged  over ten years ago. It still blows cold, but it's not as cold as it once was. 

I would guess that some of my cars need to have the a/c recharged. This was a common service years ago in many corner gas station garages. Now there are fewer places to have this done. My regular mechanic retired, and his replacement recently went into another line of business. 

So I've been looking for a local place that could handle this for me. 

I happened to be driving my truck and I was thinking that it wasn't as cold as it used to be, though I didn't find it's performance to be particularly lacking. 

I had found a shop along White Rd. on the East side. I had some tire work done at this shop years ago. There was a big sign indicating that they did a/c work, so I stopped to ask about it. The technician, a serious looking, older Indian gentleman, named Sunny, advised me that they could do it, but that he should first hook up the gauges and take a pressure reading as a diagnostic test. I asked him how much this would cost, and he said that it was free.

gauges and a vacuum pump.
photo from web.

He hooked up the gauges and told me that the system was a bit low

He advised that it needed a flush and recharge, at a cost of 157.00.

I asked when he could do it, and how long would it take. 

Sunny said he could do it right then and it would take around twenty minutes. 

I have several cars that might need a/c service, and I needed to find a  shop that would do this at a reasonable price. I decided that I needed to trust someone. I've been dealing with my Ford dealer for some extended warranty work, and really don't trust them, or like dealing with them. 

So I let Sunny do his thing. Her told me to sit in the passenger seat while he performed the service. The engine was running and the a/c was on during the process. Once completed he told me that I should clean the condenser when I got home, and I would feel a bigger improvement. I saw him use compressed air to blow through the condenser fins before he charged the system. He told me to just use compressed air and a garden hose, nothing more powerful than that. 

On the drive home I didn't feel that the a/c was any cooler than before. I parked the truck in the driveway and used my compressor to blow debris from the radiator condenser area. 

This isn't my radiator, but you really should check and clean
 this area once in a while!
photo from web.

I hadn't cleaned under the hood of my truck since I bought it, but it wasn't too encrusted with dirt and bugs. Then I sprayed some Castrol Super Cleaner on the core, let it sit, then flushed it with the garden hose spray nozzle. I should have used the compressed air to blow the excess water out of the area, instead I just decided to let it dry with the engine running.

Bad Idea.

I fired up the engine with the hood open and water started spraying up, out of the area. So I closed the hood and decided to drive the truck around. It was okay for the first few minutes, then it started to misfire. After a minute or two, the engine would only run at part throttle and the CEL lit up! All that water had wet something electrical, and resulted in the misfire. I decided that I would keep the speed down and hope that things dried out on their own. A few miles from home I pulled into a parking lot, opened the hood and let the engine continue to run. It seemed to be a lot drier! 

After another ten minutes I closed the hood and headed home. Luckily the CEL had gone out and the engine seemed to be running normally, so I continued my driving and entered the freeway. I added another ten miles or so and returned home.

During this drama, I'd forgotten about the a/c, but switched it on during the final miles home. It was working, but didn't seem any cooler than when I started. I knew that the shop had done the service, I watched them perform it. I didn't think that they had cheated me. But I didn't have any objective measurement that could demonstrate an improvement. I hadn't tested the system beforehand.

I went online and asked, "how cold should my a/c system cool the air.?"

Most of the initial responses indicated that it should cool the air a minimum of twenty degrees cooler than outside temperatures. That made sense, as even home a/c systems can only be effective up to certain temperatures, once it gets hotter than 100 degrees, maintaining a low temp like 68 degrees isn't possible. Our old home system couldn't maintain the temp at 78 degrees under those conditions, and would run constantly. Recently we had a new HVAC system installed which performs much better, and is capable of maintaining that temp more consistently. Hopefully this will reduce our energy bills, but when the heat exceeded 100 degrees like it did recently, it had it's work cut out for it in our old, not well insulated house. 

Some of the responses indicated that the car a/c should ideally cool the air as low as 35 to 45 degrees in moderate temperatures. Then I found a couple of videos explaining how to measure the effectiveness of the a/c system. It involved using a probe type meat thermometer placed in the center air vent, after closing the other dash vents. 

There are other factors that can affect the system, like a blocked or dirty cowl vent, or cabin air filter, as well as a dirty or blocked condenser. It makes sense to change the filter if your car is equipped with one, and to clean the condenser prior to testing the temp. You might find that the system is working well enough without a need for service. 

I did perform a test of my truck's a/c system, I''ll describe my findings in a future post. I will also detail how I cleaned and tested the a/c on my other vehicles.