In Case You've Wondered

My blog is where my wandering thoughts are interspersed with stuff I made up. So, if while reading you find yourself confused about the context, don't feel alone. I get confused, too.

If you're here for the stories, I started another blog:

One other thing: sometimes I write words you refuse to use in front of children, or polite company, unless you have a flat tire, or hit your thumb with a hammer.

I don't use them to offend; I use them to embellish.

Monday, May 7, 2012

A Little Auto AC Advice

I've been around air conditioning my entire life. In the past, I avoided knowing too much, since I had a father, and brother that were experts. They'd help, so I avoided the troubleshooting. Things are different know. They're both gone, so I've sharpened my skills and do what I can.

My pickup AC started giving me trouble. It was short cycling, and before it could get cold, the compressor would shut off, only to repeat the process. I knew the process of short cycling usually indicated a low Freon charge, but I called a business acquaintance that's an expert for some information.

Long story short. His advice: "If the low pressure side is 45 psi, or so, stop hunting the problem and change the clutch cycling switch."

That wasn't the situation. It was cycling to the low pressure cutoff point and shutting down. I figured I'd find this before I started the engine due to the low pressure reading on the gauges in relation to the ambient temperature. According to the pressure of 79 pounds, it should have been much cooler than the 85 degrees Fahrenheit ambient temperature, so I wasn't real surprised when the cycle switch didn't appear to be the problem.

I started adding a can of R-134A, with dye, so I could check for leaks. Within an ounce or two, the compressor quit cycling and the low side pressure started rising. I quit at a half can with a decision to add some more the following day. The AC was blowing cold air, even though the suction pressure was still a little on the low side.

The following day, a quick glance of the pressure in reference to the ambient temperature showed my system was still low on Freon, so I added the rest of the can. After it was gone, the suction side pressure was 34 psi, which is an acceptable range. I would leave it alone for a day or two, then check it for leaks.

Early this morning, before the sun rose, I started looking on the engine for leaks. I used an ultraviolet pen light, with special glasses, to examine the different parts of the system. The condenser coils (by the radiator) showed no signs of a leak. The same for the hoses and fittings. The water dripping from the evaporator coil (in the dash) was clear and had no dye. The low side connection on the accumulator showed signs of dye, which was expected, since that's where the quick-break connections spew a little Freon when you disconnect the lines. Further examination revealed what I think is my problem: the clutch cyclic switch. It's covered with dye, but not where I would have expected the leak to be. It looks like it's internal to the switch, and not the connection. Most of the dye is around the electrical connector. I'll change the switch, and then examine everything one more time before I finish, which will require checking the high side and low side pressure and adding Freon if needed, which I think it will require.

So, after such a long post, what's my advice? Don't mess with automobile air conditioning unless you have some  knowledge, or somebody to stand over your shoulder to guide you. Normally, I wouldn't even think of writing this, but after reading how some people just add Freon, without checking pressures and then adding it to no avail without checking the high pressure discharge of the compressor made me think of the possible problems that can develop. Sometimes it has nothing to do with the charge, and adding Freon can only compound the problems besides being a waste of money. Any major repair usually requires refrigerant recovery, parts replacement and a vacuum pulled on the system to verify there aren't any leaks and guarantee there isn't any moisture in the system. So, adding Freon to a system with a blockage, or bad compressor will only be wasted money.

Still, if you know what you're doing, it's good to do such repairs; at least it is for me. I like knowing how things work and I pinch pennies where I can. Even if you know enough to change parts - even major parts, such as the coils, or compressor - the final pulling of a vacuum, refrigerant charge and fine tuning of the system is usually best left to the experts. They have the equipment, specifications and experience.

I may be through with my repair, or not. The shrader valves could start leaking, which isn't uncommon. Besides wearing out, they have a tendency to start leaking when disturbed. I'll keep my fingers crossed they don't..


  1. Yep. My A/C work was back in the R12 days when we didn't have to recycle. Just as a rule of thumb, every time I cracked the system open somewhere meant an automatic replacement of the dryer and expansion valve, plus flushing and vacuuming before adding freon.

    Just adding freon with no clue is for sure a bad idea - if there is some blockage or if the high pressure switch goes bad, the pressures can ruin the compressor, blow a line, and/or degrade seals. All of which you are well aware of fer sure.

    Never did have a shrader valve go bad, but I did change 'em out just as a preventative once on one truck.

  2. From talking with a friend in the business, the shrader on the high pressure port is notorious for leaking with my year model truck. That's why I'm hesitant to hook up the high side gauge.

  3. Well, the Taurus goes in tomorrow. Now I KNOW I'll never figure it out.
    I can charge a residential or industrial, but the car gives me fits.

  4. Oh which is really so awesome of you to discuss such a awesome weblog with us. I appreciate your time and effort , hardwork and analysis behind giving such an useful articles positioning weblogs. I must say I have never surfed such a awesome weblog until now! Thanks again
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  5. thansk for the insight post.this is not little bit of information for i think about me that i am an expert of AC by reading your advicing post.
    Kenmore Appliances Repair

  6. i will employ your advice for my auto ac today. its insightful for DIY.thanks

  7. This is a good reminder to all car owners - don't mess with your car’s air conditioning unless you absolutely know what you’re doing. You have to be thoroughly familiar with all its components, understand the air conditioning process, be able to identify the cause and effect of tinkering with any of the parts before you try laying your hands on anything.

  8. That’s really how it should be, repair only what you know how to repair. If you don’t know how to fix a part, like the air conditioner, just take it to the car repair shop and let the mechanics do the fixing for you. Always choose which option will provide best result.

  9. Being familiar with car repairs is a huge advantage. But sometimes, there are repairs that are very difficult to handle, like the air-conditioning system. So it’s better and more practical to let a trained technician do it. This will not only save you time and money, but also give you an assurance that your car will be fixed properly. Anyway, thanks for the advice. And I hope your car is working just fine now.

    Felicia Simmons @ Brandon Auto Repair